title: [In vitro and in vivo stability of 9-nitrocamptothecin lactone form in rats].
abstract: OBJECTIVE
  To investigate the in vitro and in vivo stability of 9-nitrocamptothecin lactone form in rat plasma.
  
  
  METHODS
  The specific and accurate HPLC method was developed for quantifying 9-nitrocamptothecin lactone form and the total lactone and carboxylate forms simultaneously. By using of this method, the ratios of lactone form to the total in rat plasma at different time were determined in vitro and in vivo. The results were compared to determine which was the main factor influencing the stability of 9-nitrocamptothecin lactone form in rat plasma in vivo.
  
  
  RESULTS
  The stability of lactone form in rat plasma was much higher in vivo than that in vitro.
  
  
  CONCLUSIONS
  Blood cells help to increase the stability of 9-nitrocamptothecin lactone form. Clearance from blood in vivo is the primary factor which influences the plasma stability of 9-nitrocamptothecin lactone form. The kinetic process of 9-nitrocamptothecin lactone form and total drug in rats were both best fitted to a two-compartment model. However, the process of 9-nitrocamptothecin carboxylate form in vivo was best fitted to a one-compartment model.
authors.affiliation: Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Qi-Neng
authors.initials: QN
authors.lastname: Ping
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Guo
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Xiao-Zhu
authors.initials: XZ
authors.lastname: Chu
authors.forename: Ming-Mei
authors.initials: MM
authors.lastname: Song
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D002264:Carboxylic Acids / Q000097:blood / Q000493:pharmacokinetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004355:Drug Stability; D007783:Lactones / Q000097:blood / Q000493:pharmacokinetics*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000970:Antineoplastic Agents; D002264:Carboxylic Acids; D007783:Lactones; C079905:rubitecan; D002166:Camptothecin