Preformulation Studies of Cyperus Esculentus Starch Used As Disintegrant and as Binder in the Production of Paracetamol Tablets

Abstract

Starch is a naturally occurring polymer found in parts of the plants such as leaves, stems, tubers, and fruits. It is a commonly used excipient in pharmaceutical formulations because of its availability, affordability and inertness. Cyperus esculentus (tiger nut) is widely cultivated in the country especially in the northern part of Nigeria. Until recently, the use of tiger nut had been limited to food products and few pharmaceutical applications. This research is aimed at characterizing the starch isolated from Cyperus esculentus tubers, ascertaining its use as a binder and disintegrant in paracetamol tablet formulations, and to compare it with corn starch BP. Cyperus esculentus tubers, paracetamol powder, corn starch, gelatin, talc, magnesium stearate, and sodium benzoate were used for the study. Starch was isolated from Cyperus esculentus tubers. Physicochemical tests such as determination of densities, viscosity, pH, ash value, loss on drying, paste clarity, freeze thaw stability, browning and charring temperatures were done on the starch. Wet granulation method of tablet formulation was used to prepare paracetamol granules. The granules produced were characterized and then compressed into tablets. The formulated tablets were evaluated for various tablet properties such as hardness, thickness, friability, weight variation, disintegration time, dissolution rate as quality control measures. The physicochemical properties of starch from Cyperus esculentus were found to conform to BP standards for pharmaceutical grade starch. Results obtained from micromeritic studies such as angle of repose of 58.74 o, compressibility index of 16.0 % and Hausner’s quotient of 1.19 revealed that Cyperus esculentus is a poorly flowing powder. Paracetamol granules produced had good flowability as shown by angle of repose being < 50 o, Hausner’s quotient of <1.19 except for two batches that were 1.21 and 1.22. The values of compressibility indices ranged from 6.64 to 20.85 with most of the values falling below 16.0%. Evaluation of tablets showed that all batches passed the uniformity of weight test. The hardness of tablets was significantly affected by the binder concentration used in the formulation. The disintegration times were significantly affected by the concentration, method of incorporation and the type of disintegrant used. Friability values (< 1.0) obtained were within acceptable limits. The dissolution results showed that all batches of tablets released 80 % of the drug in the simulated gastric fluid (SGF) without enzymes, within 30 min. Drug release in the simulated intestinal fluid (SIF) without enzymes was less than 80% in 30 min. It can be concluded that Cyperus esculentus starch has acceptable powder properties, and provides excellent disintegrant (as shown by disintegration time of < 15 minutes) and binding properties in paracetamol tablet, without compromising drug release characteristics.