Visible Spectrophotometric Methods Development for Quantification of Racecadotril in Commercial Formulations

Three direct, simple and sensitive visible spectrophotometric methods (M1,M2 and M3) are described for the assay of Racecadotril in pure and solid dosage forms. The method M1 is based on the formation of colored molecular complex with sodium nitroprusside in presence of acetaldehyde under alkaline conditions and exhibits λ max at 560nm. The method M2 involves oxidative coupling of drug with brucine in presence of sodium meta periodate and purple red colored species is formed and exhibits absorption maxima at 520nm. The method M3 is based on the formation of yellowish brown colored species by the drug with Folin reagent and exhibits absorption maxima at 450nm.Regression analysis of Beer-Lambert plots showed good correlation in the concentration ranges (8.0-40) μg/ml for methods M1, M2 and (20-60) μg/ml for method M3 respectively. The proposed methods are applied to commercial available formulations and the results are statistically compared with those obtained by the reported UV reference method (in methanol, λ max at 231nm) and validated by recovery studies. The results are found satisfactory and reproducible. These methods are applied successfully for the estimation of the Racecadotril in the presence of other ingredients that are usually present in dosage forms.