Author(s): Vinayaka D.G, Satishkumar Shetty A, Manzoor Ahmed, Anil Kumar S.M.
Two simple, precise and accurate spectrophotometric methods have been developed and validated for the simultaneous Determination of Brimonidine tartrate (BRT) and Timolol maleate (TIM) in bulk and ph armaceutical formulations. Namely Simultaneous equation (method 1), Q-absorbance ratio (method 2). In method 1, both the drugs exhibit good linearity over the concentration range of 4-20 mg/mL and 1 to 50 mg/mL of Brimonidine tartrate and Timolol maleate at 255nm (r2 =0.9998 and 0.9998 respectively) and 295nm (r2 =0.999 and 0.999 respectively) wavelengths respectively. Method 2, involves the formation of Q-absorbance equation using the absorptivity values at 271nm (isoabsorptive point) (r2 =0.999 and 0.9998 respectively) and 295nm (?max of Timolol maleate) (r2 =0.9998 and 0.999 respectively) and Beer’s Lambert’s law was obeyed over the concentration range of 4-20 mg/mL and 10-50 mg/mL respectively. The proposed methods were validated according to ICH guidelines for evaluation of accuracy, precision, sensitivity. These are economically viable methods that do not require any prior separation procedure and costly solvents.