Pharmacokinetics and tissue distribution of amphotericin B following oral administration of three lipid-based formulations to rats

The objective of this study was to assess the pharmacokinetics and tissue distribution of amphotericin B (AmB) in rats following oral administration of three lipid-based formulations (iCo-009, iCo-010 and iCo-011). The lipid-based formulations were administered to rats at a dose of 10 mg/kg and blood samples were withdrawn at predose, 1, 2, 4, 6, 8, 10, 12, 24, 48 and 72 h, after which the animals were sacrificed and the body organs were collected for AmB quantification using a validated HPLC method. Plasma pharmacokinetics parameters were determined using non-compartmental analysis. The disappearance of AmB from plasma was the slowest following the administration of iCo-010 with MRT of 63 h followed by iCo-009 then iCo-011 (36 and 27 h). The AUC(0-24h) of iCo-009 and iCo-010 was 1.5-2-fold higher than that of iCo-011. The kidney exposure was comparable between iCo-009 and iCo-010 and was higher than that of iCo-011. The lung exposure was the highest following iCo-010 administration as compared to that of iCo-009. The distribution of AmB from plasma to tissues resulted in a high accumulation of AmB overtime with slow back-distribution to plasma. The pharmacokinetics profiles varied among the three formulations, despite the similarity in lipid composition between iCo-010 and iCo-011 and the presence of Peceol (R) as a common component in the formulations. The administration of oral iCo-010 could lead to higher steady state concentrations in the tissues after multiple dosing, which could lead to enhanced eradication of tissue borne fungal and parasitic infections.