Iodine

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Iodine and chemically related compounds have been tested for genotoxicity in a variety of test systems both in vitro and in vivo (See Additional information box, Table 1 below). Based on release of iodine ( I₂) and similar mode of action, mutagenicity data from iodine, iodine tincture and PVP-I are considered interchangeable.

Therefore, based on the overall weight of evidence for in vitro genotoxicity, the conclusion for gene mutation in bacteria is equivocal, the conclusion for in vitro cytogenicity studies in mammalian cells is positive and the conclusion for in vitro gene mutation in mammalian cells is negative.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published literature study, guideline-comparable with limitations: - No replicates reported - Lower number of metaphases scored than recommended by current OECD guideline. - No positive control.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

other: Syrian hamster embryo cells

Metabolic activation:

without

Test concentrations with justification for top dose:

0, 400, 600 and 800 µM

Vehicle / solvent:

- Solvent used: DMSO 60 mg/mL

Untreated negative controls:

yes

Negative solvent / vehicle controls:

other: not required

True negative controls:

no

Positive controls:

no

Remarks:

Not reported

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium


DURATION
- Preincubation period: Overnight
- Exposure duration: 24 hours
- Expression time (cells in growth medium): Not reported
- Fixation time (start of exposure up to fixation or harvest of cells): Not reported


SPINDLE INHIBITOR (cytogenetic assays): Colcemid (GIBCO, Grand Island, NY, USA) 0.2 µg/mL
STAIN (for cytogenetic assays): Not reported


NUMBER OF REPLICATIONS: Not reported


NUMBER OF METAPHASES: 100 per experimental group


DETERMINATION OF CYTOTOXICITY
- Method: colony-forming efficiencies


Metaphase chromosomes were prepared as described by Tsutsui et al. (Mutat. Res. 373: 113-123, 1997)

Evaluation criteria:

Statistical significancy between treated cell and control

Statistics:

P value, χ2 test

Species / strain:

other: Syrian hamster embryo cells

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

not examined

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Table 1: The ability of iodine to induce chromosome aberrations in SHE cells.

Conc. (µM)	Relative colony forming efficiency (%)	Type of aberrations (%)									Aberrant metaphases (%)
		CG	ICG	CB	ICB	E	O	D	D	F
0	100	0	0	0	0	0	0	0	0	0	0
400	75	2	3	1	1	0	0	0	0	0	5.0
600	62	9	5	1	0	0	0	0	0	0	13.0*
800	61	10	8	1	2	2	0	0	0	0	19.0*

CG, Chromatid gaps; ICG, isochromatid gaps; CB, chromatid breaks; ICB, isochromatid breaks; E, exchanges; O, ring chromosome; D, dicentric chromosomes; F, fragmentations. * Significantly different from control (P<0.01, χ²test).

Conclusions:

The ability of iodine to induce chromosome aberrations was examined using Syrian hamster embryo (SHE) cells in a testing design similar to OECD testing guideline 473 . Under testing conditions, iodine induced chromosome aberrations in Syrian hamster embryo cells

Executive summary:

The ability of iodine to induce chromosome aberrations was examined using Syrian hamster embryo (SHE) cells in a testing design similar to OECD testing guideline 473 . SHE cells in tertiary culture were plated, incubated overnight, and treated with iodine at varying concentrations for 24 H. Cells were harvested with 0.1% trypsin. Three hours before harvest, Colcemid was administered and metaphase chromosomes were prepared. 100 metaphases were scored per experimental group. Statiscally significant increase in the frequency of chromosome aberrations were induced in SHE cells treated at the two highest dose levels.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - No metabolic activated trial. - Lower number of metaphases were scored compared to current OECD guideline. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Justification for type of information:

Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable.
Further information is included as attachment to attached background material.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

other: Human dental pulp cells (D824 cells)

Metabolic activation:

without

Test concentrations with justification for top dose:

3-h assay: 0.03%, 0.1%, 0.3%
30-h assay: 0.01%, 0.03%, 0.1%

Vehicle / solvent:

No vehicle

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

3h treatment

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: In a first assay, cells were treated for 3h with the agent or 4-nitroquinoline 1-oxide (4NQO) as positive control. In a second assay cells were treated with iodine tincture for 30h.
- Expression time (cells in growth medium): In the first assay, cells were incubated for a further 27 h. In the second assay, cells were continously treated with iodine treated for 30 h, as indicated previously.


SPINDLE INHIBITOR (cytogenetic assays): Colcemid 0.02 µg/mL (GIBCO/Invitrogen, Tokyo, Japan), administered three hours before the end of the incubation period in both assays.
STAIN (for cytogenetic assays): Not reported


NUMBER OF REPLICATIONS: No data on replicates.


NUMBER OF METAPHASES EVALUATED: 100 metaphases per dose group (see result table for info on negative and positive controls).


DETERMINATION OF CYTOTOXICITY
- Method: relative cell number (number of cells treated relative to the number of cells in the control cultures x100). Briefly, D824 cells were plated in triplicate and incubated overnight. The cells were treated with iodine tincture at varying concentrations for 3 h. After washing with fresh medium, cells were incubated for further 27 h. The number of cells was counted after harvesting with 0.25% trypsin. For the 30h experiment, cells were treated for the same period of time.


OTHER EXAMINATIONS:
- Determination of polyploidy and endoreplication: Yes, but counted as chromosome aberrations.

Metaphase chromosomes were prepared as described by Tsutsui et al. (Mutat. Res. 373: 113-123, 1997)

Evaluation criteria:

Statistical significance on the incidence of chromosomal aberrations between treated cultures and control.

Statistics:

P value, χ2 test

Species / strain:

mammalian cell line, other: D824 cells

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

3 h exposure

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

valid

Species / strain:

mammalian cell line, other: D824 cells

Metabolic activation:

without

Genotoxicity:

positive

Remarks:

At highest dose only, 30h exposure

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not specified

Untreated negative controls validity:

valid

Positive controls validity:

not examined

Additional information on results:

See tables below

Table 1: Ability of iodine tincture to induce chromosome aberrations in D824 cells treated for 3 h.

Conc. (%)	Relative cell number (%)	Number of metaphases scored (%)	Type of aberrations (%)						Aberrant metaphases (%)	Polyploidy and endoreduplication
			G	B	E	D	O	F
0	100	500	1	0	0	0	0	0	1.0	3.6
0.03	70	100	0	0	0	0	0	0	0	4.0
0.1	68	100	1	0	0	0	0	0	1.0	7.0
0.3	60	100	0	0	0	0	0	0	0	3.0
4NQO(µM)
0.5	59	100	7	11	1	0	0	0	19.0*	5.0
1.0	52	100	9	21	1	0	0	0	25.0*	19.0*

G, gaps; B, breaks; E, exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations; 4NQO, 4-nitroquinoline 1-oxide.

*Significantly different from control (P<0.01, χ²test)

Table 2: Ability of iodine tincture to induce chromosome aberrations in D824 cells treated for 30 h.

Conc. (%)	Relative cell number (%)	Number of metaphases scored (%)	Type of aberrations (%)						Aberrant metaphases (%)	Polyploidy and endoreduplication
			G	B	E	D	O	F
0	100	300	1	0	0	0	0	0	1.0	3.0
0.01	110	100	1	0	0	0	0	0	1.0	1.0
0.03	64	100	1	0	0	0	0	0	1.0	1.0
0.1	63	100	5	0	0	0	0	0	5.0*	0

G, gaps; B, breaks; E, exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations; 4NQO, 4-nitroquinoline 1-oxide.

*Significantly different from control (P<0.05, χ²test)

Conclusions:

The ability of iodine tincture to induce chromosome aberrations in D284 cells was evaluated in a study desgin similar to OECD testing guideline 473. Iodine tincture induced chromosome aberrations (in a statistically significant manner) only at the highest dose after 30 h of treatment without metabolic activation in D284 cells.

