Formulation and Characterization of Solid Dispersions of Etoricoxib Using Natural Polymers

The main objective of the present investigation to develop and evaluate solid dispersions of BCS Class II drugs etoricoxib employing various natural polymers, compatible with conventional manufacturing method to enhance solubility of poorly soluble drugs.

In this study, etoricoxib solid dispersion were prepared using xanthan gum, gaur gum and acacia and their combinations by solvent evaporation method. Solid dispersions and pure etoricoxib in the form of powder were characterized in comparison with pure drug and corresponding physical mixtures in the same ratios by Fourier transform infrared spectroscopy, differential scanning calorimetry (DSC), powder X-ray diffractogram, and in vitro drug release.

Solid dispersion (ET11) prepared with 1: 2: 2: 2 drug carrier ratios were showed highest solubility in different solvents. Hence the solid dispersion (ET11) of 1: 2: 2: 2 ratios were selected for characterization. The DSC study indicated that the crystalline nature of etoricoxib was reduced to amorphous. The diffraction pattern of the solid dispersions in each figure indicates that diffraction peaks at 2ɵ values has less intensity than that of pure drugs. This indicated that the crystalline nature of drug sample was converted to amorphous with ET11. Scanning electron microscope photographs of solid dispersion seem to be more porous in nature. From the in vitro drug release profile, it can be seen that formulation ETM11 shows higher dissolution rate i.e. 98.2±1.3% compared with other formulations. It is predicted that, increasing concentration of carrier, increases the drug dissolution rate.

This study has shown that the solid dispersion of etoricoxib using natural carrier can be promising formulation for solubility and dissolution enhancement. Natural polymers used have shown promising results in the modification of drug release from the formulations.