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Sustained release properties of the once daily theophylline capsule BY912 as compared with Theo–24® capsules
Author(s) -
Jonkman J. H. G.,
Steinijans V. W.,
Beier W.,
Van Der Boon W. J. V.,
Crasmeijer G.
Publication year - 1989
Publication title -
biopharmaceutics and drug disposition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.419
H-Index - 58
eISSN - 1099-081X
pISSN - 0142-2782
DOI - 10.1002/bdd.2510100210
Subject(s) - theophylline , capsule , pharmacology , bronchodilator , chemistry , medicine , biology , asthma , botany
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 highperformance liquid chromatography. Significantly better sustained release characteristics, resulting in longer plateau time ( t 75% , 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.