A comparative study of FK506 granules and capsules in renal transplant recipients

Nine renal transplant recipients in stable systemic condition on FK506 capsules were converted to FK506 granules in order to investigate the safety, efficacy, and pharmacokinetics of the granular formulation of FK506. The study period for the administration of FK506 granules was 4 weeks, and in principle, the oral dose was the same as that of the FK506 capsules. Renal graft function remained stable and no rejection signs were noticed while the patients were taking the granules. The area under the blood concentration-time curve (AUC), the maximum blood level (Cmax), and the time to reach Cmax (Tmax) after FK506 capsules and FK506 granules were, respectively, 93.1 +/- 66.4 and 97.0 +/- 89.1 ng.h/ml (P = 0.81), 12.7 +/- 7.1 and 15.2 +/- 11.7 ng/ml (P = 0.39), and 2.0 +/- 1.7 and 1.3 +/- 0.6 h (P = 0.29). The mean trough blood level during FK506 medication was 4.25 +/- 3.42 and 4.02 +/- 3.83 ng/ml, respectively, for the capsules and the granules. FK506 granules, a new formulation, showed an efficacy comparable to that of the FK506 capsular formulation.