FORMULATION, CHARACTERIZATION AND IN-VITRO / EX-VIVO EVALUATION OF TROLAMINE SALICYLATE – LOADED TRANSFERSOMES AS TRANSDERMAL DRUG DELIVERY CARRIERS

The percutaneous delivery of salicylates to muscle and joints via the application of trolamine salicylate including transfersomes is the goal of this study and is beneficial for the treatment of inflammatory muscle, tendon and joint diseases. In this study, Trolamine salicylate permeability parameters through rat skin were evaluated with different trasfersome formulations in comparison with controls with Franz diffusion cells. Transfersomes were prepared with Solvent evaporation technique. Full factorial design was applied for the experimental design and data analysis. Ethanol / lipid ratio, percentage of sodium cholate, and homogenizer rate were considered as independent variables. On the other hand, transfersome size, drug loading, stability, drug release and skin permeability parameters were regarded as responses. The results showed that the main barrier for Trolamine salicylate permeability was the horny layer and partitioning from aqueous donor phase into the skin was rate limiting step for drug flux. Maximum flux and diffusion coefficient enhancement obtained by transfersomes no. 8 and 7 were 5.5 and 2.2 – folds, respectively. Regression analysis suggested significantly and indirect correlation between percentage of ethanol and sodium cholate with drug flux. Ethanol increased drug solubility in vehicle and so decreased drug partitioning into the skin. Sodium cholate decreased drug release and skin penetration by stabilization of lamellar membrane. Therefore, partitioning from vehicle into skin is a rate limiting step for Trolamine salicylate permeability through rat skin which was improved by transfersomes.