Absorption and distribution of orally administered siloxanes in rat organs.
Polimery 2001, No 7-8, 546
SummaryMale "Wistar" rats, each ca. 200 g, were fed, each ca. 50 g/day, with (i) a 95% of granulated LSM + 5%) of OM-300 polydimethylsiloxane (PDMS) oil (viscosity about 300 cSt) fodder and (ii) a (95:5 w/w) LSM - polydimethylcyclosiloxane (cPDMS) oil (i.e., a (1:1) hexamethyltricyclosiloxane (D3) - octamethyltetracyclosiloxane (D4) mixture) fodder. Absorption from the alimentary tract and distribution of siloxanes in blood, brain, kidneys, liver and spleen was studied over a 24-hour period in the animals given the first lot of fodder and killed by one in l, 5 and 24 h. Accumulation and toxic effects of siloxanes were studied in blood, brain, kidneys, liver and spleen in the animals killed after 12 days (Table 1). Silicones were extracted with CCl4 and determined by recording lH NMR spectra on a Tesla Brno BS-587 A 80-MHz spectrometer. In groups (i) and (ii), the mean siloxane concentrations in the blood after 12 days were 26±14 and 70±97 µg/mL, resp. In the specific organs, siloxanes differed only insignificantly between group (i) and (ii), except for brain where group (i) exceeded group (ii). In two rats, one given (a) LSM + 1 g OM-300 and the other given (b) LSM + 1 g cPDMS, the 24 h urine and feces contained (a) 300 µg and 800 mg silicones, resp., and (b) 10-30 µg and 400 mg, resp. PDMS are preferentially absorbed by the brain and kidneys; cPDMS remain in the circulatory system and partly in kidneys. The internal organs showed no pathological changes attributable to siloxanes.