title: Pharmacokinetics and bioavailability of drotaverine in humans.
abstract: The pharmacokinetics and bioavailability of drotaverine was studied in 10 healthy volunteers after administration of single 80 mg oral and intravenous doses of the HCl salt of the drug, in a crossover fashion. Plasma and urine samples were analyzed for the unchanged drug by HPLC. The pharmacokinetic parameters, such as elimination half-life, plasma clearance, renal clearance and apparent volume of distribution, were not influenced by the route of drug administration. The drug was mainly eliminated by non-renal routes since renal clearance accounted for only 0.31 +/- 0.13% of the total plasma clearance. The absolute bioavailability was variable and ranged from 24.5-91% with a mean of 58.2 +/- 18.2% (mean +/- SD). It is suggested that the high variation in the bioavailability of drotaverine HCl after oral administration may result in significant interindividual differences in therapeutic response.
authors.affiliation: Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria.
authors.forename: O O
authors.initials: OO
authors.lastname: Bolaji
authors.forename: C O
authors.initials: CO
authors.lastname: Onyeji
authors.forename: A O
authors.initials: AO
authors.lastname: Ogundaini
authors.forename: T A
authors.initials: TA
authors.lastname: Olugbade
authors.forename: F A
authors.initials: FA
authors.lastname: Ogunbona
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D006801:Humans; D007275:Injections, Intravenous; D010208:Papaverine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D010276:Parasympatholytics / Q000493:pharmacokinetics*
chemical_list: D010276:Parasympatholytics; C005317:drotaverin; D010208:Papaverine