A UV Spectrophotometric method for simultaneous determination of Ibuprofen and Paracetamol concentration in suspensions

INTRODUCTION: Paracetamol is a standard antipyretic and analgesic which is widely used since the 19th century. Currently, paracetamol is the first-line treatment for pain management of different types. Ibuprofen, on the other hand, is an antipyretic and an analgesic. It is safe and has been used in the treatment of a number of conditions including mild to moderate pain, dysmenorrhea, inflammations and fever to name few. METHODS: This study aimed at developing and validating a simultaneous UV spectrophotometric method for analysis of ibuprofen and paracetamol in fixed-dose combination suspensions. The proposed method is based on the simultaneous equation principle, which involves measurement of absorbance at wavelengths of maximum absorbance for ibuprofen and paracetamol. The method was validated for linearity, accuracy, repeatability, intermediate precision and robustness as per USP and ICH guidelines. RESULTS: The two molecules showed wavelength of maximum absorbance at 222 nm and 243 nm for ibuprofen and paracetamol respectively, using phosphate buffer as a diluent. The method was also linear (R2≥0.995), precise (RSD ≤ 2), and robust with accuracy ranging between 98.1%-105% and 109.8 %- 134.9% for paracetamol and ibuprofen, in the range of 0.0032 – 0.0048 mg/ml for ibuprofen and 0.004-0.006 mg/ml for paracetamol, respectively. CONCLUSION: We have developed an accurate and robust method which can be used to analyze quantitatively paracetamol in suspensions which contain both paracetamol and ibuprofen. The limits of quantification of this method cover the concentration range recommended by the USP (80%- 120%), which justifies the application of the method in routine analysis.