A simple, precise, accurate and reproducible spectrophotometric method has been developed for simultaneous estimation of rosuvastatin calcium and aspirin by employing first order derivative zero crossing method in methanol. The first order derivative absorption at 256.3 nm (zero cross point of aspirin) was used for quantification of rosuvastatin calcium and 243.2 nm (zero cross point of rosuvastatin calcium) for quantification of aspirin. The linearity was established over the concentration range of 4-24 μg/ml and 10-60 μg/ml for rosuvastatin calcium and aspirin with correlation coefficient r 2 0.9988 and 0.9983, respectively. The mean % recoveries were found to be in the range of 99.44% – 100.83 % and 99.51– 101.11 % for rosvastatin calcium and aspirin, respectively. The proposed method has been validated as per ICH guideline and successfully applied to the estimation of rosuvastatin calcium and aspirin in their combined capsule dosage form.
