Application of synthesized sodium carboxymethyl starch as a disintegrant in metronidazole tablets

Abstract

The objective of this study is to formulate immediate release metronidazole 400 mg tablets using synthesized sodium carboxymethyl maize starch as a disintegrant and to evaluate the physical properties of the tablets. Extracted maize starch was treated with monochloroacetic acid in the  presence of sodium hydroxide solution (NaOH) at varying concentrations (10 - 50%w/v) to produce sodium carboxymethyl starch (CMS). The various  modified maize starches were applied in tableting and a preliminary test of disintegration time was carried out. CMS 40 (Carboxymethyl starch modified with 40% NaOH) had the shortest disintegration time of 28.67 sec .Varying concentrations of CMS 40 (1 – 10%w/w) were employed as disintegrant in metronidazole tablet formulation. Model metronidazole tablets were formulated with 2%w/w CMS 40 as a disintegrant. Other batches of tablets containing sodium starch glycolate, maize starch as disintegrant and a fourth batch with no disintegrant were used for  comparison. Metronidazole tablets prepared with 2%w/w of CMS 40 exhibited the shortest disintegration time of 5.84 min. The t50 value obtained for tablets containing 2%w/w CMS 40 starch was 8.5 min. The corresponding t50 values obtained for tablets containing sodium starch glycolate, maize starch and no disintegrant were 21, 23 and 30 min respectively. Maximum concentrations of drug released after 45 min were 79.82, 67.52, 68.38 and 64.19% for tablets containing 2%w/w CMS 40, sodium starch glycolate, maize starch and no disintegrant. Analysis of variance (ANOVA) shows that differences in the values of t₅₀ or drug released after 45 min obtained for tablets containing the various disintegrants were significant at  P < 5%.

Keywords: Carboxymethyl maize starch, monochloroacetic, sodium hydroxide solution, Sodium starch glycolate, disintegration time, drug released.