New cyclosporine microemulsion randomized, cross-over bioequivalence steady-state study in renal transplanted patients.

A new microemulsion formulation of cyclosporine was compared with the marketed formulation in 18 stable renal transplanted patients. Aim of the study was not only to determine the bioequivalence between the two pharmaceutical preparations, but also to ascertain whether tested drug could maintain stable blood concentrations of cyclosporine. Renal transplanted patients under cyclosporine treatment from at least 12 months at a well individualized dosage (resulting in 90-200 ng/mL of blood level drug) have been selected. Patients received the same preceding dose of cyclosporine through both the two preparations according to a cross-over, randomized schedule during 4 weeks in two equally divided daily administrations. Serial blood samples were obtained over a 24-hour period at steady-state of each formulation. Cyclosporine concentrations were determined by a specific immunoassay method (FPIA) n whole blood taken in the last day of each cycle of treatment. Statistical comparisons of cyclosporine levels (using pharmacokinetic parameters) were cross-performed between formulations and days of blood test. Tested drug resulted bioequivalent with the reference marketed formulation. Furthermore, the study showed that tested drug maintained satisfactory stable blood concentrations of cyclosporine.