Kinetic approach for the enzymatic determination of levodopa and carbidopa assisted by multivariate curve resolution-alternating least squares

M. GRÜNHUT; M. GARRIDO; M. E. CENTURIÓN; B. S. FERNÁNDEZ BAND

ANALYTICA CHIMICA ACTA

ELSEVIER SCIENCE BV

Año: 2010 vol. 673 p. 33 - 39

0003-2670

A combination of kinetic spectroscopic monitoring and multivariate curve resolution- alternating least squares was proposed for the enzymatic determination of levodopa and carbidopa in pharmaceuticals. The enzymatic reaction process was carried out in a reverse stopped-flow injection system and monitored by UV-Vis spectroscopy. The spectra (292-600 nm) were recorded throughout the reaction and were analyzed by multivariate curve resolution-alternating least squares. A small calibration matrix containing nine mixtures was used in the model construction. Additionally, to evaluate the prediction ability of the model, a set with six validation mixtures was used. The lack of fit obtained was 4.3%, the explained variance 99.8% and the overall prediction error 5.5%. Tablets of commercial samples were analysed and the results were validated by pharmacopeia method (high performance liquid chromatography). No significant differences were found (á = 0.05) between the reference values and the ones obtained with the proposed method. It is important to note that a unique chemometric model made it possible to determine both analytes simultaneously.