Executive summary:

The ability of iodine tincture to induce chromosome aberrations in D284 cells was evaluated in a study desgin similar to OECD testing guideline 473. In a first assay, D284 cells were treated for 3 h with the agent and then incubated for a further 27 h. In the second experiment, D284 cells were treated continously for 30h. In both cases, three hours before harvest, cells were treated with Colcemid and metaphase chromosome were prepared. Iodine tincture induced chromosome aberrations (in a statistically significant manner) only at the highest dose after 30 h of treatment without metabolic activation in D284 cells.

Reference 3

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitation: - Lower number of metaphases were scored compared to current OECD guideline. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Justification for type of information:

Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable.
Further information is included as attachment to attached background material.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

not specified

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

other: Human dental pulp cells (D824 cells)

Metabolic activation:

with and without

Metabolic activation system:

Rat liver postmitochondrial supernatant (PMS)

Test concentrations with justification for top dose:

3-h treatment assay without metabolic activation: 0.03%, 0.1%, 0.3%
30-h treatment assay without metabolic activation: 0.03%, 0.1%, 0.3%
2-h treatment with metabolic activation: 0.03%, 0.1%, 0.3%

Vehicle / solvent:

No vehicle

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

4-nitroquinoline-N-oxide

Remarks:

Experiment 1: 3h treatment without PMS

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

no

Remarks:

Experiment 2: 30h treatment without PMS

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

yes

Remarks:

PMS control

Positive controls:

yes

Positive control substance:

cyclophosphamide

Remarks:

Experiment 3: 2h treatment with PMS

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: In experiment 1, cells were treated for 3h with the agent or 4-nitroquinoline 1-oxide (4NQO) as positive control without metabolic activation. In experiment 2, cells were treated with povidone iodone for 30h without metabolic activation. In experiment 3, cells were treated for 2 hours with povidone iodine or cyclophosphamide (as positive control) and then incubated.
- Expression time (cells in growth medium): In experiment 1, cells were incubated for a further 27 h. In experiment 2, cells were continously treated with povidone iodine for 30 h. In experiment 3, cells were treated for 2 h with povidone iodine in the presence of 5% PMS or with 50 µM cyclophosphamide in the presence of PMS.


SPINDLE INHIBITOR (cytogenetic assays): Colcemid 0.02 µg/mL (GIBCO/Invitrogen, Tokyo, Japan), administered three hours before the end of the incubation period in both assays.
STAIN (for cytogenetic assays): Not reported


NUMBER OF REPLICATIONS: No data on replicates.


NUMBER OF METAPHASES EVALUATED: 100 metaphases per dose group (see result table for info on negative and positive controls).


DETERMINATION OF CYTOTOXICITY
- Method: relative cell number (number of cells treated relative to the number of cells in the control cultures x100). Briefly, D824 cells were plated in triplicate and incubated overnight. The cells were treated with povidone iodine at varying concentrations for 3 h. After washing with fresh medium, cells were incubated for a further 27 h. The number of cells was counted after harvesting with 0.25% trypsin. For the 30h experiment, cells were treated for the same period of time. To measure cytotoxicity of povidone iodine in the presence of 5% rat liver postmitochondrial supernatant (PMS) cells were treated with varying concentrations of the agent and PMS for 2h. After washings, cells were incubated for further 28h and the cells were counted.


OTHER EXAMINATIONS:
- Determination of polyploidy and endoreplication: Yes, but counted as chromosome aberrations.


OTHER: PMS was prepared from three male Sprague-Dawley rats pretreated by injection (intraperitoneal) with sodium phenobarbital at 30 mg/kg bw on day 0 and at 60 mg/kg bw at day 1, 2 and 3; 5,6-benzoflavone at 80 mg/kg bw was injected intraperitoneally on day 2. On day 4, livers were excised from the euthanised animals and were homogenized with a Brinkman Polytron in three volumes of 0.25 M sucrose at pH 7.4 containing 2mM MgCl2. and 20 mM HEPES. The PMS fraction was prepared by two successive centrifugations at 9000g for 10 min and 15000 g for 20 min. The supernatant was frozen and store in liquid nitrogen until use.


Metaphase chromosomes were prepared as described by Tsutsui et al. (Mutat. Res. 373: 113-123, 1997)

Evaluation criteria:

Statistical significance of the difference in the incidences of chromosome aberrations between control cultures and cultures treated with povidone iodine.

Statistics:

P value, χ2 test

Species / strain:

mammalian cell line, other: D824 cells

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

3 h exposure without PMS

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Untreated negative controls validity:

valid

Positive controls validity:

valid

Species / strain:

mammalian cell line, other: D824 cells

Metabolic activation:

without

Genotoxicity:

negative

Remarks:

30 h exposure without PMS

Cytotoxicity / choice of top concentrations:

cytotoxicity

Untreated negative controls validity:

valid

Positive controls validity:

not examined

Species / strain:

mammalian cell line, other: D824 cells

Metabolic activation:

with

Genotoxicity:

negative

Remarks:

2 h exposure with PMS

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

See tables below

Table 1: Ability of povidone-iodine tincture to induce chromosome aberrations in D824 cells treated for 3 h.

Conc. (%)	Relative cell number (%)	Number of metaphases scored (%)	Type of aberrations (%)						Aberrant metaphases (%)	Polyploidy and endoreduplication
			G	B	E	D	O	F
0	100	500	1	0	0	0	0	0	1.0	3.6
0.03	90	100	0	0	0	0	0	0	0	0
0.1	97	100	2	0	0	0	0	0	2.0	2.0
0.3	87	100	0	0	0	0	0	0	0	3.0
4NQO(µM)
0.5	59	100	7	11	1	0	0	0	19.0*	5.0
1.0	52	100	9	21	1	0	0	0	25.0*	19.0*

G, gaps; B, breaks; E, exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations; 4NQO, 4-nitroquinoline 1-oxide.

*Significantly different from control (P<0.01, χ²test)

 

Table 2: Ability of povidone-iodine tincture to induce chromosome aberrations in D824 cells treated for 30 h.

Conc. (%)	Relative cell number (%)	Number of metaphases scored (%)	Type of aberrations (%)						Aberrant metaphases (%)	Polyploidy and endoreduplication
			G	B	E	D	O	F
0	100	300	1	0	0	0	0	0	1.0	3.0
0.03	94	100	0	0	0	0	0	0	0	5.0
0.1	77	100	2	0	0	0	0	0	2.0	4.0
0.3	65	100	0	0	0	0	0	0	0	1.0

G, gaps; B, breaks; E, exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations.

 

 

Table 3: Ability of povidone-iodine tincture to induce chromosome aberrations in D824 cells treated for 2 h in the presence of rat liver PMS.

Conc. (%)	PMS (%)	Relative cell number (%)	Number of metaphases scored (%)	Type of aberrations (%)						Aberrant metaphases (%)	Polyploidy and endoreduplication
				G	B	E	D	O	F
Control	0	100	100	0	0	0	0	0	0	0	2.0
PMS Control	5	99	100	1	0	0	0	0	0	1.0	2.0
P-I 0.03	5	101	100	1	0	0	0	0	0	0	4.0
P-I 0.1	5	84	100	0	0	0	0	0	0	0	5.0
P-I 0.3	5	63	100	0	0	0	0	0	0	0	4.0
CP(µM)
50	0	78	100	0	0	0	0	0	0	0	1.0
50	5	51	100	25	15	6	0	0	0	40.0*	1.0

G, gaps; B, breaks; E, exchanges; D, dicentric chromosomes; O, ring chromosomes; F, fragmentations; CP, cyclophosphamide; PMS, postmitochondrial supernatant; P-I, povidone-iodine.

*Significantly different from control (P<0.01, χ²test)

Conclusions:

The ability of povidone iodine to induce chromosome aberrations in D284 cells was evaluated in three different experiments in a study design similar to OECD testing guideline 473. Povidone iodine did not induce chromosome aberrations in any of the tested conditions.

Executive summary:

The ability of povidone iodine to induce chromosome aberrations in D284 cells was evaluated in three different experiments in a study design similar to OECD testing guideline 473. In a first assay, D284 cells were treated for 3 h with povidone iodine without metabolic activation and then incubated for a further 27 h. In the second experiment, D284 cells were treated continously for 30h without metabolic activation. In a third experiment, D284 cells were treated with povidone iodine in the presence of 5% rat liver postmitochondrial supernatant for 2 h and then incubated for 28 h. In all cases, three hours before harvest, cells were treated with Colcemid and metaphase chromosomes were prepared. Povidone iodine did not induce chromosome aberrations with and without metabolic activation in D824 cells under testing conditions.

