On-column epimerization of dihydroartemisinin: an effective analytical approach to overcome the shortcomings of the International Pharmacopoeia monograph.
We developed a cryo-HPLC/UV method for the simultaneous determination of artemisinin (1), alpha-dihydroartemisinin (2alpha), beta-dihydroartemisinin (2beta), and a ubiquitous thermal decomposition product of 2 (designated as diketoaldehyde, 3), starting from the International Pharmacopoeia monograph on dihydroartemisinin. The method takes for the first time the on-column epimerization process of 2 into consideration. Chromatographic separation was obtained under reversed-phase conditions on a Symmetry C18 column (3.5 microm particle size) with a mobile phase consisting of acetonitrile-water 60:40 (v/v), delivered at 0.60-1.00 ml/min flow-rates, with ultraviolet detection at low wavelength (lambda = 210 nm). Low temperatures (T = 0-10 degrees C) were selected on the grounds of a diastereoselective dynamic HPLC (DHPLC) study performed at different temperatures, aimed at identifying the best experimental conditions capable of minimizing the on-column interconversion process.
Cabri
Walter
W
Analytical Development, R&D Department, sigma-tau S.p.A., Via Pontina km 30,400, 00040 Pomezia, Italy.
Ciogli
Alessia
A
D'Acquarica
Ilaria
I
Di Mattia
Michela
M
Galletti
Bruno
B
Gasparrini
Francesco
F
Giorgi
Fabrizio
F
Lalli
Silvana
S
Pierini
Marco
M
Simone
Patrizia
P
D000962:Antimalarials / Q000032:analysis; D037621:Artemisinins / Q000032:analysis* / Q000737:chemistry; D002626:Chemistry, Pharmaceutical / Q000379:methods; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation* / Q000379:methods; D013696:Temperature
D000962:Antimalarials; D037621:Artemisinins; C039060:artenimol