Bioavailability of a new sustained-release theophylline capsule in fasted and non-fasted healthy subjects: Single and multiple dosing studies

✍ Scribed by Raelene J. West; Garth Boehm; Mark Dwyer; Desmond B. Williams; Lloyd N. Sansom; Antonio C. Penna

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: English
• Weight: 608 KB
• Volume: 11
• Category: Article
• ISSN: 0142-2782
• DOI: 10.1002/bdd.2510110209

✦ Synopsis

Eighteen healthy, non-smoking, adult volunteers participated in single and multiple dose three-way crossover studies to evaluate a sustained-release, pellet-filled capsule of theophylline, Austyn. The effect of food on the bioavailability of the sustained-release capsule was investigated by administering 300 mg single doses of Austyn, with a high-fat meal and without food and a divided 300 mg dose of the reference product Elixophyllin@ elixir, given after fasting. Plasma theophylline concentrations were measured by fluorescence polarization immunoassay (FPIA) which had been validated against HPLC. The single dose study data showed that there were no significant differences (n = 18, ANOVA, p > 0.05) between the three regimens with respect to AUCo-, values (mg h 1-I), (mean f SD); Elixophyllin@ fasting = 97.1 f 33.7, Austyn with food = 909 * 31-3, Austyn fasting = 91.2 f 33.8. Similarly, multiple dosing with rapid-release Nuelin@ tablets, Austyn capsules, and sustained-release Theo-Due tablets demonstrated that there were no significant differences between regimens with respect to AUC&24h, AUC&,,,,, and AUC,2-24h values calculated from the steady-state concentrations (5th day, 24 h sampling). However, the percentage fluctuation at steady-state over the total blood sampling period was significantly less for treatment with the sustained-release capsule, Austyn, compared with the sustained-release tablet, Theo-Dur@ (Austyn = 36.7 f 13.7 per cent, Theo-Dur@ = 53.1 & 14.1 per cent). The results of the single and multiple dose studies indicate that Austyn capsules demonstrate complete bioavailability, and good controlled release characteristics not influenced by concomitant intake of a high-fat meal and with no evidence of dose dumping.