Reference 4

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, compared to current OECD guideline presents deficiencies: - Limited number of S. typhimurium strains - No metabolic activation assay was included - Rationale for dose selection is not reported (no information on cytotoxicity) - Tests conditions differ markedly from current guideline in second experiment with S. thyphimurium - Results are expressed as inhibition zone in E. Coli experiment - No information on replicates. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Justification for type of information:

Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable.
Further information is included as attachment to attached background material.

Qualifier:

according to guideline

Guideline:

other: B.N. Ames, in "Chemical Mutagens" vol 1, A. Hollaender, Ed. Plenum, New York, N.Y., 1971, pp 267-282

Qualifier:

according to guideline

Guideline:

other: E.E. Slater, M.D. Anderson, H.S. Rosenkranz. Cancer Res. 31, 970 (1971).

GLP compliance:

no

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium, other: TA 1530 and TA1538

Species / strain / cell type:

E. coli, other: E. Coli pol A+/A1-

Metabolic activation:

not specified

Test concentrations with justification for top dose:

Mutagenicity tests: 0.2, 2 and 20 µL of povidone-iodine solution (0.1 M in ascorbic acid) in S. typhimurium assays.
DNA modifying activity: 1, 2, 3.3, 5, 10 and 20 µL of povidone-iodine solution (0.1 M in ascorbic acid).

Vehicle / solvent:

No vehicle used

Untreated negative controls:

no

Negative solvent / vehicle controls:

yes

Remarks:

water

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Ethyl methanesulfonate, methyl methanesulfonate, β-propiolactone, 2-nitrofluorene

Remarks:

S. typhimurium experiments

Untreated negative controls:

not specified

Negative solvent / vehicle controls:

not specified

True negative controls:

not specified

Positive controls:

yes

Positive control substance:

other: Methyl methanesulfonate, β-propiolactone, Propyleneimine, chloramphenicol

Remarks:

E. Coli experiment

Details on test system and experimental conditions:

METHOD OF APPLICATION: as impregnation on paper disk

DURATION
- Exposure duration: In first experiment, plates were incubated in the dark at 37 °C for 54 h. After that time, the number of mutants and the diameter of the zones of growth inhibition were measured. In a second experiment, bacteria were chilled to 4 °C, and povidone-iodine was added. At intervals, portions of the cells were removed, the povidone-iodine was decomposed by addition of ascorbic acid (final concentration 0.1 M), and 10-fold serial dilutions of the treated cells were spread onto the surface of agar for the determination of the number of revertants to histidine independence (mutants) as well as of the number of viable cells. Plates were incubated in the dark for 54 h prior to scoring. In the DNA Modifying activity experiment, test substance was impregnated on paper disks and deposited on top of the E. Coli layer. The cultures were incubated at 37ºC for 12 h and the diameter of the zones of inhibition were measured.


SELECTION AGENT (mutation assays): Histidine free medium


NUMBER OF REPLICATIONS: Not reported

OTHER: Medium for scoring mutants consisted on minimal medium supplemented with biotin and containing a trace of histidine.

Evaluation criteria:

Number of mutants per plate and zone of inhibition

Statistics:

Not required

Species / strain:

S. typhimurium, other: TA1530 and TA1538

Metabolic activation:

not specified

Genotoxicity:

negative

Remarks:

incubated at 37 °C

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium, other: TA1530

Metabolic activation:

not specified

Genotoxicity:

positive

Remarks:

Mutagenicity was demonstrated only on strain TA1530 under special conditions (incubation at 4 °C)

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

not specified

Genotoxicity:

negative

Remarks:

Mutagenicity was demonstrated only on strain TA1530 under special conditions (incubation at 4 °C)

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

E. coli, other: E. Coli pol A+/A1-

Metabolic activation:

not specified

Genotoxicity:

other: Povidone-iodine blocked the growth of DNA polymerase-deficient E. Coli

Cytotoxicity / choice of top concentrations:

not specified

Vehicle controls validity:

not specified

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Povidone-iodine when tested following the standard procedure developed by Ames, no mutagenic activity was observed (Table 1). The known mutagens (methyl methanesulfonate, β-propiolactone, ethyl methanesulfonate and 2 -nitrofluorene) were active in the assay.

Table 1: Mutagenicity of povidone-iodine using a standard S. typhimurium assay system.

Agent	Amount (µL)	TA 1530		TA 1538
		Zone of inhibition (mm)	Mutants per plate	Zone of inhibition (mm)	Mutants per plate
Povidone-iodine	0.2	0	17	0	13
	2	11.3	16	11.5	14
	20	31.0	22	32.3	16
Ethyl methanesulfonate	10	0	8000	0	7
Methyl methanesulfonate	10	22.2	530	24.2	14
β-propiolactone	10	31.0	2652	25.9	13
2-nitrofluorene	250 µg	0	13	0	87
Water (control)	10	0	17	0	12

 

When using the modified experiment, povidone-iodine resulted active in S. typhimurium TA1530 in a concentration and time of exposure manner. Povidone-iodine had no mutagenic effect on strain TA1538. Both results are not reported in the article in a tabular way.

In the E. Coli assay, povidone-iodine, as indicated by the authors, blocked preferentially the growth of the DNA polymerase-deficient (Table 2).

Table 2: Inhibition of DNA polymerase-deficient E. Coli.

Agent	Amount (µL)	Diameter of zone of inhibition, mm
		Pol A^+	Pol A1^-
Povidone-iodine	20	73.0	>86
	10	50.6	81.4
	5	26.5	31.0
	3.3	19.2	25.6
	2	16.6	18.9
	1	14.2	15.7
Methyl methanesulfonate	10	37.4	55.1
β-propiolactone	10	36.5	58.7
Propyleneimine	10	11.5	21.5
Chloramphenicol	30 µg	31.8	31.9

Conclusions:

Povidone-iodine was not mutagenic to strain TA1530 and TA1538 following the standard procedure developed by Ames. In the second experiment under no standard conditions, povidone showed mutagenic activity in strain TA1530 but not in TA1538.

In the E.Coli DNA Modifying activity assay, the diameter of zone of inhibition was increased in a dose dependent manner, but due to lack of cytotoxicity data, it is not possible to assess whether the effect observed is due to the bactericidal properties of the test agent.

The study is deemed ambiguous due to the lack of cytotoxicity data and the biological relevance of the no standard conditions where a positive result was observed with S. typhimurium.

Executive summary:

The mutagenic potential of povidone-iodine was assessed in two mutagenicity tests. In the first experiment, a standard Ames test using S. typhimurium TA1530 and TA1538 was performed. The test substance was incorporated onto the surface of agar plates using paper disks impregnated with the test agent. The plates were incubated for 54 h at 37 ℃. A second experiment was performed using bacteria in liquid medium chilled to 4 ℃ . At intervals, portions of cells were removed and povidone iodine was decomposed. The plates were in the dark for 54 h and the number of colonies were counted.

Additionally, a DNA modifying activity was conducted with E. Coli pol A+ and pol A1 -. In this case, paper disks were impregnated with the test substance and deposited on top of the bacterial layer. The cultures were incubated at 37 ℃ for 12 h.

Povidone-iodine was not mutagenic to strain TA1530 and TA1538 following the standard procedure developed by Ames. In the second experiment under no standard conditions, povidone showed mutagenic activity in strain TA1530 but not in TA1538.

In the E.Coli DNA Modifying activity assay, the diameter of zone of inhibition was increase in a dose dependent manner, but due to lack of cytotoxicity data, it is not possible to assess whether the effect observed is due to the bactericidal properties of the test agent.

The study is deemed ambiguous due to the lack of cytotoxicity data and the biological relevance of the testing conditions where a positive result was observed with S. typhimurium.

