Simultaneous Spectrophotometric Estimation of Aceclofenac and Tizanidine Hydrochloride in Combined Tablet Dosage Form

Three simple, precise and economical spectrophotometric methods have been developed for the simultaneous estimation of Aceclofenac (ACF) and Tizanidine Hydrochloride (TZH) in combined tablet dosage form. The first method is simultaneous equation method, second method is based on the determination of Q-value and third method is Area under the Curve method. All methods utilize Methanol: Water (25:75) as solvent. Simultaneous equation method involves the measurement of absorbances at 273.5 nm (λ_max of ACF) and 227.5 nm (λ_max of TZH). The absorption ratio (Q-value) was determined at 218.5 nm (Iso-absorptivity point) and 227.5 nm (λ_max of TZH). For AUC method, wavelength range between 270–275 nm and 225–230 nm were selected for ACF and TZH respectively. Both the drugs obey Beer's law in the concentration ranges employed for these methods. All three methods were statistically validated and the results of recovery studies were found to be satisfactory. All the methods were found to be simple, rapid, and accurate and can be adopted in routine analysis of drugs in formulations.