Improved chromatography of cyclosporine

A fast liquid chromatographic procedure for the measurement of whole-blood cyclosporine concentration is described. A sample preparation using solid-phase extraction requires 5.5 min of technical effort per sample. Chromatographic development is complete in 6 min. The results of this procedure correlate with those of a previously validated procedure. The slope of the correlation equation is 1.04, the gamma-intercept is -17, and the correlation coefficient is 0.99. Reproducibility of the procedure at midtherapeutic concentration is 5.5%, and sensitivity is 25 ng/ml. No chemical interference was observed from 33 drugs commonly co-administered during immunosuppression.