Design and study of poloxamer-based microemulsion gels with naproxen

In this study novel microemulsion-based gels with poloxamer 182 as a surfactant were designed and investigated as potential carriers for topical dosage forms with naproxen, non-steroidal anti-inflammatory drug. Based on the analysis of the pseudoternary phase diagrams obtained with the use of different components, oleic acid was selected as an oil phase and ethanol, isopropanol and Transcutol (R) were used as cosurfactants. As a polar phase pure water and poloxamer 407 solutions were tested. The extent of monophasic areas was similar in both cases, however, the poloxamer solutions were excluded from further experiments because of the lack of gelling properties in the studied systems. As a thickening agent Carbopol (R) EZ-3 was selected. In three microemulsion systems with different cosurfactans electrical conductivity was analysed as a function of polar phase content in order to find the transition points corresponding to microstructural changes leading to different microemulsion types. In the next step, three bicontinuous systems were transformed into semisolid polymer gels and subjected to rheological and texture profile analyses in order to assess mechanical parameters important in terms of topical drug delivery.