Stability-Indicating HPLC Method for the Simultaneous Determination of Paracetamol and Tramadol Hydrochloride in Fixed-Dose Combination Tablets

An accurate, sensitive, precise and isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) method, using a UV detector for analysis of paracetamol and tramadol hydrochloride in combination tablets has been developed and validated. The best separation was achieved on Zorbax SB C 18 250 mm × 4.6 mm, 5-μm particle, with 30: 70 (v/v) of acetonitrile: 1% trifluoroacetic acid as the mobile phase, at a flow rate of 1.5 ml/min. The detection wavelength was set at 271 nm. The method was validated according to the International Conference on Harmonization (ICH) guidelines. The response was a linear function of concentration over the range of 325 – 2112.50 ppm for paracetamol and 37.5 – 243.8 ppm for tramadol hydrochloride. The correlation coefficient (r 2) was found to be 0.9998 for paracetamol and 0.9961 for tramadol hydrochloride. The limits of detection and quantitation were found to be 35.80 ppm and 108.49 ppm for paracetamol and 4.14 ppm and 12.54 ppm for tramadol hydrochloride. The drug was subjected to hydrolytic and thermal stress and was found to decompose slightly under both acidic and basic hydrolytic stress conditions and also under thermal stress. The degradation products produced as a result of the hydrolytic and thermal stress did not affect the detection of both paracetamol and tramadol hydrochloride, and the assay could thus be regarded as stability-indicating. The developed method was used to assay a sample of fixed-dose combination tablets and was found to be suitable for application in the analysis of fixed-dose combination tablets of paracetamol and tramadol hydrochloride for quality control purposes.