development of topical hydrogels of terbinafine hydrochloride and evaluation of their antifungal activity the purpose of this study was to prepare hydrogels and microemulsion mebased gel formulations containing 1 terbinafine hydrochloride terhcl and to evaluate the use of these formulations for the antifungal treatment of fungal infections three different hydrogel formulations were prepared using chitosan carbopol 974 and natrosol 250 polymers a pseudoternary phase diagram was constructed and starting from me formulation a me gel form containing 1 carbopol 974 was prepared we also examined the characteristic properties of the prepared hyrogels the physical stability of hydrogels and the me based gels were evaluated after storage at different temperatures for a period of 3 months the release of terhcl from the gels and the commercial product lamisil was carried out by using a standard dialysis membrane in phosphate buffer ph 52 at 32c the results of the in vitro release study showed that the natrosol gel released the highest amount of drug followed by carbopol gel chitosan gel commercial product and the microoemulsionbased gel in that order in vitro examination of antifungal activity revealed that all the prepared and commercial products were effective against candida parapsilosis penicillium aspergillus niger and microsporum these results indicate that the natrosolbased hydrogel is a good candidate for the topical delivery of terhcl