Reversed-phase liquid chromatographic retention and selectivity surfaces. II. Deoxyribonucleosides.

By plotting capacity factors and selectivity factors as functions of temperature and pH or methanol concentration of the mobile phase, retention and selectivity surfaces of four deoxyribonucleosides were generated. Although changes in the methanol content had little effect on selectivity, changes in pH and temperature could be used to improve selectivity. However, changes in pH or temperature can be coupled with changes in methanol concentration to optimize the analysis time. In addition, by using lines of constant analysis time (isochrons), it was found that several sets of conditions will result in nearly identical retention times. These isochrons can be used to optimize the resolution of the solutes.

Preparative-scale high-performance liquid chromatographic separation and purification of 3'-azido-3'-deoxythymidine-5'-phosphate.

Crude 3'-azido-3'-deoxythymidine-5'-phosphate (AZT-P), obtained from direct phosphorylation of 3'-azido-3'-deoxythymidine (azidothymidine, AZT), was separated and purified by isocratic preparative high-performance liquid chromatography. The components in a 2.5-g load of crude AZT-P, obtained from work-up of the phosphorylation reaction, were separated in 50 min to give 1.8 g of 99.5% pure AZT-P. AZT-P was analyzed by high-performance liquid chromatography and by high-resolution nuclear magnetic resonance (1H, 13C, 31P) spectroscopy. The practical and rapid preparative chromatographic method is being applied to the purification of AZT-P and other antiretroviral dideoxynucleotides, used as intermediates in the synthesis of target-directed experimental drugs for the treatment of AIDS.