Thermoanalytical method for predicting the hydration effect permanency of dermal semisolid preparations

Our aim was to develop potential dermal drug delivery systems (DDSs) with a good and lasting mois- turizing effect. Lyotropic liquid crystals (LLCs), gel- emulsions and hydrogels were investigated by means of thermogravimetry, which can give information about the structure of these preparations, and we could study the water binding mechanisms indirectly in them. We found that the preparations with a complex structure and strong water bonds hydrate the skin well and lastingly by in vivo tests. Since the thermoanalytical results correlate with the in vivo test results, this method could be suited for pre- dicting the moisturizing effect of the vehicles and provide the possibility to select the potential semisolid DDSs for in vivo tests cost and time effectively.