Formulation and application of a gradient reversed-phase HPLC method development strategy to the analysis of HMG-CoA reductase inhibitor drug substances

Abstract

A method development strategy for reversed-phase high performance liquid chromatography (HPLC) using gradient elution has been formulated and tested. A selectivity screening study was performed using a mixture of thirteen compounds to try to understand the effect of chromatographic factors like gradient time, column temperature, solvent type, aqueous mobile phase pH and stationary phase type on the retention of the compounds using a full factorial experimental design in which both main effects and significant interactions were identified. In general, it was found that the aqueous mobile phase pH is the factor that has the strongest contribution to retention and selectivity changes of a separation in the presence of ionizable substances. Solvent type was also found to have an important contribution to both retention and selectivity changes. Gradient time was found to have a relatively small contribution to changes in selectivity of the separation but a strong effect on the retention while both temperature and stationary phase type was considered to have relatively small contributions to changes in both selectivity and retention of the separation.