Reference 5

Endpoint:

in vitro DNA damage and/or repair study

Remarks:

Type of genotoxicity: DNA damage and/or repair

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published literature study, guideline-comparable with limitations: - No replicates reported - No treatment with metabolic activation - No positive control - Culture conditions not reported

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 479 (Genetic Toxicology: In Vitro Sister Chromatid Exchange Assay in Mammalian Cells)

GLP compliance:

not specified

Type of assay:

sister chromatid exchange assay in mammalian cells

Species / strain / cell type:

mammalian cell line, other: Syrian hamster embryo cells

Metabolic activation:

without

Test concentrations with justification for top dose:

0, 79, 236, 473 µM

Vehicle / solvent:

- Vehicle(s)/solvent(s): DMSO (final concentration 473 mM)

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Remarks:

DMSO is widely accepted for genotoxicity tests

True negative controls:

no

Positive controls:

no

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 24 h in the presence of 5-bromodeoxyuridine (10 µg/mL) under dark conditions.


SPINDLE INHIBITOR: Colcemid (2 µg/mL), added 3 hours before harvest.
STAIN: Slides were stained for 15 min in a solution of Hoechst 33258 (50 µg/mL in water), washed, dipped in PBS(-) and exposed to UV (row of 6 F15TB/BLB fluorescent bulbs, 33 J/m2/s) for 1 hour at 55°C. The slides were then stained with 3% GIEMSA solution for 10 min.


NUMBER OF REPLICATIONS: Not reported


NUMBER OF CELLS EVALUATED: 30 per group


DETERMINATION OF CYTOTOXICITY
- Method: colony-forming efficiency. Colony forming efficiency was determined in SHE cells by treating them for 24 h at varying concentrations of iodine. After harvesting with trypsin, cells were replated in triplicateonto dishes at 2000 cells/dish and incubated for 7 days. The relative colony-forming efficiency was expressed as the number of colonies in the treated dishes divided by the number in the control dishes x100.

Evaluation criteria:

Statistical comparison to control values

Statistics:

P value, Student t test

Species / strain:

mammalian cell line, other: Syrian hamster embryo cells

Metabolic activation:

without

Genotoxicity:

positive

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

not examined

Table 1: The ability of iodine to induce sister-chromatid exchange in SHE cells.

Conc. (µM)	Relative colony forming efficiency (%)	SCEs/cell
0	100	8.03± 3.54
79	91	11.63 ± 4.60*
236	90	12.67 ± 4.24*
473	47	13.80 ± 3.81*

* Significantly different from control (P<0.01, Studentttest) (n=30)

Conclusions:

The ability of iodine to induce sister-chromatid exchange were examined using Syrian hamster embryo cells in a testing design similar to OECD tsting guideline 479. Sister-chromatid exchanges were induced by iodine in Syrian hamster embryo cells under testing conditions

Executive summary:

The ability of iodine to induce sister-chromatid exchange were examined using Syrian hamster embryo cells in a testing design similar to OECD tsting guideline 479. SHE cells were treated at varying concentrations of iodine for 24 h in the presence of 5 -bromodeoxyuridine under dark conditions. Sister chromatids were differentially stained and thirty second-division metaphases with diploid number of chromosomes were analyzed for sister-chromatid exchange frequency. Sister chromatid exchanges were induced by iodine (p < 0.01) in concentration-dependent manner.

Reference 6

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - No assay with metabolic activation was performed. - Number of concentrations tested lower than recommended by current OECD guideline. - Limited data on cytotoxicity results is reported. - No independent repeat to confirm negative result.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

not specified

Type of assay:

mammalian cell gene mutation assay

Target gene:

TK (+/-)

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

The L5178Y cell line used in our studies was kindly supplied by Food and Drug Administration, Washington, D.C.. The cells were maintained in logarithmic growth by dilution three times a week to 3E+5 cells/mL with Fisher's Medium for Leukemic Mice (FMp), supplemented with 10% horse serum and 1% 200 mM glutamine (FM10) (Grand Island Biological Company, Grand Island, N.Y.). The cells were grown on a rocker platform (Bellco, Vineland, NJ.).
The cell lines were maintained at 37℃ in a humidified CO2 incubator.

Metabolic activation:

without

Test concentrations with justification for top dose:

22, 43, 85, 170 and 340 µg/mL

Vehicle / solvent:

No vehicle

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Remarks:

not required

True negative controls:

no

Positive controls:

yes

Positive control substance:

ethylmethanesulphonate

Remarks:

A second positive control was also used: N-methyl-N-nitro-N-nitrosoguanidine

Details on test system and experimental conditions:

Mutagenicity was assessed using a modification of the technique developed by Clive and Spector (Mutat. Res. 31: 17-29, 1975).

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4 hours (37 ºC)
- Expression time (cells in growth medium): 48 hours
- Selection time (if incubation with a selection agent): 10 days (37 ºC)


SELECTION AGENT (mutation assays): 5-bromo-2'-deoxy-uridine (BUdR)


NUMBER OF REPLICATIONS: 6


DETERMINATION OF CYTOTOXICITY
- Method: Cell viability (trypan blue exclusion dye and by measurement of the cellular time). Dose level which resulted in 50% cell viability was used as highest in mutagenicity test.

Evaluation criteria:

The number of mutant colonies/1E+5 cells was designated as having a mutational frequency (MF) of one. Mutational values of each respective dose were compared to the control value. A mutational frequency of 2.5 or greater was considered a positive mutational event.

Statistics:

Not required (except for positive controls, which were compared by using P value, student's T-Test).

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Untreated negative controls validity:

valid

Positive controls validity:

valid

At doses tested, iodine did not induce significantly alter the mutation frequency in the mouse lymphoma assay (Table 1).

 

Table 1: Mutagenicity of iodine in the L5178Y test system.

Substance	Concentration (µg/mL)	Mutational Frequency (MF)
Iodine	340	0.76
	170	1.09
	85	2.0
	43	0.84
	22	0.67
Media	-	1.0*
EMS	500	12.0**
MNNG	5	15.0**

EMS: Ethyl methanesulfonate; MNNG: N-methyl-N-nitro-N-nitrosoguanidine.

* Actual MF for media control before normalization to 1 was 4E-5mutants

** Statistical significance at levels of p<0.05

Conclusions:

The mutagenic potential of Iodine (I2) was studied using the L5178Y mouse (TK +/-) lymphoma assay in a study design similar to OECD testing guideline 476. Iodine did not showed biologically significant mutagenic ability under testing conditions.

Executive summary:

The mutagenic potential of Iodine (I₂) was studied using the L5178Y mouse (TK +/-) lymphoma assay in a study design similar to OECD testing guideline 476. Cells were incubated with the test compound for four hours at 37°C. The cells were then washed and incubated for additional 48 h to allow the expression of induced mutations. The cells were plated in Fishers Medium with 20% horse serum and in the presence of BUdR. Colony formation was scored after 10 days of incubation at 37°C.

All concentrations of iodine were inactive. In conclusion, iodine did not exert a biologically significant mutagenic ability in the mouse (TK +/-) lymphoma assay in vitro under tested conditions.

Reference 7

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - Number of concentrations tested lower than recommended by current OECD guideline. - Limited data on cytotoxicity results is reported. - No independent repeat to confirm negative result. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable-

Justification for type of information:

Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable.
Further information is included as attachment to attached background material.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

not specified

Type of assay:

mammalian cell gene mutation assay

Target gene:

TK (+/-)

Species / strain / cell type:

mouse lymphoma L5178Y cells

Details on mammalian cell type (if applicable):

The L5178Y cell line used in our studies was kindly supplied by Food and Drug Administration, Washington, D.C.. The cells were maintained in logarithmic growth by dilution three times a week to 3E+5 cells/mL with Fisher's Medium for Leukemic Mice (FMp), supplemented with 10% horse serum and 1% 200 mM glutamine (FM10) (Grand Island Biological Company, Grand Island, N.Y.). The cells were grown on a rocker platform (Bellco, Vineland, NJ.).
The cell lines were maintained at 37℃ in a humidified CO2 incubator.

