title: Optimizing manufacturing and composition of a TLR4 nanosuspension: physicochemical stability and vaccine adjuvant activity.
abstract: BACKGROUND
  Nanosuspensions are an important class of delivery system for vaccine adjuvants and drugs. Previously, we developed a nanosuspension consisting of the synthetic TLR4 ligand glucopyranosyl lipid adjuvant (GLA) and dipalmitoyl phosphatidylcholine (DPPC). This nanosuspension is a clinical vaccine adjuvant known as GLA-AF. We examined the effects of DPPC supplier, buffer composition, and manufacturing process on GLA-AF physicochemical and biological activity characteristics.
  
  
  RESULTS
  DPPC from different suppliers had minimal influence on physicochemical and biological effects. In general, buffered compositions resulted in less particle size stability compared to unbuffered GLA-AF. Microfluidization resulted in rapid particle size reduction after only a few passes, and 20,000 or 30,000 psi processing pressures were more effective at reducing particle size and recovering the active component than 10,000 psi. Sonicated and microfluidized batches maintained good particle size and chemical stability over 6 months, without significantly altering in vitro or in vivo bioactivity of GLA-AF when combined with a recombinant malaria vaccine antigen.
  
  
  CONCLUSIONS
  Microfluidization, compared to water bath sonication, may be an effective manufacturing process to improve the scalability and reproducibility of GLA-AF as it advances further in the clinical development pathway. Various sources of DPPC are suitable to manufacture GLA-AF, but buffered compositions of GLA-AF do not appear to offer stability advantages over the unbuffered composition.
authors.forename: H W Millie
authors.initials: HW
authors.lastname: Fung
authors.forename: Traci J T
authors.initials: TJ
authors.lastname: Mikasa
authors.forename: Julie
authors.initials: J
authors.lastname: Vergara
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: Sivananthan
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Guderian
authors.forename: Malcolm S
authors.initials: MS
authors.lastname: Duthie
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Vedvick
authors.affiliation: IDRI, 1616 Eastlake Ave E, Ste 400, Seattle, WA 98102, USA. cfox@idri.org.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Fox
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000276:Adjuvants, Immunologic / Q000737:chemistry* / Q000494:pharmacology / Q000592:standards; D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D002021:Buffers; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D004355:Drug Stability; D005260:Female; D008050:Lipid A / Q000031:analogs & derivatives / Q000737:chemistry / Q000276:immunology; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008288:Malaria / Q000276:immunology / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000008:administration & dosage / Q000096:biosynthesis / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D049329:Nanostructures / Q000737:chemistry* / Q000592:standards; D010316:Particle Size; D010962:Plasmodium berghei / Q000276:immunology; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D013010:Sonication; D013535:Suspensions; D051197:Toll-Like Receptor 4 / Q000276:immunology
chemical_list: D000276:Adjuvants, Immunologic; D000953:Antigens, Protozoan; D002021:Buffers; D016207:Cytokines; D008050:Lipid A; D017780:Malaria Vaccines; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D013535:Suspensions; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C041595:circumsporozoite protein, Protozoan; D015060:1,2-Dipalmitoylphosphatidylcholine; C048436:monophosphoryl lipid A