title: Microneedles with intrinsic immunoadjuvant properties: microfabrication, protein stability, and modulated release.
abstract: OBJECTIVE
  Intradermal immunization using microneedles requires compatible immunoadjuvant system. To address this challenge, we investigated microneedles coated with polyphosphazene polyelectrolyte, which served both as microfabrication material and an immunoadjuvant compound.
  
  
  METHODS
  Coated microneedles were fabricated by depositing formulations containing Poly[di(carboxylatophenoxy)phosphazene], PCPP, on metal shafts, and their physico-chemical characterization was conducted.
  
  
  RESULTS
  Microfabrication of PCPP-coated microneedles exhibited strong dependence on protein-PCPP interactions in solutions and allowed for high efficiency of protein encapsulation. 70°C thermal inactivation studies demonstrated a remarkable increase in functional stability of protein in coated microneedles compared to solution formulation. A potential for modulation of protein release from coated microneedles has been demonstrated through ionic complexation of PCPP with small ions.
  
  
  CONCLUSIONS
  Microneedles containing PCPP coatings provide improved protein stability, modulated release, and protein-friendly microfabrication process.
authors.affiliation: Research & Development, Apogee Technology, Inc., 129 Morgan Drive, Norwood, Massachusetts 02062, USA. aandrianov@apogeebio.com
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Andrianov
authors.forename: Alexander
authors.initials: A
authors.lastname: Marin
authors.forename: Daniel P
authors.initials: DP
authors.lastname: DeCollibus
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D007114:Immunization / Q000295:instrumentation / Q000379:methods; D007271:Injections, Intradermal; D008845:Microinjections / Q000295:instrumentation / Q000379:methods; D009339:Needles; D009943:Organophosphorus Compounds / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D055550:Protein Stability; D012710:Serum Albumin, Bovine / Q000008:administration & dosage; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods*; D013997:Time Factors; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D009943:Organophosphorus Compounds; D011108:Polymers; D014612:Vaccines; C546078:poly(di(carboxylatophenoxy)phosphazene); D012710:Serum Albumin, Bovine