HILIC methods in pharmaceutical analysis.

In this review, hydrophilic interaction liquid chromatographic (HILIC) applications for pharmaceutical analysis are discussed. The HILIC technique uses an aqueous/organic modifier mobile phase with a high organic modifier fraction and a hydrophilic stationary phase (SP). In general, the SPs are silica or polymer based. The silica-based columns are most often applied and are divided into bare-silica particle, chemically bonded silica particle, and monolithic phases. The bare-silica columns are most frequently used. The much less applied polymer-based columns are also divided into particle and monolithic phases. In this review, the applications are grouped and discussed according to the SP type used. Whenever possible, the considered HILIC application is compared with other HILIC methods, e.g. on other SPs, and/or with other separation modes, for that application. The advantages and drawbacks of HILIC are also discussed, as well as the method validation issues, when executed.