Pharmacokinetics and biodistribution of amphotericin B in rats following oral administration in a novel lipid-based formulation.
OBJECTIVE
To assess the pharmacokinetics and biodistribution of amphotericin B (AmB) following oral administration in a novel mono/diglyceride-phospholipid formulation and to compare with intravenous (iv) administrations using commercial formulations.


METHODS
Rats were allocated into the following treatment groups: oral gavage of AmB dispersed in mono/diglyceride-phospholipid formulation at doses of 4.5 and 10 mg/kg; iv bolus administration of 0.8 mg/kg Fungizone; iv bolus of 5 mg/kg Abelcet and iv bolus of 5 mg/kg AmBisome. Blood was sampled from jugular vein cannula at certain time points. The animals were sacrificed 72 h following administration of AmB and multiple tissues were harvested. The concentration of AmB in plasma and tissues was determined by means of HPLC. The plasma creatinine concentrations were determined using an enzymatic kit.


RESULTS
The pharmacokinetics and tissue distribution of AmB following iv administrations of the commercial formulations were found to be highly formulation dependent. The terminal half-life and biodistribution of orally administered AmB in a mono/diglyceride-phospholipid formulation resembled those of Fungizone. The larger volume of the co-administered lipid-based formulation in the case of the higher dose of orally administered AmB resulted in flip-flop kinetics and in preferential distribution into the kidneys. No nephrotoxicity was detected for any formulation and route of administration.


CONCLUSIONS
Oral administration of AmB in a mono/diglyceride-phospholipid formulation to rats resulted in significant intestinal absorption into the systemic circulation with pharmacokinetic and biodistribution properties similar to a micellar iv preparation.
Gershkovich
Pavel
P
Faculty of Pharmaceutical Sciences, The University of British Columbia, Vancouver, BC, Canada. pgershko@interchange.ubc.ca
Wasan
Ellen K
EK
Lin
Molly
M
Sivak
Olena
O
Leon
Carlos G
CG
Clement
John G
JG
Wasan
Kishor M
KM
D000284:Administration, Oral; D000666:Amphotericin B / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000825:Animal Structures / Q000737:chemistry; D000818:Animals; D000935:Antifungal Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D001682:Biological Availability; D002851:Chromatography, High Pressure Liquid; D006207:Half-Life; D008297:Male; D051381:Rats; D013997:Time Factors
D000935:Antifungal Agents; C068538:liposomal amphotericin B; D000666:Amphotericin B