Bioequivalence Study Between Two Extended-Release Formulations of Theophylline Using Saliva

Abstract

Objective:

To assess the bioequivalence between two extended-release formulations of theophylline using saliva as the biologic fluid.

Design:

Randomized two-way crossover design.

Participants:

Eight healthy, nonsmoking volunteers (7 women, 1 man) between 23 and 41 years of age took a single dose (250 mg) of two extended-release formulations of theophylline (form A, tablet; form B, capsule).

Results:

Significant differences were found at 2, 4, 6, and 8 hours (p < 0.001), with the in vitro dissolution test between both formulations. ANOVA for AUC, maximum concentration (C_max), average concentration, and %C_max – 100 showed significant differences between both formulations in the in vivo trial.

Conclusions:

The tablet and capsule formulations of extended-release theophylline are bioinequivalent when saliva is used as the biologic fluid for performing these studies.