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Shenaz Nunhuck
Christine Prosser Paula Garcia John Comer Shenaz Nunhuck Darren Edwards Toni Llinàs


The role of chromatography in physicochemical characterisation

Shenaz Nunhuck, Computational Analytical and Structural Sciences, GlaxoSmithKline

During the early phase of drug discovery it is becoming increasingly important to acquire the physicochemical profile of molecules. It has long been recognised that there is a strong relationship between lipophilicity and various “developability” parameters, such as permeability, solubility, oral absorption, bioavailability, CNS penetration, metabolism, etc. For this purpose there is a strong interest in developing high throughput fully automated methods for fast and reliable measurements of lipophilicity.

The HPLC technique has a great potential to determine various types of lipophilicity through retention time measurements. Various stationary phases can be used, such as C-18, octanol, immobilised artificial membrane (IAM), human serum albumin (HSA), alpha-acid glycoprotein (AGP), etc. The mobile phase pH can be altered for the investigation of the effect of charge and to obtain a quantitative measure of acid/base character. The dynamic range can be increased by applying a fast gradient to alter the mobile phase polarity and thus decrease the analysis time without decreasing precision. The measured retention times can be converted into reproducible partition data (e.g. Chromatographic Hydrophobicity Index, CHI) using calibration.

The HPLC based biomimetic lipophilicity measurements such as protein binding and IAM partitioning has proved to be useful to understand compound’s distribution in vivo. Parallel HPLC systems and automation make it possible to determine these various “flavours” of compound lipophilicity in minutes. These large amounts of HPLC based lipophilicity measurements are extensively used in the early stages of the drug discovery process during compounds’ selection processes.

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Last modified: 28 April 2008