Gastro-retentive dosage form for improving bioavailability of Cefpodoxime proxetil in rats.

Cefpodoxime proxetil (CP) is a prodrug with poor oral bioavailability because of its metabolism to Cefpodoxime acid (CA) in luminal contents and intestinal epithelial cells. In the present investigation, regional variability in different segments of the gastrointestinal tract vis-à-vis solubility and metabolism were investigated, and the results indicated potential for a gastro retentive (GR) dosage form. Suitability of a GR dosage from for CP and finally in vivo efficacy were investigated. Thereafter, an effervescent floating GR dosage form was developed for CP and evaluated in rats. The GR dosage form improved the oral bioavailability of CP significantly by about 75%, hence providing a proof-of-concept. The Tmax value increased to 1.43+/-0.24 h from 0.91+/-0.23 h of pure drug, while Cmax values of 4735+/-802 ng/ml and 3094+/-567 ng/ml were obtained for the GR dosage form and pure drug respectively.