Development of a Stability-Indicating HPLC Method for Simultaneous Determination of Amlodipine Besylate and Atorvastatin Calcium in Bulk and Pharmaceutical Dosage Form

solutions in methanol were analyzed right after its preparation 1, 2 and 3 days after at 5°C.The change in standard solution peak area response over 3 days was (0.57 and 0.58%) for Amlodipine Besylate, Atorvastatin Calcium respectively.Their solutions were found to be stable for 3 days at 5°C at least (Figure 3).