title: 7-Ethyl-10-hydroxycamptothecin proliposomes with a novel preparation method: optimized formulation, characterization and in-vivo evaluation.
abstract: BACKGROUND
  The proliposomes were used to solve the stability of the ordinary liposomes.
  
  
  OBJECTIVE
  7-ethyl-10-hydroxycamptothecin (SN-38) proliposomes for intravenous (i.v.) administration were prepared successfully by a new method.
  
  
  METHODS
  SN-38 liposomes solution was reconstituting automatically from proliposomes on contact with the acetic acid buffer solution (0.2 M, pH 2.6). The formulation was optimized by the Box-Behnken design. The physicochemical characteristics of the SN-38 proliposomes were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The stability studies were also carried on. The FLU-HPLC system was served to study the concentration of SN-38 in the plasma of Sprague Dawley (SD) rats.
  
  
  RESULTS
  The optimized formulation was SN-38: 0.03 g; Soybean phospholipid (SP): 0.6 g; dextrose: 3.00 g. The entrapment efficiency of the optimized formulation was >85% and the mean particle size was about 231 nm. The stability studies showed that SN-38 proliposomes were stable in dark at 20-25°C for 6 months at least. The pharmacokinetic parameters of i.v. administration demonstrated that the half-life of SN-38 loaded in the liposomes was prolonged in vivo.
  
  
  CONCLUSIONS
  The SN-38 proliposomes was prepared successful by the analysis of TEM, SEM, DSC and XRD, and SN-38 liposomes could be reconstituted on contact with the hydration medium. SN-38 liposomes circulated for a longer time in the blood circulating system than SN-38 solution, which contributed to maintaining the drug action.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, PR China. Xiaohu6408_cn@sina.com
authors.forename: Shujun
authors.initials: S
authors.lastname: Wang
authors.forename: Tiantian
authors.initials: T
authors.lastname: Ye
authors.forename: Boyang
authors.initials: B
authors.lastname: Yang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Yi
authors.forename: Huimin
authors.initials: H
authors.lastname: Yao
mesh_terms: D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry* / Q000493:pharmacokinetics; D001672:Biocompatible Materials; D002152:Calorimetry, Differential Scanning; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000493:pharmacokinetics; D004355:Drug Stability; D006207:Half-Life; D008081:Liposomes / Q000737:chemistry* / Q000493:pharmacokinetics; D010316:Particle Size; D051381:Rats; D017207:Rats, Sprague-Dawley; D014961:X-Ray Diffraction
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D001672:Biocompatible Materials; D008081:Liposomes; D002166:Camptothecin