Biopharmaceutical Studies on Solid Dispersions of Nalidixic Acid in Modified Starches

The objective of the study is to improve the dissolution rate and efficiency and bioavailability of nalidixic acid (NA) and to evaluate three modified starches namely dextrin (D) β-cyclodextrin (β-CD) and hydroxyethyl starch (HES) as carriers for solid dispersions. Solid dispersions of NA in D, β-CD and HES were prepared by common solvent method and the dispersions were evaluated by TLC, IR, DTA, X-ray diffraction, moisture absorption, dissolution rate and bioavailability studies. The three modified starches were found to be non-hygroscopic, non-interacting carriers giving solid dispersions and effective in increasing the dissolution rate, efficiency and absorption rate of NA. A marked reduction in the crystallinity and crystal size of NA in the dispersions was observed.