title: Proliposomes for oral delivery of dehydrosilymarin: preparation and evaluation in vitro and in vivo.
abstract: OBJECTIVE
  To formulate proliposomes with a polyphase dispersed system composed of soybean phospholipids, cholesterol, isopropyl myristate and sodium cholate to improve the oral bioavailability of dehydrosilymarin, an oxidized form of herbal drug silymarin.
  
  
  METHODS
  Dehydrosilymarin was synthesized from air oxidation of silymarin in the presence of pyridine, and proliposomes were prepared by a film dispersion-freeze drying method. Morphological characterization of proliposomes was observed using a transmission electron microscope. Particle size and encapsulation efficiency of proliposomes were measured. The in vitro release of dehydrosilymarin from suspension and proliposomes was evaluated. The oral bioavailability of dehydrosilymarin suspension and proliposomes was investigated in rabbits.
  
  
  RESULTS
  The proliposomes prepared under the optimum conditions were spherical and smooth with a mean particle size in the range of 7 to 50 nm. Encapsulation efficiency was 81.59%±0.24%. The in vitro accumulative release percent of dehydrosilymarinloaded proliposomes was stable, which was slow in pH 1.2, and increased continuously in pH 6.8, and finally reached 86.41% at 12 h. After oral administration in rabbits, the relative bioavailability of proliposomes versus suspension in rabbits was 228.85%.
  
  
  CONCLUSIONS
  Proliposomes may be a useful vehicle for oral delivery of dehydrosilymarin, a drug poorly soluble in water.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Jiangsu University, Zhenjiang 212013, China.
authors.forename: Chang
authors.initials: C
authors.lastname: Chu
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Tong
authors.forename: Ying
authors.initials: Y
authors.lastname: Xu
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Min
authors.initials: M
authors.lastname: Fu
authors.forename: Yan-ru
authors.initials: YR
authors.lastname: Ge
authors.forename: Jiang-nan
authors.initials: JN
authors.lastname: Yu
authors.forename: Xi-ming
authors.initials: XM
authors.lastname: Xu
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D020944:Silybum marianum / Q000737:chemistry*; D020011:Protective Agents / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000493:pharmacokinetics*; D011817:Rabbits; D012838:Silymarin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000493:pharmacokinetics
chemical_list: D008081:Liposomes; D020011:Protective Agents; D012838:Silymarin; C561900:dehydrosilymarin