title: Sustained release properties of the once daily theophylline capsule BY912 as compared with Theo-24 capsules.
abstract: In a multiple dose cross-over experiment in 12 healthy male adults the bioavailability and sustained release characteristics of new once daily BY912 400 mg theophylline capsules (= B, Byk Gulden Research Laboratories, FRG) were studied using Theo-24 capsules (= T, Searle & Co., USA) as reference. Both products were given once daily for a period of 7 days as an 800 mg theophylline dose at 8 am, half an hour after a standardized breakfast. Theophylline concentrations in plasma were measured on days 1, 6, and 7 using high-performance liquid chromatography. Significantly better sustained release characteristics, resulting in longer plateau time (t75%, 11.6 vs 9.2 h on day 6 and 13.1 vs 8.8 h on day 7) and smaller per cent peak-trough fluctuation in the steady state (per cent PTF, 80 vs 103 per cent on day 6 and 66 vs 100 per cent on day 7), were found for B in comparison with T. The extent of absorption on both days, however, was smaller for B compared with T (relative bioavailability 84 per cent and 81 per cent, respectively). In conclusion, the absorption of theophylline from B resulted in a more extended shape of the plateau phase, indicating better sustained release characteristics. The extent of absorption, however, over the dosing intervals was more complete with T.
authors.affiliation: Pharma Bio-Research Int'l B.V., Department of Biopharmaceutics, Assen, The Netherlands.
authors.forename: J H
authors.initials: JH
authors.lastname: Jonkman
authors.forename: V W
authors.initials: VW
authors.lastname: Steinijans
authors.forename: W
authors.initials: W
authors.lastname: Beier
authors.forename: W J
authors.initials: WJ
authors.lastname: van der Boon
authors.forename: G
authors.initials: G
authors.lastname: Crasmeijer
mesh_terms: D000328:Adult; D001682:Biological Availability; D001702:Biopharmaceutics; D002214:Capsules; D002648:Child; D003692:Delayed-Action Preparations; D006801:Humans; D007408:Intestinal Absorption; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D002214:Capsules; D003692:Delayed-Action Preparations; D013806:Theophylline