Simultaneous Spectrophotometric Determination of Levodopa and Benserazide in a Pharmaceutical

Abstract

ABSTRACT A method based on a partial least-squares calibration (PLS) for the simultaneous spectrophotometric determination of levodopa (I) and benserazide (II) in a commercially available pharmaceutical preparation is proposed. The calibration procedure was developped by using laboratory made mixtures of I and II, and optimized by selecting the most suitable wavelength range and spectral mode. The relative standard error of prediction (RSEP %) was 0.5% and 0.9% with a limiting reproducibility (R) of 4 10−6 M and 1.5 10−6 M for levodopa and benserazide, respectively The proposed method is straightforward, expeditious and precise. Its results are consistent with those provided by HPLC for the two analytes.