The commercially available oily solution of ciclosporin which has to be suspended before intake is disliked by some patients for bad taste and has a variable bioavailability. In this investigation the oral pharmacokinetics of ciclosporin and its main metabolites 1 and 17 of the oily solution (Sandimmun) and a soft gelatine capsule preparation of ciclosporin were compared in a crossover fashion in 10 kidney allograft recipients. The results demonstrate a bioequivalence of both formulations. In either case metabolite 17 had a significantly longer half-life than either ciclosporin or metabolite 1. At earlier time-points the concentration of ciclosporin could be best correlated with metabolite 1 and at later time-points with metabolite 17. Both metabolites were less correlated with each other in the late absorption phase of ciclosporin.
