Diclofenac sodium sustained release hot melt extruded lipid matrices.

Sustained release diclofenac sodium (Df-Na) solid lipid matrices with Compritol® 888 ATO were developed in this study. The drug/lipid powders were processed via cold and hot melt extrusion at various drug loadings. The influence of the processing temperatures, drug loading and the addition of excipients on the obtained dissolution rates was investigated. The physicochemical characterization of the extruded batches showed the existence of crystalline drug in the extrudates with a small amount being solubilized in the lipid matrix. The drug content and uniformity on the tablet surface were also investigated by using energy dispersive X-ray microanalysis. The dissolution rates were found to depend on the actual Df-Na loading and the nature of the added excipients, while the effect of the processing temperatures was negligible. The dissolution mechanism of all extruded formulations followed Peppas-Korsemeyer law, based on the estimated determination coefficients and the dissolution constant rates, indicating drug diffusion from the lipid matrices.

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 12h mainly controlled by diffusion.