Appendices 1-18 to: Report on the Health Effects of Selected Pesticide Coformulants

137     Toxicokinetics

137.1     Absorption, distribution, metabolism and elimination
137.2     Mode of action

137.1     Absorption, distribution, metabolism and elimination

No data were available on the uptake of HMP. However toxicological data indicate that the substance is absorbed both after inhalation and after oral intake.

HMP was identified in serum as the major metabolite following a single intraperitoneal administration of 450 mg/kg of methyl isobutyl ketone (MiBK) to guinea pigs. MiBK and HMP had serum half-lives of 78 minutes and 66 minutes, and clearance times of 6 hours and 16 hours, respectively. The authors stated that a hydroxylation product like HMP would commonly be eliminated in urine as O-sulfate or O-glucuronide or may enter the intermediary metabolism to be eliminated as CO2 or to be incorporated into tissues. (DiVincenzo et al. 1976).

The metabolic fate of 4-hydroxymethyl-4-methyl-2-pentanone (HMP) was investigated in Charles River CD-1 mice by measuring blood and brain concentrations at 15, 30, 60 and 90 minutes following intraperitoneal injection. Administration of 290 mg HMP/kg b.w. resulted in levels from approximately 430, 300, 160 and 50 mg/ml blood and 430, 300, 150 and 60 mg/g brain at 15, 30, 60 and 90 minutes after dosing. No metabolites were detected. (Granvil et al. 1994).

 

137.2     Mode of action

No information was found.