High performance liquid chromatography of a cyclosporin A formulation on a porous graphitic carbon column

A porous graphitic column (PGC) column was employed as a stationary phase at high temperature to effect the separation of cyclosporin A (CyA) and cyclosporin U (CyU). A robust assay for the former in liposomes was also developed. Linearity was maintained at a concentration range of 2-20 mu g mL(-1) (r(2) = 1.00) with limit of quantification (LOQ) of 200 ng mL(-1). A. %CV (n = 6) of between 0.8-2.0 % showed a good precision of the system. The effects of different temperatures on the peak shape of CyA was also investigated. This showed the process of peak broadening to be kinetically controlled. The study has shown the PGC column to be stable for over 2500 injections which is an improvement over previous assays for CyA analysis.