title: Bioavailability improvement of mycophenolic acid through amino ester derivatization.
abstract: The potential bioavailability improvement of mycophenolic acid (MPA), 1, through ester derivatization was evaluated in monkeys at a dose of 20 mg/kg in this study. The acetyl solketal ester 3 was found to have excellent partition properties but poor aqueous solubility. Thus, even though it can be converted rapidly to MPA by plasma and liver enzymes, it showed poor oral bioavailability (56% of MPA) in monkeys. The bioavailability of the morpholinoethyl ester 4 and the acetyl morpholinoethyl ester 5, on the other hand, was found to be 236 and 150% that of MPA, respectively. Since ester 5 has greater aqueous solubility, but similar chemical stability and enzymatic hydrolysis rates compared to ester 4, the better bioavailability of ester 4 may result from its greater partitioning into the gastrointestinal membranes.
authors.affiliation: Institute of Pharmaceutical Sciences, Syntex Research, Palo Alto, California.
authors.forename: W A
authors.initials: WA
authors.lastname: Lee
authors.forename: L
authors.initials: L
authors.lastname: Gu
authors.forename: A R
authors.initials: AR
authors.lastname: Miksztal
authors.forename: N
authors.initials: N
authors.lastname: Chu
authors.forename: K
authors.initials: K
authors.lastname: Leung
authors.forename: P H
authors.initials: PH
authors.lastname: Nelson
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism; D008252:Macaca fascicularis; D051379:Mice; D009173:Mycophenolic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000493:pharmacokinetics*; D012995:Solubility; D013045:Species Specificity
chemical_list: D009173:Mycophenolic Acid