A novel dense CO2 supercritical fluid technology for the development of microparticulate delivery systems containing ketoprofen

VarioSol is an innovative, solvent-free technology able to produce microparticles exploiting near-critical CO2 properties as spraying and cooling agent. The aim of the present work was to evaluate the feasibility to produce in a single processing step by VarioSol technology, oral ketoprofen-loaded microparticles with gastro-protective properties. The obtained products were powders composed of regular in shape and small in diameter microparticles, characterized by high drug content (40%) and good flow properties. Microparticles were composed by anionic lipids scarcely soluble at acidic pH, blended with gastro-resistant polymers of the methacrylate type. In vitro drug release results indicated that the drug was rapidly delivered from the microparticulate systems in phosphate buffer at pH 6.8, while in acidic medium, the microparticles were able to retard the drug release process but without reaching complete gastro-resistance. However, the results obtained in this study, although non optimal, are not far from the specifications required for gastro-resistant release products (i.e., no more than 10% drug released after 1 h at pH 1.0) according to EMA guidelines and represent a good starting point for future formulation development.