LORATADINE-LOADED MICROEMULSIONS FOR TOPICAL APPLICATION. FORMULATION, PHYSICOCHEMICAL CHARACTERIZATION AND IN VITRO DRUG RELEASE EVALUATION

The aim of this study was to develop and evaluate several microemulsion (ME) formulations as topical delivery systems for loratadine (LRT), a second-generation H1 antihistaminic drug, used for allergic skin manifestations treatment. The solubility of LRT in different oils, non-ionic surfactants and cosurfactants was determined to select the ME components. Establishment of pseudoternary phase diagrams, using a relatively new method (Phase Diagram by Micro Plate Dilution) for several systems, including the Captex 355/Cremophor Rh 40-Capryol 90/water system, was used to select the studied ME and gelME. The selected LRT-loaded ME were characterized for physicochemical properties and in vitro drug release through synthetic membrane. The results showed great impact of the ME components and their proportions on the mentioned characteristics. Three of the assessed ME, presenting permeation profiles best fitted with Korsmeyer-Peppas model, were suggested to be firstly evaluated for the in vitro drug release through a biological membrane model.