The Robustness and Comparability of a Novel Rapid Reversed‐phase HPLC Drug‐screening Method Compared with Existing Systems

Abstract

Acidic and basic drugs have been run on a novel non-buffered reversed-phase HPLC system. Variations in eluent pH, column temperature and eluent composition were used to demonstrate the excellent robustness of the system. The repeatability of the 16 nitro-n-alkanes used to assign index values to the retention times of acidic and basic drugs were not affected by the varied applied conditions (mean standard deviation less than 0.1 min). Due to the low operating pH of the system (2.2) the largest variation in retention index was seen to occur with the basic standard drug set, 7 retention index units between the two extremes of pH. Retention indices of 73 drugs run on different HPLC equipment using an ODS column from a different manufacturer, gave a correlation r = 0.990 with the retention indices of the same drugs run on the system used here. A correlation r = 0.977 was obtained for 48 common retention indices given by a buffered system published by other workers. A data set of 168 drugs run on the previous ODS system was used to generate a database of retention indices. These retention indices were obtained from the equations that described the correlations between this data set and that of other workers. For 115 drugs run on the system described here that are also present in this compilation, a correlation r = 0.945 was obtained from linear regression between them.