solid dispersions

Nateglinide is an anti-diabetic drug that lowers the blood glucose levels by stimulating insulin secretion from pancreas. Because of low solubility and bioavailability, its usage is limited. In the present study solid dispersions of Nateglinide were prepared by solvent evaporation method and evaluated through various steps for biological correlation. Nateglinide solid dispersions were prepared using PEG 6000, Pluronic F 127 and Labrafil M 1944. A 3-factor, 3-level Central composite design employed to study the effect of each independent variable on dependent variables. X-ray diffraction was used to analyze the crystallinity and FTIR was used to analyze the drug and excipient compatibility. Scanning electron microscopy was performed to analyze the surface of solid dispersion samples. The correlation coefficient showed that the release profile followed Higuchi model (R2= 0.95836). From Korsmeyer peppas model, the release exponent, n was found to be 0.80635 (0.43 < n < 0.85) and followed anomalous behaviour and hence release mechanism was indicative of diffusion. From in vitro dissolution studies it was proved that a Nateglinide solid dispersion may achieve good formulation capability for pharmaceutical manufacturer by increasing solubility and dissolution rate. Key words: Nateglinide, Diabetes mellitus, solid dispersions, solubility, Central composite  

The purpose of the present study was to enhance the solubility and dissolution rate of a poorly water soluble drug by solid dispersion technique. Irbesartan was used as a model drug to evaluate its release characteristics from the formulations. Solid dispersions of Irbesartan with PEG 4000 and PEG 6000 were prepared by physical mixing, solvent evaporation and melting techniques in w/w ratios (drug: carrier). Characterization of the solid dispersions was carried out by Differential Scanning Calorimetry (DSC) and Fourier Transform Infra-Red spectroscopy (FTIR). The dissolution profiles of solid dispersions were compared with those of the pure drug. Solid dispersions of Irbesartan with PEG 4000 prepared by solvent evaporation technique at 1:1 ratio showed greater dissolution compared to other formulations. FTIR and DSC studies showed no significant interaction between Irbesartan and the hydrophilic carriers.

Solubility is an important physicochemical factor affecting absorption of drug and its therapeutic effectiveness. Drugs having poor aqueous solubility present one of the major confronts better absorption for good bioavailability of such drugs. The purpose of this study was to prepare and characterize solid dispersions of the poorly water soluble antihypertensive agent valsartan with water soluble carriers such as Kolliphor P 407, Kolliphor P 188, Kolliwax GMS II, Kolliphor HS15, HPMC AS and Soluplus in proportions viz. 1:1, 1:3, 1:5 (Drug: Carrier) with addition of 2% SLS to improve its aqueous solubility and rate of dissolution by solvent evaporation technique. All the formulations showed marked improvement in the solubility behavior and improved drug release. From all the formulations  SD6 was found to be optimized formulation  using soluplus as carrier based on the solubility and dissolution studies. The results obtained showed that the aqueous solubility and rate of dissolution was significantly improved when formulated in solid dispersion as compare to pure drug.