Dicalcium pyrophosphate

Skin irritation / corrosion

Administrative data

Endpoint:

skin corrosion: in vitro / ex vivo

Remarks:

in vitro

Type of information:

experimental study

Adequacy of study:

key study

Study period:

27 - 29 July 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2011

Report date:

2011

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

OECD Guideline 431 (In Vitro Skin Corrosion: Human Skin Model Test)

Version / remarks:

2004

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test material

Test material information

Constituent 1

Reference substance name:

Dicalcium pyrophosphate

EC Number:

232-221-5

EC Name:

Dicalcium pyrophosphate

Cas Number:

7790-76-3

Molecular formula:

Ca2O7P2

IUPAC Name:

dicalcium pyrophosphate

Test material form:

solid: particulate/powder

Remarks:

migrated information: powder

In vitro test system

Test system:

human skin model

Source species:

human

Cell type:

non-transformed keratinocytes

Cell source:

other: not specified

Source strain:

not specified

Vehicle:

unchanged (no vehicle)

Details on test system:

RECONSTRUCTED HUMAN EPIDERMIS (RHE) TISSUE
- Model used: EPISKIN™ in vitro reconstructed human epidermis model
- Tissue batch number(s): not specified
- Production date: not specified
- Shipping date: not specified
- Delivery date: 27 July 2010
- Date of initiation of testing: the study was performed between 27 and 29 July 2010

TEMPERATURE USED FOR TEST SYSTEM
- Temperature used during treatment / exposure: room temperature

REMOVAL OF TEST MATERIAL AND CONTROLS
Rinsing was achieved by filling and emptying each tissue insert for approximately 40 seconds using a constant soft stream of PBS with Ca++ an Mg++ to gently remove any residual test material. Each rinsed tissue was placed into the third column of the 12-well plate until all tissues were rinsed.

MTT DYE USED TO MEASURE TISSUE VIABILITY AFTER TREATMENT / EXPOSURE
- MTT concentration: 0.3 mg/mL
- Incubation time: 3 hours ± 5 minutes
- Spectrophotometer: Anthos 2001 microplate reader
- Wavelength: 540 nm
- Filter: without reference filter

FUNCTIONAL MODEL CONDITIONS WITH REFERENCE TO HISTORICAL DATA
- Viability:
- Barrier function:
- Morphology:
- Contamination:
- Reproducibility:

NUMBER OF REPLICATE TISSUES: 2

NUMBER OF INDEPENDENT TEST SEQUENCES / EXPERIMENTS TO DERIVE FINAL PREDICTION:

PREDICTION MODEL / DECISION CRITERIA (choose relevant statement)
- The test substance is considered to be corrosive to skin if the viability after 3 minutes exposure is less than 35%, or if the viability after 3 minutes exposure is greater than or equal to 35% and the viability after 1 hour exposure is less than 35%. The test substance is considered to be corrosive to skin if the viability after 60 minutes exposure is greater than or equal to 35% and the viability after 240 minutes exposure is less than 35%.
- The test substance is considered to be non-corrosive to skin if viability after 240 minutes exposure is greater than or equal to 35%.

Control samples:

yes, concurrent negative control

yes, concurrent positive control

Amount/concentration applied:

TEST MATERIAL
- Amount(s) applied: 20 mg
- Other: 100 µl of 0.9% w/v sodium chloride solution was added for wetting of the test item.

VEHICLE
no vehicle used

NEGATIVE CONTROL
- Amount(s) applied: 50 µL
- Concentration: 0.9% (w/v) sodium chloride solution

POSITIVE CONTROL
- Amount(s) applied: 50 µL glacial acetic acid

Duration of treatment / exposure:

Test material: 3, 60 and 240 min
Negative and positive controls: 240 min

Duration of post-treatment incubation (if applicable):

not applicable

Number of replicates:

duplicates

Results and discussion

In vitro

Results

Results 1

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

3 min

Value:

117.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 2

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

60 min

Value:

135.4

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Results 3

Irritation / corrosion parameter:

% tissue viability

Run / experiment:

240 min

Value:

105.6

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

no indication of irritation

Other effects / acceptance of results:

- OTHER EFFECTS:
- Visible damage on test system: not specified
- Direct-MTT reduction: no
- Colour interference with MTT: no

ACCEPTANCE OF RESULTS:
- Acceptance criteria met for negative control: not specified
- Acceptance criteria met for positive control: yes
- Acceptance criteria met for variability between replicate measurements: not specified

Mean OD540 values and viabilities for the negative control, positive control and test material are given in Table 1.
The qualitative evaluation of tissue viability is given in Table 2. Following the 3, 60 and 240 min exposure periods the test material treated tissues appeard blue which was considered to be indicative of viable tissue.

Any other information on results incl. tables

Table1 :Mean OD₅₄₀Values and Viabilities for the Negative Control Item, Positive Control Item and Test Item

 

Item	Exposure period	Mean OD540of duplicate tissues	Relative mean viability (%)
Negative control**	240 minutes	0.161	100*
Positive control**	240 minutes	0.005	3.1
Test substance	240 minutes	0.170	105.6
	60 minutes	0.218	135.4
	3 minutes	0.189	117.4

* = The mean viability of the negative control tissues is set at 100%

** = Control group shared with Harlan Laboratories Ltd Project numbers 2920/0150, 2920/0151, 2920/0153, 2920/0154 and 2920/0155

Table2 : Qualitative Evaluation of Tissue Viability (MTT uptake visual evaluation)

 

Item	Exposure period	Mean OD540of duplicate tissues	Relative mean viability (%)
Negative control*	240 minutes	-	-
Positive control*	240 minutes	++	++
Test substance	240 minutes	-	-
	60 minutes	-	-
	3 minutes	-	-

- = Blue tissue (viable)

+ = Blue/white tissue (semi-viable)

++ = Tissue completely white (dead)

* = Control group shared with Harlan Laboratories Ltd Project numbers 2920/0150, 2920/0151, 2920/0153, 2920/0154 and 2920/0155

Quality Criteria

The relative mean tissue viability for the positive control treated tissues was 3.1% relative to the negative control treated tissues following the 240-Minute exposure period. The positive control acceptance criterion was therefore satisfied.

Applicant's summary and conclusion

Interpretation of results:

GHS criteria not met

Conclusions:

The relative mean cell viability of the test material treated tissues was 117.4, 135.4 and 105.5% after 3, 60 and 240 min exposure, respectively. Under the conditions of this study, the test material is thus considered to be not corrosive in vitro. Therefore, the test material does not meet the criteria for classification for Skin corrosion Category 1 according to Regulation (EC) No 1272/2008 (CLP) or the Globally Harmonized System (GHS).

CLP: not classified
GHS: not classified