Stability-Indicating RP-HPLC Method for Analysis of Paracetamol and Tramadol in a Pharmaceutical Dosage Form

A simple, isocratic, rapid and accurate reversed phase high performance liquid chromatography method was developed for the quantitative determination of paracetamol and tramadol in commercial medicinal tablets. The chromatographic separation was achieved on an Inertsil C-18 (250 mm x 4.6 mm, 5 mu m) column using water pH 3.4 with orthophosphoric acid: methanol (60:40, v/v) as a mobile phase, and UV detection at 228 nm. The chromatographic resolutions between paracetamol and tramadol were found greater than five. The linear range for paracetamol and tramadol were 20.8-39.0 mu g/ml and 2.4-4.5 mu g/ ml was obtained with correlation coefficients >= 0.999 for each analyte. The retention time were found to be 2.1 and 3.9 min for tramadol and paracetamol respectively. Paracetamol and tramadol was subjected to stress conditions (hydrolysis (acid, base) oxidation, photolysis and thermal degradation) and the stressed samples were analyzed by use of the method. The major degradation was observed in acid and minor in base, thermal, oxidation and photolysis. The forced degradation studies prove the stability indicating power of the method.