title: Microencapsulation of hepatitis B core antigen for vaccine preparation.
abstract: OBJECTIVE
  To prepare poly(lactide-co-glycolide)(PLGA) microspheres containing recombinant hepatitis B core antigen (HBcAg; Mw = 3,600,000) by a w/o/w emulsion/solvent evaporation method and evaluate the possibility of this system as a potent long-acting carrier for hepatitis B core antigen in mice.
  
  
  METHODS
  Various additives had been incorporated in the internal aqueous phase during the process of microencapsulating HBcAg, HBcAg antigenicity in the medium extracted from the prepared microspheres were measured by ELISA. Shape confirmation of the HBcAg antigen was performed by a sucrose gradient velocity centrifugal technique. For in vivo study, prepared microspheres were administered subcutaneously to Balb/C mice, and the serum IgG level was determined by ELISA.
  
  
  RESULTS
  The inactivation of HBcAg by methylene chloride was dramatically reduced by the addition of gelatin (4-8% (w/v)) to the internal aqueous phase during the preparation. Further improvement of the loading efficiency to almost 61% resulted with cooling (4 degrees C). The prepared microspheres (4.27 microm+/-1.23 microm) containing 0.15% HBcAg displayed burst release (50-60% within 2 days). In subcutaneous inoculation, the adjuvant effect of PLGA microspheres was almost the same as that of the complete Freund's adjuvant. Whereas oral inoculation using the microspheres was not effective.
  
  
  CONCLUSIONS
  The pH of the added gelatin seemed to be the key to the stabilization of HBcAg from various stability tests and CD spectrum study. Finally, the possibility of using this system as a potent long-acting hepatitis B vaccine was demonstrated.
authors.affiliation: School of Pharmaceutical Sciences, Mukogawa Women's University, Nishinomiya City, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Uchida
authors.forename: K
authors.initials: K
authors.lastname: Shiosaki
authors.forename: Y
authors.initials: Y
authors.lastname: Nakada
authors.forename: K
authors.initials: K
authors.lastname: Fukada
authors.forename: Y
authors.initials: Y
authors.lastname: Eda
authors.forename: S
authors.initials: S
authors.lastname: Tokiyoshi
authors.forename: N
authors.initials: N
authors.lastname: Nagareya
authors.forename: K
authors.initials: K
authors.lastname: Matsuyama
mesh_terms: D000818:Animals; D004339:Drug Compounding; D004355:Drug Stability; D005260:Female; D006512:Hepatitis B Core Antigens / Q000008:administration & dosage*; D017325:Hepatitis B Vaccines / Q000008:administration & dosage*; D051379:Mice; D008807:Mice, Inbred BALB C; D008863:Microspheres; D008970:Molecular Weight
chemical_list: D006512:Hepatitis B Core Antigens; D017325:Hepatitis B Vaccines