title: [Influence of suspending agents on relative bioavailability of cyclosporine A-loaded HPMCP nanoparticles for oral administration to rats].
abstract: OBJECTIVE
  To study the influence of suspending agents on the relative bioavailability of Cyclosporine A-loaded HPMCP(HP55) nanoparticles for oral administration.
  
  
  METHODS
  Suspending agents such as Vanzan, HPMC, Carbopol were added into cyclosporine A-loaded HP55 nanoparticles. The suspended nanoparticle formulations and Neoral were administered orally in a dosage of 15 mg/kg to rats. The CyA concentrations in the blood sample were determined by HPLC. Pharmacokinetic parameters were calculated by 3P97.
  
  
  RESULTS
  The concentration-time data of these preparations were best fit by two compartment model with a weight of 1/C(2). Compared with the reference Neoral microemulsion, the relative bioavailability of 2 g/L Carbopol, 5 g/L Vanzan, 8, 5, 3 g/L HPMC suspended nanoparticles were 70.2%, 84.3%, 90.0%, 94.5% and 97.7%, respectively. Their viscosity values were 550, 362, 105, 30 and 15 mPaxs, respectively.
  
  
  CONCLUSIONS
  With the increase in viscosity, the relative bioavailability of nanoparticle formulations decreased. So, it is important to select the appropriate viscosity of suspending agents in the formulation design.
authors.affiliation: Department of Pharmaceutics, Peking University School of Pharmaceutical Sciences, Beijing 100083, China.
authors.forename: Xun-qing
authors.initials: XQ
authors.lastname: Wang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.forename: Jun-dong
authors.initials: JD
authors.lastname: Dai
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.forename: Gui-min
authors.initials: GM
authors.lastname: Xia
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D016572:Cyclosporine / Q000008:administration & dosage* / Q000493:pharmacokinetics; D005079:Excipients / Q000494:pharmacology*; D007166:Immunosuppressive Agents / Q000008:administration & dosage*; D008297:Male; D008747:Methylcellulose / Q000008:administration & dosage* / Q000031:analogs & derivatives; D051381:Rats; D017207:Rats, Sprague-Dawley; D014783:Viscosity
chemical_list: D005079:Excipients; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D008747:Methylcellulose; C053309:hydroxypropyl methylcellulose phthalate