title: Plasma concentrations of S-verapamil after single doses of two different galenic formulations of racemic verapamil.
abstract: The results of enantioselective analysis of verapamil (CAS 52-53-9) in plasma samples obtained at tmax after single dose applications of a 80 mg fast dissoluting (IR) tablet, a controlled release (CR) formulation (240 mg) and an intravenous injection of 5 mg verapamil are reported. The mean fraction of S-verapamil obtained in samples containing the Cmax of racemic verapamil was somewhat smaller after application of the IR-form than observed with the CR formulation. (IR = 15.8 +/- 3.8%; CR = 18.8 +/- 2.0%; p < 0.01), after the intravenous application the mean S-fraction was 32.8 +/- 1.4%. In vitro dissolution tests of the two oral preparations prove that the isomers were released as racemate.
authors.affiliation: Department of Clinical Pharmacology, University Hospital, Frankfurt/Main, Fed. Rep. of Germany.
authors.forename: S
authors.initials: S
authors.lastname: Harder
authors.forename: M
authors.initials: M
authors.lastname: Siewert
authors.forename: P
authors.initials: P
authors.lastname: Thürmann
authors.forename: H
authors.initials: H
authors.lastname: Blume
authors.forename: N
authors.initials: N
authors.lastname: Rietbrock
authors.forename: B
authors.initials: B
authors.lastname: Siewert
mesh_terms: D000284:Administration, Oral; D003692:Delayed-Action Preparations; D006801:Humans; D007275:Injections, Intravenous; D012995:Solubility; D013237:Stereoisomerism; D014700:Verapamil / Q000008:administration & dosage / Q000097:blood* / Q000493:pharmacokinetics
chemical_list: D003692:Delayed-Action Preparations; D014700:Verapamil