Nitin Singh, Suman Jain 1
Abstract : The current study was aimed at formulating and evaluating hydrogel containing microemulsion of Bifonazole and an attempt was made to investigate the suitability of Tamarind gum as a gelling agent.
The microemulsion of bifonazole is assumed to increase the cutaneous absorption of the medicament when compared to conventional vehicles (emulsion, pure oil, aqueous solutions). Thus it is assumed that topical microemulsion of bifonazole with increased bioavailability by controlled release of drugs with prolonged residence time will be much favourable for the treatment of fungal infections and symptomatic relief.
The Tamarind gum as a gel matrix was used to construct the microemulsion based hydrogel for improving the viscosity of microemulsion for topical administration. A ternary phase diagram was constructed using oleic acid as the oil phase, tween 80 as surfactant and propylene glycol as co-surfactant to obtain microemulsion region. The o/w type microemulsion of bifonazole was Organization Logo Photograph prepared by water titration method. The ratio of surfactant and co-surfactant was optimized by constructing pseudoternary phase diagram.
Results and Discussions
The optimized microemulsion based hydrogels showed pH in the range of 6.42 to 6.95, drugcontent 99.43%, spreadibility in the range of 4.6 to 7.4gm.cm/sec. The viscosity study indicated the pseudo plastic behaviour of all microemulsion based gel formulations. Amongst the studied microemulsion gels, Tamarind gum containing gels exhibited fast and complete drug releas 90.43% at the end of 24h. The mechanism of drug release from microemulsion-based hydrogel was observed to follow zero-order kinetics. Formulation F5 containing Tamarind gum showed a wide zone of inhibition and found to be stable for one month.
These results indicate that the studied micro emulsion-based hydrogel has the potential for sustained action of drug release and may be used as a vehicle for topical delivery for bifonazole. The main advantage of microemulsions over gels is that they are used to solubilize drugs and to improve topical drug availability.