Investigations into new approaches for analyzing pharmaceuticals through the use of array detector imaging of high-performance TLC and well plates

Abstract

New methods of analyzing pharmaceuticals by high performance thin-layer chromatography and microplate imaging were investigated using array imaging technology. Both techniques provide high sample throughput over more traditional analytical techniques for the analysis of pharmaceuticals. HPTLC provides high sample throughput by performing separations in parallel using a planar stationary phase. Imaging the entire plate with a single exposure performs quantitation of the analytes in the chromatographic medium. Fluorescence and fluorescence quenching detection modes are presented by employing tetracyclines, famotidine, and several over the counter drugs as model compounds. Studies conducted include sensitivity, separation efficiency and reproducibility of the system. Microplate imaging allows for the quantitation of numerous analytes in parallel. In this technique, solutions containing the analyte of interest are deposited into numerous self-contained wells on microplates, also known as 96-wellplates or ELISA plates. Light is passed through the wells of the plate allowing for absorption, fluorescence, or fluorescence quenching. Imaging with an array detector enables the researcher to simultaneously quantitate each well in parallel. The reaction between primary amines, ampicillin and amoxicillin, and fluorescamine was investigated. Microplate imaging was also tested for quantitating analytes in the low UV region (254 nm).