Acta Pharm. 56 (2006) 285-298[ Full paper in PDF ]
The objective of the present investigation was to study the influence of polyethylene glycol 4000 (PEG) and polyvinylpyrrolidone K30 (PVP) on in vitro dissolution of etoricoxib from solid dispersions. Preliminary studies were carried out using a physical mixture of the drug and carriers. Solid dispersions were prepared using the solvent evaporation method.
A 32 factorial design was adopted in the solvent evaporation method using the concentration of PEG and PVP as independent variables. Full and reduced models were evolved for dependant variables, such as the percentage of drug release in 10 min (Q10), percentage of drug release in 30 min (Q30), percentage of drug release in 45 min (Q45) and percent dissolution efficiency (DE). The reduced models were validated using two check points. Q10 > 65%, Q30 > 75%, Q45 > 85% and DE > 80% were used as constraints for the selection of an optimized batch. Contour plots are presented for the selected dependant variables. PEG was found to be more effective in increasing the drug dissolution compared to PVP. Wettability study was carried out for pure drug and optimized batch. FT-IR spectroscopy, microscopic study, differential scanning calorimetry and X-ray diffraction study were carried out in order to characterize the drug in solid dispersions. Improved dissolution was attributed to decreased crystallinity of the drug, improved wetting and solubilizing effects of carriers such as PEG and PVP from the solid dispersion of etoricoxib. In conclusion, dissolution of etoricoxib can be modulated using appropriate levels of hydrophilic carriers.
Keywords: etoricoxib, solid dispersions, dissolution, polyethylene glycol, polyvinylpyrrolidone, factorial design