International Journal of Pharma Research 5(2):41-58

Purpose: Current available topical formulations containing non-steroidal anti-inflammatory drugs (NSAIDs) suffer from inadequate efficacy due to drug limited solubility (class II of Biopharmaceutics Classification System) responsible for the incomplete absorption of the administered dose in the application site. Another problem is represented by inadequate formulation, difficult to be applied by a massage on inflamed and injured skin. However often this practice results painful for the patient as the formulation used has been projected without taking account of this problem. The aim of this research was to develop a new topical formulation able to release and make available to absorption the complete administered dose and to make the application easy and pain free using the anti-inflammatory drug ketoprofen (KET) as model drug. Methods: At first KET was intercalated in two lamellar anionic clays hydrotalcites (HTlcs), MgAl-HTlc-NO3 and ZnAl-HTlc-NO3, obtaining the inorganic-organic hybrids MgAl-HTlc-KET and ZnAl-HTlc-KET deeply characterized (XRPD, ICP, TGA, DSC). Then they were formulated in hydrogels submitted to rheological characterization and in vitro release studies using the commercially available formulation for comparison. Results: Hydrogels containing the hybrids showed enhanced flow properties responsible for the enhanced their usability. Particularly, the presence of MgAl-HTlc meets the requirements for KET topical application best of all. Hydrogels showed a sustained release of KET useful to reduce the applications number. Conclusions: KET intercalation into HTlc interlamellar spaces is a good strategy allowing the preparation of topical formulations stable during their shelf life and safe under administration, with enhanced performances in comparison to marketed formulations.