Rapid and direct analysis of statins in human plasma by column-switching liquid chromatography with restricted-access material

• A lab made RAM-BSA column showed high protein exclusion capacity and appropriate micromolecules retention.
• The column-switching system allowed direct injection of human plasma in the liquid chromatograph.
• Only 16 min was need to sample preparation and separation of the four statins.
• The developed method was validated, showing selectivity, linearity, precision and accuracy.

This study presents the development of a column-switching liquid chromatographic method with direct injection of human plasma for simultaneous determination of four statins (lovastatin, pravastatin, rosuvastatin and simvastatin), the main class of drugs used in the treatment of hyperlipidemia. By using a C18 (30 mm × 4.6 mm, 15 μm) a lab made bovine serum albumin restricted access material (RAM) column was prepared and compared with a commercial alquil-diol silica RAM column (C18, 25 mm × 4.0 mm, 25 μm) in terms of their protein exclusion capacity and micromolecules retention. Foreflush and backflush modes were compared for both RAM columns to the number of theoretical plates, asymmetry, resolution and chromatographic run time. The developed method was validated in the range from 125 to 876 ng mL−1 for lovastatin, rosuvastatin and simvastatin, and from 500 to 2000 ng mL−1 for pravastatin, presenting selectivity, precision and accuracy intra and inter-run. Total analysis time (sample preparation and chromatographic separation) was only 16 min when the backflush mode was employed in the column-switching system.