The reversed-phase retention behavior of some atypical antipsychotic drugs

Abstract

As discussed elsewhere [3], the literature on the TLC analysis of these drugs is not extensive. The purpose of the research discussed in this paper was to investigate retention data of atypical neuroleptics – amisulpride, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone (Figure 1) – on RP18, RP8, RP2, CN, diol, and NH2 plates with mixtures of phosphate buffer and six modifiers (acetone, acetonitrile, dioxane, ethanol, methanol, and tetrahydrofuran) as mobile phases. For RP18 and RP8 plates the linearity of relationships between RM and the volume fraction of the modifier, the logarithm of the volume fraction of the modifier, the molar fraction of the modifier, and the logarithm of the molar fraction of the modifier was tested. The results usually fitted the Snyder–Soczewinski equation with r > 0.95. The best separation was achieved on RP8 plates with 40 + 60 (v/v) dioxane–pH 3.51 phosphate buffer as mobile phase. This work is a continuation of our previous research on the normal-phase TLC of these drugs.