THE SEPARATION OF DIHYDROFOLATE-REDUCTASE INHIBITORS AND THE DETERMINATION OF PK(A,1) VALUES BY CAPILLARY ZONE ELECTROPHORESIS

CZE was used as a method to separate eight dihydrofolate reductase inhibitors (DHFRI). Separation of the eight DHFRI was difficult to achieve and occurs only under very specific conditions. Baseline resolution occurred in 250 mM phosphate buffer of pH 2.1 at 13 kV. In an attempt to understand the mechanism of separation, pK(a,1) values have been determined and the effective hydrodynamic radii estimated by modeling the molecules. The consequential plot of Z/r versus the measured electrophoretic mobility gave a good linear correlation, thus demonstrating the fundamental nature of the separation mechanism.