Metabolic activation:

with and without

Metabolic activation system:

S9 fraction of liver microsomes

Test concentrations with justification for top dose:

Experiment 1 (No metabolic activation): 10 mg/mL, 5 mg/mL, 1 mg/mL, 500 µg/mL and 100 µg/mL
Experiment 2 (with metabolic activation): 10 mg/mL, 5 mg/mL and 1 mg/mL

Vehicle / solvent:

No vehicle (dissolved in media)

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Remarks:

not required

True negative controls:

no

Positive controls:

yes

Positive control substance:

N-dimethylnitrosamine

Remarks:

A second positive control was also used: N-methyl-N-nitro-N-nitrosoguanidine

Details on test system and experimental conditions:

Mutagenicity was assessed using a modification of the technique developed by Clive and Spector (Mutat. Res. 31: 17-29, 1975).

METHOD OF APPLICATION: in medium

DURATION
- Exposure duration: 4 hours (37 ºC)
- Expression time (cells in growth medium): 48 hours
- Selection time (if incubation with a selection agent): 10 days (37 ºC)


SELECTION AGENT (mutation assays): 5-bromo-2'-deoxy-uridine (BUdR)


NUMBER OF REPLICATIONS: 6


DETERMINATION OF CYTOTOXICITY
- Method: Cell viability (trypan blue exclusion dye and by measurement of the cellular time). Dose level which resulted in 50% cell viability was used as highest in mutagenicity test.

Evaluation criteria:

The number of mutant colonies/1E+5 cells was designated as having a mutational frequency (MF) of one. Mutational values of each respective dose were compared to the control value. A Mutational frequency of 2.5 or greater was considered a positive mutational event.

Statistics:

Statistically significance using P value.

Species / strain:

mouse lymphoma L5178Y cells

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Untreated negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: all strains/cell types tested

Povidone-iodine (PVP-I) at doses tested did not significantly alter the mutational frequency in the absence of metabolic activation (Table 1). In the same assay, both positive controls exhibited a significant mutagenic actional.

In the presence of metabolic activation, PVP-I produced a mutational frequency over 2.5, only at 5 mg/mL was the mutational frequency statistically significant from control values. The significance of the response with PVP-I at 10 mg/mL was difficult to assess due to high cytotoxicity (92% morbidity by trypan blue exclusion) was reported by the authors. Both positive controls (MNNG and DMN), were found to be potent mutagens. DMN was inactive in the absence of the S-9 fraction. The S-9 fraction alone had no effect on the mutational frequency.

Table 1: Mutagenicity of PVP-I in the L5178Y test system.

Substance	Concentration	Mutational Frequency (MF)
PVP-I	10 (mg/mL)	2.33
	5 (mg/mL)	0.93
	1 (mg/mL)	0.75
	500 (µg/mL)	0.82
	100 (µg/mL)	0.75
Media	-	1.0*
EMS	500(µg/mL)	12.0**
MNNG	5 (µg/mL)	15.0**

EMS: Ethyl methanesulfonate; MNNG: N-methyl-N-nitro-N-nitrosoguanidine.

* Actual MF for media control before normalization to 1 was 4E-5 mutants

** Statistical significance of levels of p<0.05

Table 2: Mutagenicity of PVP-I in the L5178Y test system with S-9 microsomal activation.

Substance	Concentration	Mutational Frequency (MF)
PVP-I + S-9^5	10 (mg/mL)	3.20
	5 (mg/mL)	4.74^1
	1 (mg/mL)	1.90
DMN	3.70 (mg/mL)	1.22
DMN + S-9	3.70 (mg/mL)	25^2
MNNG	5 (µg/mL)	3.98^3
Media		1.0^4
Media + S-9		1.0^4

DMN: Dimethylnitrosamine; MNNG: N-methyl-N-nitro-N-nitrosoguanidine; S-9: Aroclor 1254 activated rat liver microsomal homogenate.

1 Statistical significance at levels of p<0.01

2 Statistical significance at levels of p<0.01

3 Statistical significance at levels of p<0.001

4 MF for media control before normalization to 1 was 4 E-5 mutants 

MF for media +S-9 before normalization was 6E-5mutants

520 µL of S-9 used per test sample 

Conclusions:

The mutagenic potential of povidone-iodine (PVP-I) was studied using the L5178Y mouse (TK +/-) lymphoma assay in a study dsign similar to OECD testing guideline 476. Povidone-iodine (PVP-I) did not show biologically significant mutagenic ability under testing conditions.

Executive summary:

The mutagenic potential of povidone-iodine (PVP-I) was studied using the L5178Y mouse (TK +/-) lymphoma assay in a study dsign similar to OECD testing guideline 476. Cells were incubated with the test compound for four hours at 37 °C in the presence and absence of metabolic activation. The cells were then washed and incubated for additional 48 h to allow the expression of induced mutations. The cells were plated in Fishers Medium with 20% horse serum and in the presence of BUdR. Colony formation was scored after 10 days of incubation at 37 °C.

All concentrations of PVP-I were inactive in the absence of S-9 microsomal activation system. In the presence of S-9 fraction, PVP-I had only marginal activity as mutagen.

It was concluded that PVP-I did not possess any biologically significant mutagenic ability in the mouse (TK +/-) lymphoma assay in vitro under tested conditions.

Reference 8

Endpoint:

in vitro DNA damage and/or repair study

Remarks:

Type of genotoxicity: DNA damage and/or repair

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Published literature study, guideline-comparable with limitation: - Less cultures than recommended by current OECD guideline. - No positive control. - No assay with metabolic activation. - No second independent repeat for confirmation of the result.

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 482 (Genetic Toxicology: DNA Damage and Repair, Unscheduled DNA Synthesis in Mammalian Cells In Vitro)

GLP compliance:

not specified

Type of assay:

other: DNA damage and repair assay, unscheduled DNA synthesis in mammalian cells in vitro

Species / strain / cell type:

mammalian cell line, other: Syrian hamster embryo cells

Metabolic activation:

without

Test concentrations with justification for top dose:

3, 30, 300 µg/mL

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

not specified

True negative controls:

no

Positive controls:

no

Details on test system and experimental conditions:

METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: One hour in culture media
- Expression time (cells in growth medium): Six hours in 1mM hydroxyurea culture medium containing 370 KBq/mL [3H] thymidine.

Cells were washed with phosphate buffered saline (PBS) at 4 °C and were treated with 5% trichloro-acetate (TCA) at 4°C. 5% TCA was replaced 2-3 times at 1-2 hour interval. At the end cells were washed and dried. The cover slips were individually put into a scintillation vial containing toluene scintillater. The amount of [3H] thymidine collected which was not soluble in acid was measured in a liquid scintillation counter.


NUMBER OF REPLICATIONS: 4 cultures.


DETERMINATION OF CYTOTOXICITY
- Method: Cell survival rates.

Cells were put into solutions with a predetermined concentration of the test substance and left to react for 48 h. The cells were then washed with PBS twice and treated with trypsin to make a solution with cells. 2000 cells were plated onto four Petri dishes. After one week incubation, cells in the Petri dishes were washed with physiological saline and fixed with methyl alcohol before staining with Giemsa. Number of generated colonies were counted under a microscope. The cell survival rate was expressed as a percentage of a number of colonies in a treated group in comparison to the control group.

Evaluation criteria:

Statistical difference from control

Statistics:

P values and Student t test

Species / strain:

mammalian cell line, other: Syrian hamster embryo (SHE) cells

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

not applicable

True negative controls validity:

not applicable

Positive controls validity:

not examined

Table 1: Relative survival of SHE cells treated with iodine.

Concentration (µg/mL)	Relative cell survival (%)*
50	95.5 ± 10.7
100	91.3 ± 11.2
150	61.7 ± 7.1 **

* Mean ± S.D. of 4 dishes.

** Significantly different from control (P<0.01,ttest)

 

Table 2: Unscheduled DNA Synthesis (UDS) in SHE cells treated with iodine.

Concentration (µg/mL)	Induced UDS*
3	0
30	0
300	84.6 ± 9.9

* Mean ± S.D. of 4 cultures.

