ABSTRACT
OBJECTIVE:To improve the detection method for the dissolution of dihydroartemisinin in Dihydroartemisinin and piperaquine phosphate tablets. METHODS:The dissolution experiment adopted paddle method using 0.1 mol/L hydrochloric acid so-lution 500 mL as solvent with rotating speed of 75 r/min and sampling time of 45 min. In sample pre-treatment,the volume of 3.6% sodium hydroxide solution was increased from 5 mL to 20 mL,and that of phosphoric acid was increased from 0.2 mL to 0.7 mL. HPLC was adopted to determine the dissolution of dihydroartemisinin. The determination was performed on YMC-Pack ODS-A column with mobile phase consisted of 0.02 mol/L disodium hydrogen phosphate solution(pH adjusted to 2.4 using phosphoric ac-id)-acetonitrile(65 : 35,V/V)at the flow rate of 1.0 mL/min. The detection wavelength was set at 237 nm,and column temperature was 30 ℃. The sample size was 20 μL. RESULTS:The linear range of dihydroartemisinin were 7.802-117.03 μg/mL(r=0.9999). The limit of quantitation was 2.0 ng,and the limit of detection was 0.6 ng. RSDs of precision and reproducibility tests were all low-er than 1.0%. The recoveries were 99.18%-100.46%(RSD=0.45%,n=9). Average dissolutions of dihydroartemisinin in 3 batch-es of samples were 94.9%,77.9%,89.6%,respectively. CONCLUSIONS:Improved method enhance the accuracy for the limit of sensitivity,dissolution and detection results.