Microemulsion formulation of cyclosporine in pediatric liver transplantation.

The oral bioavailability of Sandimmun can be impaired by cholestasis, external biliary diversion, and diarrhea. We report two cases of pediatric liver transplant recipients who experienced chronic rejection and diarrhea secondary to proximal bowel resection. These conditions resulted in poor oral absorption of Sandimmun; the children were converted to the new oral microemulsion formulation Neoral, which significantly improved oral absorption, allowing intravenous cyclosporine weaning and patient discharge. Comparative pharmacokinetic studies were performed in both cases, and the relative Neoral/Sandimmun bioavailabilities were 32.9 and 5.4, respectively. Accordingly, Neoral may constitute to good alternative to ensure the effectiveness of oral cyclosporine administration, particularly in liver-transplanted children with severe cholestasis or shortened small bowel.