Determination of absolute contents of candesartan cilexetil and amlodipine besylate in candesartan cilexetil and amlodipine tablets by quantitative nuclear magnetic resonance
Objective:To establish a method for determining the absolute contents of candesartan cilexetil and am-lodipine besylate in candesartan cilexetil and amlodipine tablets by qNMR Methods:The chemical shift δ 5.51 of candesartan cilexetil and δ 5.31 of amlodipine besylate were used as the quantitative peaks.δ 6.27 of maleic acid was the quantitative peak of internal standard.DMSO-d6 was used as the solvent.Results:The method was highly specific and the solvent peak,water peak and excipient peaks did not interfere with the quantitative peaks.Candesartan cilexetil showed a good linear relationship in the concentration range of 1.580 0-9.480 2 mg· mL-1,r=1.000,RSDs of precision,repeatability and stability were 0.070%,1.7%and 0.68%,respectively.The recoveries of low,medium and high concentration spiked were 98.1%-99.2%.The linear range of amlodip-ine besylate was 0.983 9-5.903 6 mg·mL-1(r=0.999 9).The RSDs of precision,repeatability and stability were 0.050%,1.8%and 0.79%,respectively.The recovery of amlodipine besylate was 99.1%-102.0%.This method was used to test two batches of reference preparations and one batch of sample from different sources.The results showed that the content of candesatan cilexetil was between 98.10%to 98.75%,and that of amlldip-ine besylate was between 98.98%to 99.60%.Conclusion:This method is rapid and accurate and it is not nec-essary to use a single component reference substance.This method provides a new method to determine the content to candesartan cilexetil and amlodipine tablets.
candesartan cilexetilamlodipine besilateabsolute contentquantitative nuclear magnetic resonance