The generation of large numbers of samples during early drug discovery has increased the demand for rapid and selective methods of analysis. Liquid chromatography-tandem mass spectrometry (LC-MS-MS), because of its sensitivity, selectivity, and robustness, has emerged as a powerful tool in the pharmaceutical industry for many analytical needs. This work presents a high-throughput selected reaction monitoring LC-MS bioanalytical method for the determination of idoxifene, a selective estrogen receptor modulator, and its pyrrolidinone metabolite in clinical human plasma samples. The described method uses short, small-bore columns, high flow rates, and elevated HPLC column temperatures to perform LC separations of idoxifene and its metabolite within 10 s/sample. Sequential injections were accomplished with a 215/889 multiple probe liquid handler (Gilson, Inc.), which aspirates eight samples simultaneously and performs its rinse cycle parallel to sample injection, resulting in minimum lag time between injections. This high-throughput method was applied to the determination of idoxifene and its metabolite in clinical human plasma samples. Sample preparation employed liquid/liquid extraction in the 96-well format. Method validation included determination of intra- and interassay accuracy and precision values, recovery studies, autosampler stability, and freeze-thaw stability. The LOQ obtained was 10 ng/mL for idoxifene and 30 ng/mL for the metabolite. Using idoxifene-d5 as an internal standard, idoxifene showed acceptable accuracy and precision values at QC level 1 (QC1, 15 ng/mL), level 2 (QC2, 100 ng/mL), and level 3 (QC3, 180 ng/mL) (85.0% accuracy +/- 12.0% precision, 95.1 +/- 4.9%, and 90.3 +/- 4.7%, respectively). The pyrrolidinone metabolite also showed acceptable accuracy and precision values (using no internal standard for quantitation) at QC1 (60 ng/mL), QC2 (100 ng/mL), and QC3 (180 ng/mL) (104.9 +/- 14.4%, 91.1 +/- 13.0%, and 90.8 +/- 12.2%, respectively). The validated method was applied to the analysis of 613 human clinical plasma samples. An average run time of 23 s/sample (approximately 37 min/ 96-well plate or over 3,700 sample/day) was achieved. The successful validation presented indicates that rapid methods of analysis can efficiently and reliably contribute to the fast sample turnaround required for high sample number generating processes.

Preparative HPLC and HPLC-MS are well established as the methods of choice for purification of pharmaceutical library compounds. Recent advances in supercritical fluid chromatography (SFC) have now made SFC a viable alternative to HPLC for this application. One of the potential arguments for using SFC in place of, or in addition to, HPLC is that it may offer different selectivity and thus has the potential for improved separation success rates. In this paper, we examine relative success rates for SFC and HPLC in obtaining adequate selectivity for successful separation. Our results suggest that use of SFC in addition to HPLC may result in a slight (1-2%) improvement in success rate compared to use of HPLC alone.

Preparative HPLC-MS is often the method of choice for purification of small amounts (<100 mg) of diverse new molecules, such as compound libraries for drug discovery. The method is robust, well proven, and widely applicable. In contrast, preparative supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) has seen only slow acceptance for the same application—despite some potential scientific and economic advantages. One of the reasons for slow adoption of SFC-MS is the lack of well-proven, robust, and commercially available instrumentation. In early 2009, TharSFC (a Waters Company, Pittsburgh, PA) introduced a new fully integrated system for preparative SFC-MS: The SFC-MS Prep-100. We report herein an objective evaluation of the SFC-MS Prep-100, including tests for pump and autosampler performance, sample recovery, sample carryover, fraction triggering, detector/fraction collector synchronization, and overall robustness. Our results suggest that the SFC-MS Prep-100 represents a significant advance over previous generation instrumentation.

All-dielectric high reflector coatings produced by plasma plating were evaluated for their applicability as low loss, UV stable intracavity end mirrors. Although ultimately intended for ion laser applications, the design wavelength was set at 633 nm, taking advantage of existing scatter and total loss instrumentation. The total loss using an optoacoustic loss instrument was tracked during exposure to a low pressure mercury lamp simulating the UV environment of an optical cavity. This source has its strongest emission at 248 nm. The reflectors consisted of quarterwave stacks of alternating high and low index materials with halfwave overcoats of low (silica). Four high index materials were examined: titania, zirconia, tantala, and hafnia. Titania/silica stack scatter losses exceeded 2000 ppm. No further testing was attempted with this combination. The zirconia stack scatter averaged 550 ppm, while the tantala and hafnia could be produced with loss averaging ~200 ppm. In selected areas the scatter was under 100 ppm. After annealing at 400°C for 1 h, the total losses closely matched the combined losses from scatter and transmission, with the bake having no measurable effect on scatter. In standard plasma plating deposition conditions, the zirconia, tantala, and hafnia all had similar UV exposure characteristics suggesting a common loss mechanism. Each reached a saturation loss level ~500 ppm higher than its starting value after ~30 min of UV exposure. Unlike conventionally deposited films which degrade rapidly under UV exposure, samples produced omitting the halfwave overcoat had UV-induced losses of only ~100 ppm with a time constant of <2 min.

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