Formulation and in vitro characterization of piroxicam solid lipid microparticles for topical application

Swollen body parts or edema is a condition characterized by increased accumulation of fluid. The aim of this research is to develop a delivery system capable of facilitating improved and controlled topical delivery of piroxicam during high energy activities, including sports. Irvingia fat was extracted from the nut of Irvingia gabonensis var. excelsa (Irvingia wombolu) with petroleum ether (40-60 °C) and analyzed using gas chromatography-mass spectrometry (GC-MS). The extracted fat and its lipid matrices with Phospholipon®90G (P90G) (with and without piroxicam) were characterized by differential scanning calorimetry (DSC) and small angle X-ray diffraction (SAXD). Piroxicam solid lipid microparticles (SLM), based on the extracted lipid, were formulated by hot homogenization and characterized by drug encapsulation efficiency (EE), particle size, yield and dispersion pH. Drug release and diffusion studies were performed for the SLM dispersions using dialysis membrane. The GC-MS indicated presence of C12-C18 fatty acids. The DSC thermograms of the piroxicam-loaded lipid matrices showed melting point of 41 °C, whereas reduced enthalpy and crystallinity were observed in the presence of P90G. The EE of the SLMs were above 98 and particle sizes around 10 µm. Piroxicam SLM dispersions formulated with lipid matrices consisting 3:1 irvingia fat/ P90G had the highest drug diffusion across the membrane. Therefore, solid lipid microparticles based on irvingia fat-P90G structured matrices can be used to improve loading, controlled diffusion, and possibly, overall topical performance of piroxicam.