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The aim of this investigation was to assess the pharmacokinetics of naproxen in 10 human subjects after an oral dose of 500 mg using a direct HPLC analysis of the acyl glucuronide conjugates of naproxen and its metabolite O-desmethylnaproxen. The mean t1/2 of naproxen in 9 subjects was 24.7 +/- 6.4 h (range 16 to 36 h). The t1/2 of 7.4 as found in subject… (More)
The turtle Pseudemys scripta elegans acetylates and O-dealkylates sulphamethomidine. The yield of acetylation (3.1%) is about 0.7 times greater than the yield of O-dealkylation (4.3%).
The turtle Pseudemys scripta elegans is able to hydroxylate and acetylate Sulphamethoxazole in a way that is comparable to man, i.e. the rate and yield of hydroxylation equals that of the acetylation. The hydroxy metabolites 5-hydroxy- and N4-acetyl-5-hydroxysulphamethoxazole are not glucuronidated. N4-acetylsulphamethoxazole is neither deacetylated nor… (More)
The turtle Pseudemys scripta elegans hydroxylates nalidixic acid into 7-hydroxynalidixic acid; this latter metabolite is oxidised into 7-carboxynalidixic acid. The elimination half-life of nalidixic acid in the turtle is 30 h. No glucuronides of nalidixic- and 7-hydroxynalidixic acid are formed, as they are in man.
Sulfamethoxazole and N4-acetylsulfamethoxazole are excreted by fresh water turtles Pseudemys scripta elegans in a biphasic mode, characterized half-lives of 5 and 100 min. Acetylation and deacetylation reactions cannot be detected below a dose of 50 mg/kg. The mass balance of the dose administered is incomplete, only 30 per cent of the dose can be recovered… (More)
After an oral dose of 350 mg of sulphadimethoxine, the turtle Pseudemys scripta elegans O-dealkylates sulphadimethoxine at the 2- and 6-position at 38% and 19% respectively, the 2-position being favoured. Acetylation of sulphadimethoxine and its hydroxy metabolites occurs for 57.4%.
Sulphamonomethoxine is O-demethylated at the 6 position and oxidised at the 2 position of the pyrimidine substituent by Pseudemys scripta elegans. No N4-acetylation takes place. The yield of the oxidation reaction is twice that of the O-demethylation reaction.