Preparation and Evaluation of Carboxymethylated Dioscorea bulbifera Starch as Disintegrant in Ibuprofen Oral Tablet

Background and Objective: Dioscorea bulbifera (climbing yam) is a species of yam not too common to many but is an edible meal in the Southeast and South-South Regions of Nigeria. This work was to modify this yam starch by carboxymethylation and use the starch as a disintegrant in a given tablet formulation. The effect of the reaction conditions of amount of sodium hydroxide and time of reaction on the degree of substitution and properties of the modified starch was investigated. Materials and Methods: Dioscorea bulbifera starch was obtained from its tubers purchased locally, modified by carboxymethylation (varying the concentration of sodium hydroxide and time of reaction) and evaluated for physicochemical properties, swelling power and photomicrography. The degree of substitution of the carboxymethylation reaction of the native starch was determined and the modified starch with desired properties was selected for use as a disintegrant in the formulation of ibuprofen oral tablet. Ibuprofen granules were prepared by wet granulation and then evaluated. Ibuprofen compacts were formed, the disintegration parameters determined and these compared with that of a commercial ibuprofen brand. Results: The degree of substitution on the starches by the carboxymethylation reaction was in the range of 0.01-0.35. Carboxymethylation significantly improved the flow properties, water interaction properties (swelling, hydration capacity) and particle size of starches (79-188 μm) but lowered the viscosity (2.86-3.48 mPas) when compared with the native. Conclusion: Carboxymethylation improved the swelling index of Dioscorea bulbifera starch and would be a good alternative to conventional starch as a disintegrant.