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The pharmacokinetics and bioavailability of a tracer dose of [3H]‐ mebendazole in man.
Author(s) -
Dawson M,
Braithwaite PA,
Roberts MS,
Watson TR
Publication year - 1985
Publication title -
british journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.216
H-Index - 146
eISSN - 1365-2125
pISSN - 0306-5251
DOI - 10.1111/j.1365-2125.1985.tb02616.x
Subject(s) - mebendazole , bioavailability , pharmacokinetics , half life , pharmacology , oral administration , metabolite , crossover study , volunteer , urine , chemistry , medicine , biology , ecology , alternative medicine , pathology , agronomy , placebo
Five volunteers, whose ages ranged between 37 and 64 years, took part in a crossover study to determine the pharmacokinetics and bioavailability of mebendazole in man following intravenous and oral administration of a tracer dose of [3H]‐mebendazole. Following intravenous administration, the average distribution half‐life, elimination half‐life and rate of clearance were 0.20 h, 1.12 h, and 1.063 min respectively. After oral administration of the solution, the average elimination half‐life was 0.93 h, the apparent rate of clearance was 0.846 l/min, the average time to peak plasma concentration was 0.42 h, and the bioavailability of mebendazole was 22%. Comparison of metabolite area under the plasma concentration vs time data from each route of administration indicates that absorption of mebendazole from the gastrointestinal tract at this dose level is almost complete. The low bioavailability observed following oral administration at this dose level is postulated to be due to high first pass elimination. Approximately half of the administered dose of radioactivity following intravenous and oral administration was detected in the urine, and the major unconjugated metabolite of mebendazole was found to be 2‐amino‐5(6) [alpha‐ hydroxybenzyl]benzimidazole (IV), not 2‐amino‐5(6)benzoylbenzimidazole (II), as previously reported.