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The article presents a study which explored the accumulation and distribution of perfluorooctanoic acid (PFOA) in the male and female Wistar rats, following a subchronic and single administration. The study assayed the xenobiotic through gas chromatography-mass spectrometry and gas chromatography. Results indicate the significant difference in PFOA's elimination rate in urine in the two sexes.

0,0′-(l,4-Xylylene) bispilocarpic acid esters are pilocarpine pro-drugs containing two pilocarpic acid monoesters linked with one pro-moiety. Each mole of prodrug forms two pilocarpine moles in the presence of esterases. Corneal uptake and permeability of various bispilocarpic acid diesters were investigated in vitro using isolated albino rabbit corneas. The permeability coefficient of pilocarpine was 2.8 × 10 cm/sec, whereas for bispilocarpic acid diesters, despite their large molecular weights (between 638 and 722), permeability coefficients were 6.5-20.2 × 10 cm/sec. Only pilocarpine, and no intact prodrug, was observed at the endothelial side. Corneal uptake was increased with increasing lipophilicity, but a parabolic relationship between the logarithm of the apparent partition coefficient (1-octanol-pH 7.4 phosphate buffer) (log PC) and the corneal permeability was noticed. Corneal permeability and the rate of enzymatic hydrolysis of the compounds correlated well. The corneal permeability of pilocarpine given as lipophilic bispilocarpic acid diester (log PC ≥3) prodrugs seems to be controlled by the formation of pilocarpine in the corneal epithelium rather than by the absorption of prodrugs into the epithelium or their epithelium-stroma transport rate. [ABSTRACT FROM AUTHOR]

A method is presented for the quantitative determination of perfluorooctanoic acid in plasma and urine. The acid was esterified by an extractive alkylation method using tetrabutylammonium ion as the counter ion and benzyl bromide as the alkylating agent. Quantitation was made by gas chromatography. Typical values for precision obtained in the determination of 5 μg/ml of perfluorooctanoic acid in plasma and urine were 3.3% (S.D. N=6) and 3.0% (S.D. N=6), respectively. The limit of detection was 1 ng (2.4 pmol). [ABSTRACT FROM AUTHOR]

The urinary excretion of perfluorooctanoic acid (PFOA) was studied in male Wistar rats after castration and oestradiol administration as well as in intact females and males. During the first 24 hr females excreted 72±5% (N = 6) of a single intraperitoneal dose of PFOA (50 mg/kg) in urine whereas the intact males excreted only 9±4% (N = 6). After castration followed by oestradiol administration (500 μg/kg every 2nd day for 14 days), the males excreted PFOA in urine in similar amounts as the females (68±14% at 24 hr, N = 10). Oestradiol treatment of non-castrated males produced similar results (61±19% at 24 hr, N = 10). Also castration without oestradiol administration significantly enhanced the renal PFOA excretion, but not as effectively as oestradiol treatment. After 96 hr, the concentration of PFOA in serum of intact males was 17-40 times higher than in the serum of other groups. PFOA was similarly bound by the proteins in the serum of females and males. Phase II metabolism of PFOA was not shown either in males or females. [ABSTRACT FROM AUTHOR]