Abstract

Preparation and Evaluation of Starch Citrate: A New Modified Starch as Directly Compressible Vehicle in Tablet Formulations

Author(s): K. P. R. Chowdary, Veeraiah Enturi and S. Sujatha

The objective of the study is to prepare and evaluate starch citrate, a new chemically modified starch, as a directly compressible vehicle for tablets. Starch citrate prepared by reacting starch with citric acid at elevated temperatures, was found to be a white, crystalline and non-hygroscopic powder. Starch citrate powder of size 152 µm (80/120 mesh) exhibited excellent flow characteristics alone and after mixing drug and other excipients upto 30% and was found suitable for direct compression. Starch citrate was insoluble in water and aqueous fluids of acidic and alkaline pHs. It also exhibited good swelling (1500%) in water. It has no pasting or gelling property when heated at 1000 C in water for 30 min. Tablets of (i) gliclazide and (ii) pioglitazone were prepared by direct compression method employing starch citrate (70%) as directly compressible vehicle and the tablets were evaluated. The tablets of gliclazide and pioglitazone formulated employing starch citrate as directly compressible vehicle gave rapid and higher dissolution of the contained drug apart from fulfilling the official or GMP standards prescribed for uncoated tablets. A 1.68 and 3.92 fold increase in the dissolution rate (K1) was observed, respectively with gliclazide and pioglitazone tablets formulated by direct compression method employing starch citrate, when compared to the corresponding commercial brand. The starch citrate, a new modified starch was found to be a promising directly compressible vehicle for the preparation of tablets by direct compression method.