Evaluation of Native and Carboxymethyl Yam (Dioscorea esculenta) Starches as Tablet Disintegrants

Abstract

Native yam starch and carboxymethyl yam starch (CMS) were evaluated as tablet disintegrants in comparison with various starches i.e., corn starch, tapioca starch and rice starch. Direct compression composition comprised dibasic calcium phosphate as a filler, each starch at various concentrations between 3-15% w/w as a disintegrant and magnesium stearate as a lubricant. Hydrochlorothiazide (HCTZ) was used as a model drug for drug dissolution testing. Tablet properties including hardness, friability, disintegration and dissolution were evaluated. The results showed that tablet hardness increased with the amount of starch in the tablets. Tablets containing yam starch and rice starch showed higher tablet hardness than other native starches, while the tablets containing CMS showed obvious superior hardness to that of the other starches. The disintegration of tablets containing native yam starch was faster than that of tablets with corn, rice, and tapioca starches. With increasing native starch concentrations, the disintegration of the tablets was found to be faster. Tablets with CMS disintegrated in a similar manner to those with native yam starch when the concentrations were up to 9% by weight. The disintegration was delayed with higher concentrations. The HCTZ tablet with yam starch as a disintegrant gave faster initial dissolution than the others. It can be concluded that native yam starch and its carboxymethyl derivative can be used as superior disintegrants in tablet formulation.