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DEVELOPMENT AND VALIDATION OF RP-HPLC-PDA METHOD FOR THE SIMULTANEOUS ESTIMATION OF LEVODOPA, CARBIDOPAAND ENTACAPONE IN BULK AND PHARMACEUTICAL DOSAGE FORMS

Article history A simple, sensitive, rapid, economical LC/MS compatible analytical method was developed and validated for the simultaneous estimation of Levodopa (LD), Carbidopa (CD), and Entacapone (EC) in bulk and dosage forms by Reverse Phase High Performance Liquid Chromatography. The use of Phenomenex C18 reverse phase column (150 x 4.6mm, 5µm) with gradient mobile phase of 0.05% v/v o-phosphoric acid (A) and acetonitrile (B) enabled the efficient separation of the drugs within 15min. The eluents were monitored at 280nm and the retention times were 2.6, 5.7, 12.0 min for LD, CD, and EC respectively. Linearity was established in the concentration range of 10-50μg/mL, 5-25μg/mL, 20-100μg/mL for LD, CD and EC respectively, with correlation coefficients in the range of 0.997-0.999. Percent recoveries of LD, CD, and EC were in the range of 98-102 (RSD<2). The method was validated with respect to specificity, linearity, and limit of detection, limit of quantification, precision, robustness, and stability. Validation parameters fulfilled the regulatory requirements in all the cases. The method was successfully used for the analysis of LD, CD and EC in bulk and pharmaceutical dosage forms.