Comparison of packed column supercritical fluid chromatography-tandem massspectrometry with liquid chromatography-tandem mass spectrometry for bioanalytical determination of (R)- and (S)-ketoprofen in human plasma followingautomated 96 well solid-phase extraction

The popularity of packed-column supercritical fluid, subcritical fluid, and enhanced fluidity liquid chromatographies (pcSFC) for enantiomeric separat ions has increased steadily over the past few years. The addition of a sign ificant amount (typically 20-95%) of a viscosity lowering agent, such as ca rbon dioxide, to the mobile phase provides a number of advantages for chira l separations. For example, higher mobile-phase now rates can often be atta ined without a concomitant loss in chromatographic efficiency since diffusi on coefficients, and optimum velocities, are typically higher in pcSFC, Ult ratrace enantioselective quantitation of drugs in biomatrixes is an ideal a pplication for these chromatographic attributes. To demonstrate the utility of this approach, a pcSFC tandem mass spectrometry (pcSFC-MS/MS) method wa s compared to a LC-MS/MS method for quantitation of the (R)- and (S)-enanti omers of ketoprofen (kt), a potent nonsteroidal, anti-inflammatory drug, in human plasma. After preparation using automated solid-phase extraction in the 96-well format, kt enantiomers were separated on a Chirex 3005 analytic al column using isocratic conditions. Validation data and study sample data from patients dosed with either orally or topically administered ketoprofe n were Generated using both pcSFC and LC as the chromatographic methods to compare and contrast these analytical approaches. Generally, most analytica l attributes, including specificity, linearity, sensitivity, accuracy, prec ision, and ruggedness, for both of these methods were comparable with the e xception that the pcSFC separation provided a roughly 3-fold reduction in a nalysis time. A 2.3-min pcSFC separation and a 6.5-min LC separation provid ed equivalent, near-baseline-resolved peaks, demonstrating a significant ti me savings for analysis of large batch pharmacokinetic samples using pcSFC.