title: Controlled release of glaucocalyxin - a self-nanoemulsifying system from osmotic pump tablets with enhanced bioavailability.
abstract: OBJECTIVE
  The purpose of this study was to develop a new formulation to enhance the bioavailability simultaneously with controlled release of glaucocalyxin A (GLA).
  
  
  METHODS
  In this study, controlled release of GLA was achieved by the osmotic release strategy taking advantage of the bioavailability enhancing capacity of self-nanoemulsifying drug delivery systems (SNEDDS). The formulation of GLA-SNEDDS was selected by the solubility and pseudoternary-phase diagrams studies. The prepared GLA-SNEDDS formulations were characterized for self-emulsification time, effect of pH and robustness to dilution, droplet size analysis and zeta potential. The optimized GLA-SNEDDS were used to prepare GLA-SNEDDS osmotic pump tablet via direct powder compression method. The effect of formulation variables on the release characteristic was investigated. GLA-SNEDDS osmotic pump tablets were administered to beagle dogs and their pharmacokinetics were compared to GLA and GLA-SNEDDS as a control.
  
  
  RESULTS
  In vitro drug release studies indicated that the GLA-SNEDDS osmotic pump tablet showed sustained release profiles with 90% released within 12 h. Pharmacokinetic study showed steady blood GLA with prolonged Tmaxand mean residence time (MRT), and enhanced bioavailability for GLA-SNEDDS osmotic pump tablet.
  
  
  CONCLUSIONS
  It was concluded that simultaneous controlling on GLA release and enhanced bioavailability had been achieved by a combination of osmotic pump tablet and SNEDDS.
authors.affiliation: a School of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University , Nanjing , China and.
authors.forename: Miao
authors.initials: M
authors.lastname: Yanfei
authors.affiliation: b School of Pharmaceutical Sciences Nanjing Tech University , Nanjing , China.
authors.forename: Chen
authors.initials: C
authors.lastname: Guoguang
authors.affiliation: b School of Pharmaceutical Sciences Nanjing Tech University , Nanjing , China.
authors.forename: Ren
authors.initials: R
authors.lastname: Lili
authors.affiliation: a School of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University , Nanjing , China and.
authors.forename: Ouyang
authors.initials: O
authors.lastname: Pingkai
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage* / Q000097:blood* / Q000737:chemistry; D001682:Biological Availability; D003692:Delayed-Action Preparations / Q000737:chemistry*; D045786:Diterpenes, Kaurane / Q000008:administration & dosage* / Q000097:blood* / Q000737:chemistry; D004285:Dogs; D004655:Emulsions / Q000737:chemistry; D005079:Excipients / Q000737:chemistry; D009995:Osmosis; D044367:Phase Transition; D012995:Solubility; D013607:Tablets
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D045786:Diterpenes, Kaurane; D004655:Emulsions; D005079:Excipients; D013607:Tablets; C055124:glaucocalyxin A
keywords: Bioavailability; control release; glaucocalyxin A; osmotic pump tablet; self-nanoemulsifying