title: Pharmacokinetic advantages of a newly developed tacrolimus oil-in-water-type emulsion via the enteral route.
abstract: We developed an oleic acid oil-in-water (o/w)-type emulsion of a new tacrolimus formulation that presented an improvement in the delivery of the drug for oral absorption. This investigation was undertaken to assess a sustained release drug delivery system and selective drug transfer into the lymphatic system. The whole blood concentration profiles after oral administration at a dose of 2 mg/kg and bone marrow, spleen, liver, lung, small intestine, kidney, brain, and whole blood distribution after oral administration at a dose of 1 mg/kg of o/w emulsion formulation of tacrolimus (O/W group) were compared with those of commercially available formulation (T group) in the rat. The mean diameter of the o/w emulsion droplets was 0.47 microm immediately after preparation. The tacrolimus entrapping efficiency of o/w emulsion was 71.3+/-5.0% in 12 h and did not change for 2 d. The area under the whole blood concentration-time curve (AUC) in the O/W group was significantly higher (P<0.01) than that in the T group. In contrast, the values of constant elimination rate and total clearance in the O/W group were significantly lower (P<0.01) than those in the T group, with a comparative bioavailability of 115.9%. The tissue concentration of tacrolimus in the O/W group was significantly higher levels in the bone marrow, spleen, liver, lung, and small intestine, and significantly lower in the brain and kidney, relative to the T group. The o/w emulsion of tacrolimus may be an improved dosage form via the enteral route.
authors.affiliation: The First Department of Surgery, Hamamatsu University School of Medicine, Shizuoka, Japan. unotake@hama-med.ac.jp
authors.forename: T
authors.initials: T
authors.lastname: Uno
authors.forename: T
authors.initials: T
authors.lastname: Kazui
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: H
authors.initials: H
authors.lastname: Hashimoto
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: B A
authors.initials: BA
authors.lastname: Muhammad
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001921:Brain / Q000378:metabolism; D004655:Emulsions / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics*; D007668:Kidney / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D019301:Oleic Acid / Q000737:chemistry; D051381:Rats; D011919:Rats, Inbred Strains; D013154:Spleen / Q000378:metabolism; D016559:Tacrolimus / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D014867:Water
chemical_list: D004655:Emulsions; D014867:Water; D019301:Oleic Acid; D016559:Tacrolimus