Development and Validation of First Order Derivative Spectrophotometric Method for Simultaneous Estimation of Paracetamol and Tapentadol Hydrochloride in Tablet Dosage Form

A simple, precise, accurate and reproducible spectrophotometric method has been developed for Simultaneous estimation of Paracetamol and Tapentadol Hydrochloride by employing first order derivative zero crossing method in 0.1 N Sodium Hydroxide. The first order derivative absorption at 257.1 nm (zero cross point of Paracetamol) was used for quantification of Tapentadol HCl and 289.0 nm (zero cross point of Tapentadol HCl) for quantification of Paracetamol. The linearity was established over the concentration range of 15-35 μg/ml and 3-15 μg/ml for Paracetamol and Tapentadol HCl with correlation coefficient (r ² ) of 0.9989 and 0.9993 respectively. The mean % recoveries were found to be in the range of 99.52% - 99.88% and 98.39% - 98.66% for Paracetamol and Tapentadol HCl, respectively. Interday and intraday studies showed repeatability of the method. The method is successfully applied to pharmaceutical formulation, with no interference from excipients as indicated by the recovery study. All validation parameters were within the acceptable range. The proposed method has been validated as per ICH guideline and successfully applied to the simultaneous estimation of Paracetamol (PCM) and Tapentadol HCl (TAP) in their combined Tablet dosage form. The proposed method is recommended for routine analysis since it is rapid, simple, accurate and also sensitive and specific by no heating and no organic solvents are required. Also use of 0.1 N Sodium Hydroxide (NaOH) as a solvent makes it Cost effective and ver y economical method.