DEVELOPMENT AND VALIDATION OF LIQUID CHROMATOGRAPHIC METHOD FOR THE SIMULTANEOUS ESTIMATION OF LEVODOPA, CARBIDOPA AND ENTACAPONE IN COMBINED DOSAGE FORM

Abstract

An isocratic, reversed phase-liquid-chromatographic method was developed for the quantitative determination of
levodopa and carbidopa and entacapone in combined-dosage form. Agilent zorbax sb-C18 (250mm*4.6mm*5μ) column with
mobile phase containing water pH 4.0 adjusted with sodium dihydrogen orthophosphate: methanol in the ratio of (600: 400, v/v)
was used. The flow rate was 1.0 mL/min, column temperature was 25°C and effluents were monitored at 284 nm. The retention
times of levodopa and carbidopa and entacapone were 1.4min and 2.2min and 4.4min, respectively. The correlation co-efficient
for levodopa and carbidopa and entacapone were found to be 0.99 and 0.99 and 0.99, respectively. The proposed method was
validated with respect to linearity, accuracy, precision, specificity, and robustness. Recovery of levodopa and carbidopa and
entacapone in formulations was found to be 100% and 100% and 100% respectively confirms the non-interferences of the
excipients in the formulation. Due to its simplicity, rapidness and high precision. The method was successfully applied to the
estimation of levodopa and carbidopa and entacapone in combined dosage form.