Optimisation and characterisation of silica-based reversed-phase liquid chromatographic systems for the analysis of basic pharmaceuticals

Reversed-phase liquid chromatography using silica-based columns is successf ully applied in many separations. However, also some drawbacks exist, i.e. the analysis of basic compounds is often hampered by ionic interaction of t he basic analytes with residual silanols present on the silica surface, whi ch results in asymmetrical peaks and irreproducible retention. In this revi ew, options to optimise the LC analysis of basic pharmaceutical compounds a re discussed, i.e. eluent optimisation (pH, silanol blockers) and stationar y phase optimisation (development of new columns with minimised ionic inter actions). The applicability of empirical based, thermodynamically based and test methods based on a retention model to characterise silica-based rever sed phase stationary phases, as well as the influence of the eluent composi tion on the LC analysis of basic substances is described. Finally, the appl icability of chemometrical techniques in column classification is shown. (C ) 2000 Elsevier Science BN. All rights reserved.