Pesticide residues in food — 2006: Toxicological ... - ipcs inchem

242
In male and female monkeys given a single oral dose of [U- 14 C triazine]cyromazine at 0.05 or
0.5 mg/kg bw, cyromazine accounted for more than 94% of urinary radioactivity, with the remainder
attributable mainly to melamine (Staley, 1986).
Table 14. Relative proportions of cyromazine and melamine in samples of urine collected from
monkeys over 24 h after a single oral dose of mg [U- 14 C triazine]cyromazine at 0.05 or 0.5/kg bw
Sex Dose (mg/kg bw) Cyromazine (%) Melamine (%)
Male 0.05 95.35 3.26
Female 0.05 94.10 5.90
Male 0.5 94.84 3.92
Female 0.5 94.90 3.37
From Staley (1986)
A second study was performed with one male and one female of the same strain of monkey
and the same doses given by capsule as in Staley (1986). Each monkey was housed in a metabolism
cage to which it had been first acclimatized. Urine and faeces were collected for 24 h before dosing
and each day after dosing for 2 days. Radioactivity in urine and in combusted samples of faeces
was measured by LSC. Aliquots of urine collected over the first 24 h after dosing were analysed by
TLC against cyromazine and melamine reference standards. The study was not performed according
to GLP, but it was an investigative study designed to complement the regulatory submission on
metabolism. The study was regarded as additional information for the evaluation.
In all day-1 urine samples, approximately 95% or more of the radioactivity present was
characterized as cyromazine and the remainder as melamine (Table 15). There was considered to be
no difference in metabolism between the doses or between the sexes.
In male and female monkeys given a single oral dose of [U- 14 C triazine]cyromazine at 0.05 or
0.5 mg/kg bw, cyromazine accounted for approximately 95% or more of urinary radioactivity with
the remainder mainly attributable to melamine (Staley & Simoneaux, 1986).
Table 15. Relative proportions of cyromazine and melamine in samples of urine collected from
monkeys over 24 h after a single oral dose of [U- 14 C triazine]cyromazine at 0.05 or 0.5 mg/kg bw
Sex Dose (mg/kg bw) Cyromazine (%) Melamine (%)
Male 0.05 100.00 0.00
Female 0.05 96.08 3.92
Male 0.5 94.99 3.73
Female 0.5 97.01 3.00
From Staley & Simoneaux (1986)
Goats
Lactating goats received [U- 14 C triazine]cyromazine at a dose equivalent to a dietary
concentration of 4.6 and 48.4 ppm for 10 days.
Cyromazine accounted for 43.7%, 35.9%, 0.2% and 32.5% of the extractable radioactivity
in the urine, faeces, liver and milk, respectively at the lowest dose and 78.8%, 58.7%, 1.9% and
41.0% at the highest dose, respectively. Melamine concentrations in the urine, faeces, liver and milk
were 11.9%, 14.3%, 1.7% and 9.2% at the lowest dose and 7.8%, 10.4%, 5.6% and 4.5% at the
highest dose, respectively. 1-Methylcyromazine accounted for 44.4%, 17.4%, 92.7% and 1.0% of
the extractable radioactivity at the lowest dose and 13.4%, 1.8%, 71.7% and 0.2% at the highest
dose in urine, faeces, liver and milk, respectively (Simoneaux & Marco, 1984). This study had been
evaluated by the 1990 JMPR and was not reviewed by the present Meeting.
CYROMAZINE X-X JMPR 2006