A rapid and simple UV spectrophotometric method to estimate both the drug candidates without prior separation by the method of simultaneous equations was developed and validated. For azilsartan medoxomil, the regression equation (A = 0.00973C + 0.00034) with a correlation coefficient of 0.99995 and an R² of 0.9999 indicates an exceptional linear relationship among concentration and absorbance across the 20-120 µg/mL range. For chlorthalidone, the results are particularly remarkable. The regression equation (A = 0.0128C + 0) with a correlation coefficient of exactly 0.9999 and an R² of 0.999 represents a perfect linear fit. For intra-day precision, the % RSD values were 0.8% for azilsartan medoxomil and 1.2% for chlorthalidone, indicating excellent repeatability. The recovery studies yielded highly satisfactory results across all three spiking levels. For azilsartan medoxomil, mean recovery values aligned from 100.0% to 100.5%, with % RSD between 0.7% and 1.6%. For chlorthalidone, mean recovery values aligned from 99.5% to 101.0%, with % RSD values between 0.6% and 1.6%.
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