Preparation of Sustained Release Phenobarbitone Microspheres Using Natural and Synthetic Polymers

Abstract

Rounded and uniform shape phenobarbitone microspheres were successfully prepared using Eudragit RL. The yield percent, the actual drug content and the incorporation efficiencies of the prepared microspheres increased with increasing the drug: polymer ratio. The particle size analysis data showed an increase in the mean microspheres diameter from 235.54 to 292.58 μm with increasing the amount of polymer from 1:1 to 1:4 ratios. The dissolution studies revealed that the phenobarbitone release was greatly extended and delayed as the drug-polymer ratio was decreased due to the increase in the diffusion pathway through the pores of the polymer. Sustained release casein-chitosan microspheres containing phenobarbitone were also prepared using the coacervation technique in completely aqueous conditions. The entrapment efficiencies (83.20-90.60%), particle size (620.5 - 675 μm), flow properties; compressibility and in vitro dissolution of the microspheres were variable depending on the preparation conditions. Casein and chitosan concentrations were found to be the main parameters that affect the properties and the performance of the prepared microspheres. Eudragit RL microspheres showed more prolonged and slower drug release than casein-chitosan microspheres, however, the release rates were prolonged from both types of microspheres.