comparative study of a new spectrophtometeric assay of alpha-methyldopa tablets manufactured by different companies

ABSTRACT

Many spectrophotometeric methods have been described for the determination of alpha-Methyldopa powder and tablets. However, most of these methods suffer from extraction, heating, time consuming for developing colour. The objective of this study is to eliminate previous factors and to determine a simple and sensitive Spectrophtometeric method. A simple, and sensitive Spectrophtometeric method is proposed for the analysis of reference standard and four commercial brands of alpha-Methyldopa. The method is based on the oxidation of alpha-Methyldopa by 0.25% K2CrO4, followed by oxidative coupling with 0.5% sulphanilic acid, to yield greenish-yellow product having maximum absorbance at 400 nm, and the absorptions were taken after 5 minutes. The system obeyed Beer's law over the concentration 10-175 mcg/ml. The relationship between absorbance and concentration was linear by applying regression linear equation. We calculated the concentration of the drug from the calibration curve. The common excipients and additives did not interfere with their determinations. The results obtained by the proposed method were compared statistically with official method [USP]. There were no significant differences in precision between them [p = 0.011]. The method was successfully used for the determination of alpha- methyldopa powder and tablets