Conclusions:

The ability of iodine to induce Unscheduled DNA synthesis (UDS) was examined in Syrian hamster embryo (SHE) cells in a study design simliar to OCD testing guidline 482. Iodine did not induce a statistically significant level of unscheduled DNA synthesis in SHE cells under testing conditions.

Executive summary:

The ability of iodine to induce Unscheduled DNA synthesis (UDS) was examined in Syrian hamster embryo (SHE) cells in a study design simliar to OCD testing guidline 482. SHE cells were treated with iodine for 1h and then incubated for six in hydroxyurea culture medium containing [3H] thymidine. The uptake of [3H] thymidine was measured in a liquid scintillation counter. Iodine did not induce a statistically significant level of unscheduled DNA synthesis in SHE cells under testing conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Iodine and chemically related compounds have been tested for genotoxicity in a variety of systems both in vitro and in vivo (See Additonal information box, Table 1). Based on release of iodine (I₂) and similar mode of action, mutagenicty data from the iodine, iodine tincture and PVP-I are considered interchangeable.

Therefore, based on the overall weight of evidence for in vivo genotoxicity, the conclusion for germ cell and somatic gene mutation is negative.

Link to relevant study records

Reference

Reference 1

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - No positive control used - Sampling time was not at recommended by current OECD guideline - Lack of well documented rationale to confirm toxicity/availability in the target tissue - No data on mitotic index. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

GLP compliance:

no

Type of assay:

mammalian bone marrow chromosome aberration test

Species:

hamster, Chinese

Strain:

other: Gricetulus griseus

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Thomae Co., Biberach, Federal Republic of Germany
- Age at study initiation: Not reported
- Weight at study initiation: Not reported
- Assigned to test groups randomly: Not reported
- Fasting period before study: Not reported
- Housing: Plastic (polycarbonate) cages
- Diet: Standardized feed (Altromin R supplied by Altromin Co. Lage/Lippe, Federal Republic of Germany or Ssniff H supplied by Intermast GmbH, Boeckum-Hoevel, Federal Republic of Germany), Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 2
- Humidity (%): 55 ± 5
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12 h light/12 h dark

Route of administration:

intraperitoneal

Vehicle:

- Solvent used: water

Duration of treatment / exposure:

Experiment 1: Single intraperitoneal administration (2 different doses: 38.3 or 82.5 mg/kg)
Experiment 2: Five intraperitoneal injections of one dose level 38.3 mg/kg

Frequency of treatment:

In experiment 2, the intraperitoneal injections were administered in a 24-h interval

Post exposure period:

Experiment 1: Animals were sacrificed at 6, 24 and 48 after the single application
Experiment 2: Animals were sacrificed 6 hours after last application

Dose / conc.:

38.3 mg/kg bw/day (actual dose received)

Remarks:

Single or five applications

Dose / conc.:

82.5 mg/kg bw/day (actual dose received)

Remarks:

Single application

No. of animals per sex per dose:

6 male and 6 female per group

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Positive control(s):

No positive control was used

Tissues and cell types examined:

Metaphases from bone marrow

Details of tissue and slide preparation:

No further details reported

Evaluation criteria:

Statistical comparison to control

Statistics:

Significant differences were checked using chi-square or U test

Sex:

male/female

Genotoxicity:

negative

Toxicity:

yes

Remarks:

repeated application caused the animals to show signs of pain lasting for ~1 min.

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

not examined

There was no increase in the percentage of aberrant metaphases when the substance was administered singly (Table 1) or repeatedly (Table 2). The animals tolerated povidone-iodine with no symptoms when administered in a single dose, but repeated application caused the animals show signs of pain lasting for approximately 1 min.

Table 1: Testing povidone-iodine in the bone marrow test on Chinese Hamster with single intraperitoneal injection

Dose	Untreated			10 mL of saline/kg			38.3 mg/kg			82.5 mg/kg
Put to death (h)	6	24	48	6	24	48	6	24	48	6	24	48
No of animals	12	11	12	12	12	12	12	11	12	12	12	12
Analyzed metaphases	1200	1100	1200	1200	1200	1200	1200	1100	1200	1200	1200	1200
Animals with aberrant metaphases	8	8	9	7	9	6	9	8	8	6	9	9
Metaphases with aberrations
Including gaps	16	12	18	11	22	11	18	23	15	12	20	21
Excluding gaps	3	4	2	2	2	2	4	5	2	2	2	5
Gaps (chromatide)	9	8	14	7	15	9	10	15	10	7	12	16
Gaps (isochromatide)	4	0	2	2	5	0	4	3	3	3	6	0
Breaks (chromatide)	0	2	1	1	0	2	2	2	2	1	0	2
Breaks (isochromatide)	0	0	0	0	1	0	0	0	0	0	0	0
Acentric fragments	3	1	1	0	1	0	2	3	0	1	1	3
Multiple aberrations	0	1	0	1	0	0	0	0	0	0	1	0

Table 2: Testing povidone-iodine in the bone marrow test on Chinese Hamster with five intraperitoneal injection

Dose	Untreated	5 x 10 mL of saline/kg	5 x 38.3 mg/kg
No of animals	12	11	11
Analyzed metaphases	1200	1100	1100
Animals with aberrant metaphases	7	8	7
Metaphases with aberrations
Including gaps	10	25	13
Excluding gaps	2	7	2
Gaps (chromatide)	8	17	8
Gaps (isochromatide)	0	1	3
Breaks (chromatide)	1	6	2
Breaks (isochromatide)	0	0	0
Acentric fragments	0	1	0
Multiple aberrations	1	0	0

Conclusions:

Povidone-iodine USP was tested for genotoxic potential in Chinese Hamsters by the in vivo chromosome aberrations assay in the bone marrow in a study design similar to OECD testing guideline 475. Under testing conditions, povidone-iodine did not induce chromosome aberrations in the bone marrow of Chinese Hamster.

Executive summary:

Povidone-iodine USP was tested for genotoxic potential in Chinese Hamsters by the in vivo chromosome aberrations assay in the bone marrow in a study design similar to OECD testing guideline 475.

To assess this potential, two experiments were carried out. In the first one, male and female hamsters were administered by single peritoneal injection with test compound, distilled water and a third group remained untreated. Animals were sacrificed after 6, 24 and 48 h post administration. In a second experiment, male and female hamsters were injected five times with a daily interval and sacrificed 6 hours after the last application. 100 metaphases per animal were examined for gaps, breaks and fragments.

There was no increase in the percentage of aberrant metaphases when the substance was administered singly or repeatedly. In conclusion, povidone-iodine did not induce chromosome aberrations in the bone marrow of Chinese Hamster, under testing conditions.

Reference 2

Endpoint:

in vivo mammalian germ cell study: cytogenicity / chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - No positive control used nor historical data presented. - Only one dose level used with no detailed rationale on dose selection. - Mating schedule was not as recommended by current OECD guideline. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 478 (Genetic Toxicology: Rodent Dominant Lethal Test)

GLP compliance:

no

Type of assay:

rodent dominant lethal assay

Species:

mouse

Strain:

NMRI

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Wiga Co., Sulzfeld, Federal Republic of Germany
- Age at study initiation: Not reported
- Weight at study initiation: Not reported
- Assigned to test groups randomly: Not reported
- Fasting period before study: Not reported
- Housing: Plastic (polycarbonate) cages
- Diet: Standardized fed (Altromin R supplied by Altromin Co. Lage/Lippe, Federal Republic of Germany or Ssniff H supplied by Intermast GmbH, Boeckum-Hoevel, Federal Republic of Germany), Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 2
- Humidity (%): 55 ± 5
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12 h light/12 h dark

Route of administration:

intraperitoneal

Vehicle:

- Solvent used: water

Duration of treatment / exposure:

Single intraperitoneal administration

Frequency of treatment:

Single intraperitoneal administration

Post exposure period:

Matings in week 1, 2, 3, 4, 5, 6, 7 and 8

Dose / conc.:

72 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

20 male mice

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Positive control(s):

No positive control used

Tissues and cell types examined:

Implantations (total), live embryos and dead implantations

Details of tissue and slide preparation:

No details reported

Evaluation criteria:

Mutagenicity index

Statistics:

Significant differences were checked using chi-square or U test

Sex:

male

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

not examined

The animals tolerated a single application of povidone-iodine without symptoms. The conception rate decreased significantly during the last week, but the average number of implantations and the mutagenicity index were not affect During the other mating periods, all parameters varied in a similar manner as in the control animals (Table 1).

