Tolnaftate (O-2-Naphthyl m, N-dimethylthiocarbanilate) is a topically used antifungal agent, most commonly employed in the treatment of Tinea Pedis at 1% (w/w) concentration. In the global market tolnaftate is available in form of solutions, aerosols, powders and creams (in form of suspension), while no semisolid dosage forms with dissolved tolnaftate are available. Thus in the present study efforts were made to formulate stable semisolid preparations containing 1% of tolnaftate. It was attempted to formulate preparations where tolnaftate is dissolved. Tolnaftate is highly lipophilic (LogP 5.6), therefore it was necessary to evaluate its solubility. Solubility was evaluated in organic solvents, aqueous solutions of surface active substances, polyethylene glycols and oils. On the basis of solubility studies oleogels, hydrophilic non-aqueous gels and macrogol ointments were prepared. These preparations were compared with creams (O/W), where tolnaftate was suspended in the vehicle. Formulation characteristics, such as spreadability, rheological and mechanical properties, are the most important factors in the development of semisolid formulations. These tests were carried out with a purpose to select formulations for stability evaluation. It was impossible to achieve 1% (w/w) tolnaftate concentration in prepared oleogels and organogels. A solution was successfully obtained in macrogol ointments, however ointment chosen for stability evaluation was found to be instable during 2 months storage, probably due to interaction between tolnaftate and polyethylene glycols. Cream (o/w) formulated with triglycerides (Precirol®) and 70% of water was found to have suitable organoleptic properties, stable semisolid consistency and did not undergo any significant changes during 2 month storage in 4oC. The cream should be further investigated in long term stability studies.

Raktažodžiai: Tolnaftate, semisolids, developement, analysis, stability