Comparative bioavailability study of theophylline in suppositories relative to oral capsules and prolonged release tablets

ABSTRACT

A comparative bioavailability testing was carried out on theophylline [TH] suppositories [200 mg] in a hard fatty base and aminophylline [AM] suppositories [250 mg] in a polyethylene glycol [PEG] blend. The study was performed on 6 male healthy volunteers in a cross-over fashion. Theophylline saliva concentration data were compared with those obtained for aminophylline oral capsules [250 mg] and prolonged release [PR] [200 mg] theophylline tablets [Quibron SR]. The results showed that bioavailability of TH from hard fat and PEG suppositories, and from PR tablets were 71%, 76%, and 57%, relative to the oral capsules AUC 0-12, respectively. Other pharmacokinetic parameters, such as T max and MRT were highest for PR tablets [4.16 and 19.07 h, respectively] and lowest for AM capsules [1.08 and 9.49 h, respectively]. The two suppository formulations had intermediate values