Table 1: Testing of povidone-iodine in the dominant lethal test on male NMRI mice when applied a single intraperitoneal dose.

		Females with implantations		Total implantations		Live embryos		Dead implantations		Mutagenicity index
Dose	Mating week	No	%	No	Per female	No	Per female	No	Per female
0	1	48	80.0	548	11.4	491	10.2	57	1.2	10.4
	2	58	96.7	771	13.3	705	12.2	66	1.1	8.6
	3	58	96.7	750	12.9	690	11.9	60	1.0	8.0
	4	56	93.3	734	13.1	671	12.0	63	1.1	8.6
	5	57	95.0	737	12.9	666	11.7	71	1.2	9.6
	6	58	96.7	736	12.7	655	11.3	81	1.4	11.0
	7	58	96.7	761	13.1	705	12.2	56	1.0	7.4
	8	54	90.0	731	13.5	652	12.1	79	1.5	10.8
10 mg/kg distilled water	1	43	71.7	516	12.0	473	11.0	43	1.0	8.3
	2	54	90.0	721	13.4	652	12.1	69	1.3	9.6
	3	57	95.0	717	12.6	646	11.3	71	1.2	9.9
	4	56	93.3	761	13.6	671	12.0	90	1.6	11.8^a
	5	59	98.3	776	13.2	699	11.8	77	1.3	9.9
	6	58	96.7	802	13.8	716	12.3	86	1.5	10.7
	7	60	100.0	772	12.9	716	11.9	56	0.9	7.3
	8	56	93.3	779	13.9	712	12.7	67	1.2	8.6
72 mg/kg povidone-iodine	1	33	55.0^b	345	10.5	296	9.0	49	1.5	14.2
	2	58	96.8	772	13.3	695	12.0	77	1.3	10.0
	3	59	98.3	735	12.5	653	11.1	82	1.4	11.2
	4	58	96.7	772	13.3	716	12.3	56	1.0	7.3
	5	59	98.3	784	13.3	719	12.2	65	1.1	8.3
	6	58	96.7	811	14.0	744	12.8	67	1.2	8.3
	7	56	93.3	679	12.1	607	10.8	72	1.3	10.6^a
	8	57	95.0	749	13.1	674	11.8	75	1.3	10.0

(a) p< 0.05; (b) p< 0.01

Conclusions:

The potential genotoxicity of Povidone-iodine was evaluated in the Dominant Lethal Test in a study design similar to OECD testing guideline 478. Povidone-iodine was not genotoxic in the Dominant Lethal Assay under testing conditions.

Executive summary:

The potential genotoxicity of Povidone-iodine was evaluated in the Dominant Lethal Test in a study design similar to OECD testing guideline 478. The assay is an indirect method for detecting effects on the germinal tissue of the tested species. Dominant lethals are generally recognized to be the result of chromosome aberrations, but gene mutations and toxic effects cannot be excluded.

In this assay, 20 male mice were administered 72 mg/kg povidone-iodine as a single peritoneal administration. Males were mated sequentially to three untreated females. After sacrifice of the females, the conception rate, total number of implantations, live embryos and dead implantations were counted.

The conception rate decreased significantly during the last week, but the average number of implantations and the mutagenicity index were not affected. During the other mating periods, all parameters varied in a similar manner as in the control animals.

It was concluded that povidone-iodine did not induce a genotoxic effect on mice in the dominant lethal test under described conditions.

Reference 3

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Published literature study, guideline-comparable with limitations: - No positive control used - Samples taken earlier than recommended by current OECD guideline - No repeat to confirm negative result - Lack of PCEs/NCEs ratio - Lack of well documented rationale to confirm toxicity/availability in the target tissue. - Based on a similar mode action, release of iodine (I2), data from the iodine, iodine tincture and PVP-I is considered interchangeable

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)

GLP compliance:

no

Type of assay:

mammalian erythrocyte micronucleus test

Species:

mouse

Strain:

NMRI

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Wiga Co., Sulzfeld, Federal Republic of Germany
- Age at study initiation: Not reported
- Weight at study initiation: Not reported
- Assigned to test groups randomly: Not reported
- Fasting period before study: Not reported
- Housing: Plastic (polycarbonate) cages
- Diet: Standardized fed (Altromin R supplied by Altromin Co. Lage/Lippe, Federal Republic of Germany or Ssniff H supplied by Intermast GmbH, Boeckum-Hoevel, Federal Republic of Germany), Ad libitum
- Water (e.g. ad libitum): Ad libitum
- Acclimation period: Not reported

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20 ± 2
- Humidity (%): 55 ± 5
- Air changes (per hr): Not reported
- Photoperiod (hrs dark / hrs light): 12 h light/12 h dark

Route of administration:

intraperitoneal

Vehicle:

- Solvent used: water

Duration of treatment / exposure:

Double intraperitoneal application

Frequency of treatment:

Double intraperitoneal application in a 24-h interval

Post exposure period:

6 h after last dose, animals were sacrificed

Dose / conc.:

36 mg/kg bw/day (actual dose received)

No. of animals per sex per dose:

10 animals per group (five male and five female)

Control animals:

yes, concurrent no treatment

yes, concurrent vehicle

Positive control(s):

No positive control used

Tissues and cell types examined:

Normochromatic (4000 per animal) and polychromatid (2000 per animal) erythrocytes from bone marrow (femurs) were examined

Details of tissue and slide preparation:

No further details on smear preparations

Evaluation criteria:

Statistical significance compared to control

Statistics:

Significant differences were checked using chi-square or U test

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

valid

Negative controls validity:

valid

Positive controls validity:

not examined

The animals tolerated administration of povidone-iodine without symptoms. There was merely a slight increase in polychromatic erythrocytes containing micronuclei, but even the increase was within the normal range.

Table 1: Testing of povidone-iodine in the micronucleus

Dose	0	2 x 10 mL distilled water/kg	2 x 36 mg PVP-I/kg
Number of animals	10	10	10
Analyzed normochromatic erythrocytes	40,000	40,000	40,000
With MN (%)	2.15	3.17	2.52
Minimum (%)	0.12	0.12	0.15
Maximum (%)	0.35	0.45	0.35
1 MN (%)	1.90	2.82	2.35
2 MN (%)	0.22	0.30	0.15
3 MN (%)	0.00	0.05	0.00
More than 3 MN (%)	0.02	0.00	0.02
Analyzed polychromatic erythrocytes	20,000	20,000	20,000
With MN (%)	3.70	2.95	4.30 (a)
Minimum (%)	0.20	0.20	0.20
Maximum (%)	0.50	0.50	0.65
1 MN (%)	3.60	2.75	4.20
2 MN (%)	0.10	0.20	0.05
3 MN (%)	0.00	0.00	0.05
More than 3 MN (%)	0.00	0.00	0.00

MN: Micronucleus(ei); PVP-I: Povidone-iodine.

(a) p< 0.05

Conclusions:

Povidone-iodine was tested for genotoxicity in mice by the micronucleus test in a study design similar to OECD testing guideline 474. Povidone-iodine did not induce significant increase in frequency of micronucleated cells in bone marrow erythrocytes under testing conditions.

Executive summary:

Povidone-iodine was tested for genotoxicity in mice by the micronucleus test in a study design similar to OECD testing guideline 474.

Three groups of 10 animals (5 male and 5 females) were used, one group received 36 mg povidone-iodine/kg (one-tenth LD50), another group received 10 mL of distilled water/kg twice at an interval of 24 h. The third group of animals remained untreated. Six hours after the final dose, the animals were sacrificed, the femurs were removed and bone marrow smears were prepared. Normochromatic and polychromatic erythrocytes were examined for the frequency of micronucleated cells. There was merely a slight increase in polychromatic erythrocytes containing micronuclei, but even this increase was within the normal range.

