Sustained release solid lipid matrices processed by hot-melt extrusion (HME)

The aim of this work was to develop sustained release solid lipid matrices of diclofenac sodium (Df-Na) processed by hot melt extrusion (HME) and subsequent compression into tablets. Different extrusion processing approaches such as “cold”, “hot” and pre-mixed formulations were used to develop the Compritol® 888 ATO lipid matrices by altering the extrusion temperatures, drug loading and formulation composition. The extrudates were characterized via a range of techniques such as differential scanning calorimetry (DSC), hot stage microscopy (HSM) and X-ray powder diffraction (XRPD) to identify the drug state within the lipid matrix. Df-Na was found to be either in crystalline or amorphous state depending on the processing conditions. Energy dispersive X-ray (EDX) microanalysis demonstrated excellent drug distribution of Df-Na on the surface of the compressed tablets. The lipid matrices developed by HME provided sustained release of pre-mixed formulations for 12 h mainly controlled by diffusion.