Tablet binder properties of sodium carboxymethyl starch

Abstract

Sodium carboxymethyl starches were prepared from five natives starches (rice, glutinous rice, corn, tapioca and potato starches) to have three different degree of substitution. They were evaluated for their binding properties in tablet formulations using paracetamol as a model drug in comparison with the unmodified starches. It was found that various sodium carboxymethyl starches provided tablets having different physical properties. The tablets prepared with modified starches were harder and less friable than those prepared with native starches and the disintegration time met the requirement of pharmacopoeia. Moreover, the addition of the modified starches in the formulations by solution incorporation method provided better physical property tablets than when they were added by dry incorporation method. Among various types and degree of substitution of modified starches, modified glutinous rice starch at 0.35 degree of substitution was the best binder. It imparted the hardest tablet with short disintegration time. Furthermore, this modified glutinous rice starch was compared with polyvinylpyrrolidone K30 (PVP K30) and other modified rice starches commercially available and it was found that the modified glutinous rice starch was comparable with PVO K30 and had better properties than other modified rice starches commercially available. So, it was concluded that the new product of modified glutinous rice starch at 0.35 degree of substitution was suitable for use as a binder in paracetamol tablet formulation. The findings emerged from this work is another breakthrough in pharmaceutical application of starch. Modified glutinous rice starch have shown the most interesting property among the modified starches derived from different native starch. It could be used as the binder in tablet formulation by directly dispersing in cold water to form ready for use paste. It this starch product could introduced commercially, it would be beneficial by adding more value to agricultural products of the country.