title: Assessment of bioavailability of experimental single-unit sustained release tablets of verapamil hydrochloride using the stable isotope technique.
abstract: A stable isotope technique has been used to assess the bioavailability of sustained release verapamil products. The test formulations were tablets with a core containing 90 mg of verapamil hydrochloride coated with ethylcellulose film, the permeability of which was controlled using different amounts of hydroxypropyl methylcellulose. A product containing ethylcellulose 75% hydroxypropyl methylcellulose 25% w/w gave a single-unit sustained release tablet of verapamil hydrochloride that allowed a dose interval of 24 h. There was no loss in bioavailability, even though verapamil had extensive first-pass metabolism.
authors.forename: M
authors.initials: M
authors.lastname: Marvola
authors.forename: A
authors.initials: A
authors.lastname: Kannikoski
authors.forename: J
authors.initials: J
authors.lastname: Taskinen
authors.forename: P
authors.initials: P
authors.lastname: Ottoila
mesh_terms: D000042:Absorption; D000328:Adult; D001682:Biological Availability; D003692:Delayed-Action Preparations; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006207:Half-Life; D006801:Humans; D007700:Kinetics; D008297:Male; D012995:Solubility; D013608:Tablets, Enteric-Coated; D014700:Verapamil / Q000008:administration & dosage* / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D013608:Tablets, Enteric-Coated; C016904:norverapamil; D014700:Verapamil