A Validated Rp-hplc Method for Simultaneous Estimation of Paracetamol and Diclofenac Potassium in Pharmaceutical Formulation

A simple, selective, rapid, precise and economical reverse phase high performance liquid chromatographic method has been developed for the simultaneous estimation of paracetamol and diclofenac potassium from pharmaceutical formulation. The method was carried out on a Phenomenex LUNA C18 (25 cm x 4.6 mm i.d., 5 μ) column with a mobile phase consisting of acetonitrile: sodium dihydrogen ortho phosphate (adjusted to pH 3.5 using orthophosphoric acid) in the ratio of 70:30 v/v at a flow rate of 1.0 mL/min. Detection was carried out at 278 nm. Aceclofenac was used as an internal standard. The retention times of paracetamol, diclofenac potassium and aceclofenac were 5.9, 9.4 and 3.12 min, respectively. The developed method was validated in terms of accuracy, precision, linearity, limit of detection, limit of quantitation and solution stability. The proposed method can be used for the estimation of these drugs in combined dosage forms.