Study on Effect of Excipients in Enhancing the Solubility of Nateglinide by Solid Dispersions

Nateglinide is a novel anti diabetic drug that lowers blood glucose levels by stimulating insulin secretion from the pancreas. This action is dependent upon functioning beta-cells in the pancreatic islets. One of the major problems with this drug is its low solubility in biological fluids, which results into poor bioavailability after oral administration. Therefore, solid dispersions (SDs) of nateglinide were prepared using lactose, mannitol and urea to increase its aqueous solubility. Nateglinide SDS was prepared in 1:1, 1:2, and 1:3 ratios of the drug to polymer (by weight). In vitro release profiles of all SDs (F-1 to F-9) were comparatively evaluated and also studied against pure Nateglinide. Faster dissolution was exhibited by solid dispersion containing 1:3 ratio of drug: mannitol. The increase in dissolution rate of the drug may be due to increase in wettability, hydrophilic nature of the carrier and due to reduction in drug crystallinity. The prepared solid dispersion was subjected for % practical yield, drug content and infrared (IR) spectroscopic studies. Absence of significant drug-carrier interaction was confirmed by infrared spectroscopic (IR) data.