N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Basic toxicokinetics

Administrative data

Endpoint:

basic toxicokinetics in vivo

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

1978

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Justification for type of information:

The study was performed as part of the data-set for an Active Substance dossier submitted under Reg. (EC) No 1107/2009.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1978

Report date:

1978

Materials and methods

Objective of study:

absorption

distribution

excretion

metabolism

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study was not performed based on specific guideline.
The excretion and tissue distribution of cyromazine was investigated in two male and one female rats administered a single oral dose of radiolabeled cyromazine. Exhaled volatile metabolites were collected from one rat of each sex. All test animals were housed singly in metal metabolism cages for 72 hours, post dosing, for the collection of urine and faeces.
At termination several tissues (brain, fat, heart, kidneys, liver, lungs, muscle, ovaries, spleen, testes and whole blood) were taken for the measurement of radioactivity present.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

EC Number:

266-257-8

EC Name:

N-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Cas Number:

66215-27-8

Molecular formula:

C6H10N6

IUPAC Name:

N2-cyclopropyl-1,3,5-triazine-2,4,6-triamine

Details on test material:

[U-ring-14C]-N-cyclopropyl-1,3,5-triazine -2,4,6-triamine

Radiolabelling:

yes

Test animals

Species:

rat

Strain:

other: Charles River white rats

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS:
Weight: approximately 170 g each
Housing: One female and two male rates were kept in individual Roth metabolism cages. One female and two male rates were kept in metal cages. Each glass cage was fitted with a dry ice-acetone trap to collect volatiles and a second trap containing 100 ml of 2N NaOH to absorb respiratory CO2.

Administration / exposure

Route of administration:

oral: feed

Vehicle:

carbowaxe

Remarks:

Aqueous Carbowax 400 formulation (1:1 v/v)

Details on exposure:

The rats were dosed orally one time with 0.1 mg of [U-14C triazine]-Cyromazine in 1.0 ml of solution. The dose rate was 0.5 mg/kg (equivalent to 5 ppm in feed).

Duration and frequency of treatment / exposure:

Single oral dose

Doses / concentrations

Dose / conc.:

0.5 mg/kg diet

Remarks:

Dose rate equivalent to 5 ppm feed

No. of animals per sex per dose / concentration:

Two male and one female rats got a single dose

Control animals:

no

Details on study design:

The excretion and tissue distribution of radioactivity was investigated in two male and one female rats administered a single oral dose of 0.5 mg [U-14C triazine]- cyromazine/kg. Exhaled volatile metabolites were collected from one rat of each sex housed individually in glass metabolism cages. All test animals were housed singly in metal metabolism cages for 72 hours, post dosing, for the collection of urine and faeces.
Then, test rats were terminated and a several tissues (including brain, fat, heart, kidneys, liver, lungs, muscle, ovaries, spleen, testes and whole blood) were taken for the measurement of radioactivity present. All samples were analysed for radioactivity by liquid scintillation counting either directly or following sample oxidation. Metabolite profiles in excreta were investigated either by thin layer chromatography or by an Aminex A-5 cation exchange column.

Details on dosing and sampling:

Exhaled volatile metabolites were collected from one rat of each sex housed individually in glass metabolism cages. All test animals were housed singly in metal metabolism cages for 72 hours, post dosing, for the daily collection of urine and faeces.

Results and discussion

Preliminary studies:

No preliminary study was conducted.

Main ADME results

Main ADME results 1

Type:

metabolism

Results:

Unchanged parent compound was dominant in urine (ca.80%), 3 minor metabolites each of which represented less than 5% of the given dose. Faecal metabolite profile similar to urine.

Main ADME results 2

Type:

distribution

Results:

Three days after oral dosing, tissue residues were very low, with <0.007 ppm in the liver and <0.003 ppm in all other tissues.

Main ADME results 3

Type:

excretion

Results:

97% of the administered dose was excreted within 24 hours, predominantly via the kidneys

Main ADME results 4

Type:

absorption

Results:

appeared to be almost complete

Toxicokinetic / pharmacokinetic studies

Details on absorption:

The predominant route of excretion was via the kidneys, with approximately 94% or more of the dose excreted in urine. Faecal elimination accounted for just 4% and 1% of the administered dose in males and the female respectively.

Details on distribution in tissues:

Three days after oral dosing, tissue residues were very low, with <0.007 ppm in the liver and <0.003 ppm in all other tissues.

Details on excretion:

The predominant route of excretion was via the kidneys, with approximately 94% or more of the dose excreted in urine. Faecal elimination accounted for just 4% and 1% of the administered dose in males and the female respectively. Virtually, no radioactivity was recovered from exhaled air.

