title: Oral bioavailability enhancement of a hydrophilic drug delivered via folic acid-coupled liposomes in rats.
abstract: OBJECTIVE
  A liposome preparation that is amenable to receptor-mediated endocytosis has been developed to enhance the oral bioavailability of poorly absorbable peptidomimetic drugs by use of folic acid as the mediator of liposomal uptake.
  
  
  METHODS
  Folic acid was physically coupled to the surface of the liposomes and cefotaxime was used as the model drug. In-vivo evaluation was carried out on eight Sprague-Dawley rats in a two-way crossover study to compare the oral bioavailability of cefotaxime loaded in folic acid-free liposomes and folic acid-coupled liposomes. Blood samples were collected from the tail vein and plasma cefotaxime levels were determined using an HPLC method.
  
  
  RESULTS
  Enhanced oral bioavailability (AUC(0-infinity)) of cefotaxime was observed when administered via folic acid-coupled liposomes. The peak plasma concentration (C(max)) of cefotaxime was increased when administered via folic acid-coupled liposomes as compared with folic acid-free liposomes. At 90% confidence interval, the value for AUC(0-infinity) was 1.4-2-times higher and the value for C(max) was 1.2-1.8-times higher for the folic acid-coupled liposomes compared with folic acid-free liposomes.
  
  
  CONCLUSIONS
  Folic acid could enhance the uptake of liposomally entrapped drug. It could be a useful candidate to supplement liposome delivery systems.
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Penang, Malaysia.
authors.forename: Sharon Sheue Nee
authors.initials: SS
authors.lastname: Ling
authors.forename: Kah Hay
authors.initials: KH
authors.lastname: Yuen
authors.forename: Enrico
authors.initials: E
authors.lastname: Magosso
authors.forename: Susan Anne
authors.initials: SA
authors.lastname: Barker
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D002439:Cefotaxime / Q000008:administration & dosage* / Q000493:pharmacokinetics; D018592:Cross-Over Studies; D016503:Drug Delivery Systems; D004705:Endocytosis / Q000187:drug effects*; D005492:Folic Acid / Q000008:administration & dosage / Q000737:chemistry; D008081:Liposomes; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D008081:Liposomes; D005492:Folic Acid; D002439:Cefotaxime