HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY OF A CYCLOSPORINE-A FORMULATION ON A POROUS GRAPHITIC CARBON COLUMN

A porous graphitic column (PGC) column was employed as a stationary ph ase 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) o f 200 ng mL(-1). A. %CV (n = 6) of between 0.8-2.0 % showed a good pre cision of the system. The effects of different temperatures on the pea k shape of CyA was also investigated. This showed the process of peak broadening to be kinetically controlled. The study has shown the PGC c olumn to be stable for over 2500 injections which is an improvement ov er previous assays for CyA analysis.