Formulation and development of tinidazole microspheres for colon targeted drug delivery system

The objective of the present study was to formulate and optimize colon targeted tinidazole microspheres. To achieve these objective nine formulations of microspheres were prepared by emulsion solvent evaporation method using Eudragit polymer. A 32 factorial design was employed in formulating the microspheres with concentration of surfactant (A) and stirring speed (B) as independent variables. Percent drug release was considered as dependent variable. The effect of drug-polymer concentration, surfactant concentration, cross-linking agent and stirring speed were evaluated with respect to entrapment efficiency, particle size, surface characteristics, micromeritic properties, DSC study and in vitro drug release studies. The particle size and entrapment efficiency were found to be varied by changing various formulation parameters like surfactant concentration and stirring speed etc. IR study confirmed the drug-polymer compatibility and scanning electron microscopy indicates that the microspheres have the rough and porous surface due to arising as a trace of solvent evaporation during the process. The release profile of tinidazole from Eudragit microspheres was pH dependent. In acidic medium, the release rate was much slower; however, the drug was released quickly at pH 7.4. It is concluded from the present investigation that Eudragit microspheres are promising as a carrier for colon targeted delivery of tinidazole.