Comparative Performances of Selected Chiral HPLC, SFC, and CE Systems With a Chemically Diverse Sample Set PHIL BORMAN, 1 BOB BOUGHTFLOWER, 2 KAYE CATTANACH, 3 KATHY CRANE, 4 KEITH FREEBAIRN, 1 GREG JONAS, 5 IAN MUTTON, 2 * ASHA PATEL, 1 MATT SANDERS, 5 AND DUNCAN THOMPSON 1 1 Strategic Technologies, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom 2 CASS, GlaxoSmithKline, Stevenage, Hertfordshire, United Kingdom 3 Chemical Development, GlaxoSmithKline, Tonbridge, Kent, United Kingdom 4 Strategic Technologies, GlaxoSmithKline, Dartford, Kent, United Kingdom 5 CASS, GlaxoSmithKline, New Frontiers North, Harlow, Essex, United Kingdom ABSTRACT Pharmaceutical companies have a continuous need to resolve new ra- cemates. Analysis may be required in aqueous and nonaqueous media, or in the pres- ence of several different sets of potentially interfering compounds. There is often a preparative requirement. For these reasons analysts may require a number of different separation systems capable of resolving a given pair of enantiomers. We wished to improve upon existing approaches that address this situation and undertook a program of work to screen over 100 racemates, selected for their chemical diversity, on over 100 different chiral HPLC, SFC, and CE systems. Here we report results of this comparison and illustrate the use of rapid gradient screening as a valuable tool for chiral method development. Chirality 15:S1–S12, 2003. © 2003 Wiley-Liss, Inc. KEY WORDS: comparison; chiral phases; chiral selectors; HPLC; SFC; CE From the inception of a series of new compounds through to the end of a product lifetime, there exists in the pharmaceutical industry a continuing need for chiral reso- lution for various purposes and in diverse matrices. Early experimental synthetic programmes require support in a number of ways: monitoring stereoselective reactions, semipreparative isolation and characterisation of novel en- antiomers from racemates to allow initial activity and toxi- cological screening, and the resolution of chiral synthons and intermediates on a preparative scale. Chemical devel- opment requires analytical methods capable of determin- ing low levels of a distomer in the presence of the eutomer. As development proceeds, such methods must increas- ingly be robust and suitable for inclusion in exacting speci- fication procedures. They must also in time demonstrate selectivity with respect to synthetic impurities and degra- dation products. Analytical methods must be developed that enable the metabolism and pharmacokinetics of the drug to be followed in a stereospecific manner, requiring trace analysis in a variety of complex biological media such as blood, tissue, and urine. Finally, robust methods are required to meet all manufacturing specifications of the various formulations in which an active component might be presented. In general, an analyst supporting early stage chemistry will see many new structures, but relatively few repeat analyses, whereas in production QC analyses must be made of numerous samples of a single compound. In both cases, rapid response is critical if synthetic pro- grammes are not to be delayed, or product not to be passed fit for delivery. With this perspective in mind, it is clear that it would be beneficial to identify as early as possible some alternative means for resolving a given racemate. For example, an initial method may be subject to interferences from poten- tial impurities arising from improvements to the synthetic route, or a normal phase method developed for preparative work may prove poorly suited to analysis of urine samples. For this reason, our early research programmes have for a number of years been supported by using the approach adopted first by Whatley. 1 New racemates are screened against a number of chiral high-performance liquid chro- matography (HPLC) phases mounted in a valve-selectable arrangement that allows the column offering the best sepa- ration to be identified. This has proved particularly benefi- cial when choosing a column for preparative work. We have also found supercritical fluid chromatography (SFC) and capillary electrophoresis (CE) to be valuable for nu- merous chiral applications, and so wished to consolidate our knowledge and practice in these areas. The comprehensive review by Gubitz and Schmid 2 of *Correspondence to: Ian Mutton, Analytical Sciences, CASS, Discovery Research, GlaxoSmithKline, Gunnels Wood Rd, Stevenage, SG1 2NY UK. E-mail: Ian.M.Mutton@gsk.com Received for publication 16 December 2002; Accepted 24 March 2003 CHIRALITY 15:S1–S12 (2003) © 2003 Wiley-Liss, Inc.