The objectives of the present research work are to improve the solubility and dissolution rate of nateglinide. Solid dispersions of nateglinide were prepared by fusion method by using three selected hydrophilic meltable carriers vis-a-vis gelucire 44/14, poloxamer 188 and polyethyleneglycol (PEG6000). Sylysia 550 was used as an adsorbent. Solid dispersions were evaluated for solubility, phase solubility, flowability, compressibility, Fourier transform infrared spectra (FT-IR), differential scanning calorimetry (DSC). Solubility studies showed 10, 16 and 7 fold increase in solubility for gelucire 44/14, poloxamer 188 and PEG6000 based solid dispersions respectively. The Gibbs free energy ΔGtr° values were all negative for all the three carriers indicating spontaneous nature of solubilisation. FT-IR and DSC spectra showed that drug and carriers are compatible with each other. Solid dispersions exhibiting highest solubility for each were compressed into immediate release tablets by using crosscaramellose sodium as superdisintegrant. In vitro dissolution studies, exhibited more than 90 % drug dissolution in 1 h for poloxamer 188 based solid dispersion tablets (F11). The adsorbent, sylysia 550 may be used to impart good flow and compressibility to solid dispersions. Among the three carriers, poloxamer 188 exhibited better solubility and dissolution enhancement potential for nateglinide.