The findings indicated that povidone-iodine was not genotoxic by the micronucleus test in somatic cells under testing conditions.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

Iodine is a well-known micronutrient that is essential for the synthesis of thyroid hormones in all vertebrates, as well as a promoter of metamorphosis or transformation of life stages in several invertebrates. Iodine and iodide compounds have been reported to be non-genotoxic in expert reviews (EVM, 2002; WHO, 2009, WHO 2020). In the registration dossier of iodine (including PVP-iodine) as an active substance for biocidal products (Ref: Assessment report, Iodine (including PVP-iodine) Product types 1, 3, 4, 22, 13 December 2013, Sweden), it was concluded that no genotoxic potential of iodine could be identified  based on the available in vitro and in vivo data package and an overall weight of evidence assessment.

It has been reported (Hincal 2009) that severe iodine deficiency may impair thyroid hormone synthesis and cause a compensatory increase in hydrogen peroxide concentration in thyrocytes. This increase may result in a more prolonged exposure to oxygen-free radicals, which in turn may lead to DNA damage and induce mutations.

 

Iodine and chemically related compounds have been tested for genotoxicity in a variety of systems both in vitro and in vivo (Table 1). For this endpoint, data from iodine, iodine tincture and polyvinylpyrrolidone-iodine complex (PVP-I) has been assessed. PVP-I is a complex of polyvinylpyrrolidone (povidone) and iodine, designed to be a stable form of complexed iodine. 9-12 % available iodine is present in standard United States Pharmacopoeia (USP) preparations. PVP-I is used in surface disinfection but is also used extensively in antiseptic preparations of iodine as well as in drug and other applications leading to direct human contact/intake. No consistent or relevant toxic effects in humans have been reported with PVP-I. Iodine tincture is a mixture containing 2 % iodine and 2.0 % sodium iodide in 50% alcohol and is also available as strong iodine tincture (7 % iodine and 5 % KI in 83 % ethanol). There are no reports on the genotoxicity of potassium iodide and on the classification of ethanol under the criteria applied for classification and labelling of chemicals. Both PVP-I and iodine tincture act by releasing iodine to the surrounding medium, thus the potential genotoxic activity may result from the available iodine.

Table 1: Summary of available genotoxicity studies for iodine and chemically related compounds

Refererence (Reliability)	Assay/Condition	Result/Test compound
Wlodowski et al., 1975. (3)	Gene mutation bacteria/In vitro	Equivocal/PVP-I
Hori et al., 2007. (2)	Chromosome aberrations/In vitro	Positive/Iodine tincture
Hori et al., 2007. (2)	Chromosome aberrations/In vitro	Negative/PVP-I
Hikiba et al., 2005. (2)	Chromosome aberrations/In vitro	Positive/Iodine
Miyachi and Tsutsui, 2005. (2)	Sister chromatid exchanges/In vitro	Positive/Iodine
Yamamoto and Tsutsui, 2005. (2)	Unscheduled DNA synthesis/In vitro	Negative/Iodine
Kessler et al., 1980. (2)	Gene mutation in mamm. cells/In vitro	Negative/PVP-I
Kessler et al., 1980. (2)	Gene mutation in mamm. cells/In vitro	Negative/Iodine
Merkle and Zeller, 1979. (2)	Dominant Lethal Assay/In vivo	Negative/PVP-I
Merkle and Zeller, 1979. (2)	Bone marrow micronucleus test/In vivo	Negative/PVP-I
Merkle and Zeller, 1979. (2)	Bone marrow chromosome aberrations test/In vivo	Negative/PVP-I

Hincal (2009), reported that severe iodine deficiency may impair thyroid hormone synthesis and cause a compensatory increase in hydrogen peroxide concentration in thyrocytes. This increase may result in a more prolonged exposure to oxygen-free radicals, which in turn may lead to DNA damage and induce mutations.

 

Wlodowski et al. (1975) reported that povidone-iodine (PVP-I) was mutagenic in the TA1530 but not in the TA1538 tester strains of Salmonella typhimurium. The positive findings, however, were encountered under unusual temperature conditions (at 4 °C, and not the usual 37 °C in current standards). Also, the applicability of a bacterial system to evaluate the mutagenicity of a bactericide agent remains questionable. Povidone-iodine and iodine were negative in the L5178Y mouse lymphoma assay in the absence of metabolic activation and in the presence of metabolic activation, povidone-iodine showed only marginal activity.

 

Cytogenicity assays in vitro are consistent with a potential positive effect of iodine, however, it is suggested that iodine may induce chromosome damage by secondary mechanisms associated to cytotoxicity, but not as a result of DNA damage. In vitro mammalian tests have raised concern for the high rate of false positive results obtained with cytotoxic chemicals (Kirkland et al., 2007; Pfuhler et al., 2010). Iodine is in fact a high oxidizing agent which can react with proteins leading to high cytotoxicity in vitro. This hypothesis could be proven by the lack of cytogenotoxicity of PVP-I.

 

Doses of 72 mg/kg be povidone iodine (given by i.p. injection) were not mutagenic in the mouse dominant lethal assay (Merkle and Zeller, 1979). Povidone-iodine was also tested in mouse micronucleus assay and was negative at doses of 35 mg/kg bw (i.p) and did not produce chromosome aberrations in the in the bone marrow of Chinese hamsters given i.p. doses of 38.3 and 82.5 mg/kg bw, one quarter and one half of the LD50 respectively.

 

Although positive results are available for iodine in in vitro cytogenetic assays, in vivo results in both somatic (micronucleus and chromosome aberrations tests) and germ cells (dominant lethal test) indicate that iodine can be regarded as a non genotoxic substance. Based on the overall package provided and the fact that in vivo studies are more biologically relevant to humans, no additional studies are considered necessary.

References (not summarized in this section of the IUCLID File):

- Expert Group on Vitamins and Minerals (EVM). Revised review of iodine. 2002.

- Hincal, F. Oxidative damage in iodine deficiency. In: “Comprehensive handbook of iodine: nutritional, biochemical, pathological and therapeutic aspects”. USA, 2009.

- Kirkland, D., Pfuhler, S., Tweats, D., Aardema, M., Corvi, R., Darroudi, F., Elhajouji, A., Glatt, H., Hastwell, P., Hayashi, M., Kasper, P., Kirchner, S., Lynch, A., Marzin, D., Maurici, D., Meunier, J-R., Muller, L., Nohynek, G., Parry, J., Parry, E., Thybaud, V., Tice, R., van Benthem, J., Vanparys, P., White, P. 2007. How to reduce false positive results when undertaking in vitro genotoxicity testing and thus avoid unnecesary follow-up animal tests: Report of an ECVAM Workshop. Mutat. Res. 628: 31 -55.

- Pfuhler, S., Kirst, A., Aardema, M., Banduhn, N., Goebel, C., Araki, D., Costabel-Farkas, Dufour, E., Fautz, R., Harvey, J., Hewitt, N., Hibatallah, J., Carmichael, P., Macfarlane, M., Reisinger, K., Rowland, J., Schellauf, F., Schepky, A., Scheel, J. 2010. A tiered approach to the use of alternatives to animal testing for the safety assessment of cosmetics: Genotoxicity. A COLIPA analysis. Regul. Toxicol. Pharmacol. 57: 315 -324.

- World Health Organization (WHO). Iodine and inorganic iodides: human health aspects. Concise international chemical assessment document: 72. 2009.

- World Health Organization (WHO). Iodine in dinking water. Background document fo development of WHO guidelines for drinking water quality. 2020.

- Registration dossier of iodine (including PVP-iodine) as an active substance for biocidal products; Assessment report, Iodine (including PVP-iodine) Product types 1, 3, 4, 22, 13 December 2013, Sweden)

Short description of key information:

In vitro gene mutation in bacteria: Equivocal

In vitro cytogenicity studies in mammalian cells: Positive

In vitro gene mutation in mammalian cells: Negative

In vivo test, germ cells: Negative

In vivo tests, somatic cells: Negative

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Iodine is not classified as a germ cell mutagenic substance according to Regulation (EC) No 1272/2008, based on the lack of genotoxic activity of chemically related compound (polyvinylpirrolidone iodine complex) in both germinal and somatic cells in vivo.