Metabolite characterisation studies

Metabolites identified:

not specified

Details on metabolites:

Urine contained predominantly the unchanged parent compound, which accounted for approximately 80% of the administered dose and 3 minor metabolites each of which represented less than 5% of the administered dose. Faecal metabolite profiles appeared similar to urine, but because of the low levels of faecal radioactivity, it was not possible to confirm that the metabolites corresponded to those excreted in urine.
Quantitatively determination whether the triazine ring remained intact for urine radioactivity was not possible.

Any other information on results incl. tables

Table 1: Mean recovered radioactivity over 72 hours following a single oral dose of 0.5 mg [U-¹⁴C triazine]-cyromazine/kg in rats

Sample	% of administered radioactivity
	Male (n=2)	Female (n=1)
Urine
0-24 hours	93.8	96.6
24-48 hours	<0.3	0.5
48-72 hours	<0.2	0.3
Sub-total	93.8	97.4
Faeces
0-24 hours	3.8	0.6
24-48 hours	<0.1	0.4
48-72 hours	<0.1	<0.1
Sub-total	3.8	1.0
Cage wash	<0.1	<0.1
Volatile metabolites	<0.1	<0.1
Exhaled carbon dioxide	<0.1	<0.1
Tissues	<0.1	<0.1
Blood	<0.1	<0.1
Intestinal tract	<0.1	<0.1
Total recovery	97.5	98.4

Table 2: Tissue residues (ppm) 72 hours following a single oral dose of 0.5 mg [U-¹⁴C triazine]- cyromazine/kg in rats

Tissue Sample	ppm (µg radiolabeled cyromazine/mg tissue)
	Male (n=2)	Female (n=1)
Blood	<0.002	<0.002
Liver	<0.007	<0.007
Kidneys	<0.002	<0.002
Spleen	<0.002	<0.002
Heart	<0.003	<0.003
Brain	<0.002	<0.002
Ovaries	-	<0.003
Testes	<0.003	-
Muscle	<0.003	<0.003
Fat	<0.002	<0.002

Table 3: Distribution characteristics of [U-¹⁴C triazine]- cyromazine and its metabolites (0-24 hours)

characterization	Percent of Dose
A.TLC	Urine	Feces**	Total
Cyromazine	82.5	-	82.5
Metabolite A*	3.2	-	3.2
Metabolite B*	5.5	-	5.5
Metabolite C*	4.6	-	4.6
B. Aminex A-5
Cyromazine	79.2	<0.1	79.2
Metabolite 1	2.2	<0.1	2.3
Metabolite 2	3.0	0.1	3.1
Metabolite 3	5.3	4.1	9.4

*   It could not be determined if Metabolites A, B, and C, separated on TLC, corresponded to Metabolites 1, 2 and 3, separated on Aminex A-5, because of the low amounts of radioactivity.

** Small amounts of radioactivity in the feces extract did not allow for seperation on TLC plates because of overloading with co- extractants.

Applicant's summary and conclusion

Conclusions:

A single oral dose of 0.5 mg/kg of [U-14C triazine]-cyromazine was almost quantitatively absorbed and rapidly excreted, almost exclusively in the urine. Greater than 97% of the dose was eliminated within 24 hours post dosing while, tissue residues were very low 72 hours after dosing. Cyromazine was poorly metabolised as greater than 80% of the dose was excreted unchanged; there were 3 minor metabolites detected in excreta, each representing less than 5% of the dose.

Executive summary:

Three rats were given a single dose of [U-14C triazine]-Cyromazine at a rate of 0.5 mg/kg (equivalent to 5 ppm in the food). Overall recovery was 97.8%. Most of the radioactive dose was excreted in the urine (95%) with a small amount in the feaces (2.8%). Volatiles and respiratory CO₂ contained less than 0.1% of the dose. Tissues, cage wash, and intestinal tract contained less than 0.1% of the dose. 

Tissue levels were low. Radioactivity equivalent to [U-14C triazine]-Cyromazine in all tissues analysed and blood was less than 0.01 ppm. Rats metabolized the test material slowly to three minor metabolites. These metabolites in urine and feces accounted for 14.8% and unmetabolized test material accounted for 79.2% of the total radioactive dose. The conversion of urine radioactivity to cyanuric acid using nitric acid gave non-reproducable recoveries. Similar results were obtained using standard test material. This methodology cannot quantitatively determine whether the triazine ring remains intact for urine radioactivity. Based on only a small amount of ¹⁴CO₂, the triazine ring is probably intact for all metabolites of the test material.

When dosed orally, the rat was found to rapidly absorb and excrete the test material with minor metabolism. Because of the apparent low lipid solubility of this polar compound, there was little observed tissue retention.