Study Of The Contents In Compound Dihydroartemisinin Tablets By HPLC

OBJECTIVE :Compound dihydroartemisinin tablet (Artekin) is the new type antimalarial drug. There are three available compositions in it, and they are dihydroartemisinin, piperaquine phosphate and trimethoprim. In Chinese current new drug criterion they are determined by UV specterphotometry after derivatization , UV specterphotometry and HPLC separately. In this method every composition was determined separately , many errors would be imported into the process and the manipulation would be difficult.Dihydroartemisinin is a sesquiterpene lactone characterized by the presence of endoperoxide that is associated with a potent antimalarial activity. It is optics alive and has a process of anomeric conversion from B-epimer to a-epimer in organic solvent. Because it has no sensitiveand differential group for UV specterphotometry, it can not be determined by UV specterphotometry directly.There is no report of simultaneous determination of piperaquine phosphate and trimethoprim in compound dihydroartemisinin tablets by HPLC until now.Our work is to build a sensitive, specific, accurate, simple, and suitable HPLC-ELSD method for the determination of DHA and HPLC-DAD method for PQP and TMP in compound dihydroartemisinin tablets and make the criterion consummate.METHOD:The quantitative analysis of DHA was based on the peak area and the following standard curve was made. Theoretical plates of P-DHA are no less than 6000. The Lichrospher C18 column (150mm x 4.6mm, 5um) was used. The mobile phase was consisted of acetonitrile and water (8:2) , the velocity of flow was l.Oml'min"1, temperature of the column was 20 C, and injection volume was 20ul. The drift tube temperature of ELSD was 63C, the gas flow was l.SL'min"1 and the impactor was off.The determination of PQP and TMP was processed by peak area and external standard method was used. Both PQP and TMP exhibited good peak shape with high peak efficiency as a consequence ( 4000 theoretical plates) . The Lichrospher CN column (250mmX4.6mm, 5 urn) wasused. The mobile phase was consisted of 0.04mol.l-1 potassium dihydrogen phosphate (adjust to pH 2.5 +0.1 with diluted phosphoric acid) and acetonitrile (90 : 10) . The detective wavelength was at 280nm, the velocity of flow was 1.0ml.min-1, the temperature of the column was 30C, sensitivity of DAD detection was 0.08AUFS and injection volume was 20ul.RESULTS:The precision of DHA was good and RSD was 1.6%. The recoveries was 98.7%. The linear ranges of dihydroartemisinin was 1.1~5.8ug, linear regression equation was Y = 11.8849 + 1.9638 X, r = 0.9987. When the Signal-to-Noise was 3, LOD (limit of detection) of DHA was 58ng.The precision of PQP and TMP were good, and RSD were 0.08% and 1.92%, respectively. The recoveries of piperaquine phosphate was 99.6%, and of trimethoprim was 98.6%. The linear ranges of piperaquine phosphate was 1.6 ~ 8ug , the linear regression equation obtained was A = 9.75X103C - 4.58X104, r = 0.9999; and of trimethoprim was 0.45 - 2.25ug, linear regression equation was A =1.838 X104C + 1.370 X104, r = 0.9999. When the Signal-to-Noise was 3, LOD of piperaquine phosphate was 48ng and of trimethoprim was 40ng, respectively.COCLUSION:The HPLC-ELSD method for DHA and HPLC-DAD method for PQP and TMP have been developed and validated. They are sensitive, specific, accurate, simple, and suitable for the determination of the three compositions in compound dihydroartemisinin tablets.