Engineering of a novel adjuvant based on lipid-polymer hybrid nanoparticles: A quality-by-design approach

J Control Release. 2015 Jul 28:210:48-57. doi: 10.1016/j.jconrel.2015.05.004. Epub 2015 May 6.


The purpose of this study was to design a novel and versatile adjuvant intended for mucosal vaccination based on biodegradable poly(DL-lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) modified with the cationic surfactant dimethyldioctadecylammonium (DDA) bromide and the immunopotentiator trehalose-6,6'-dibehenate (TDB) (CAF01) to tailor humoral and cellular immunity characterized by antibodies and Th1/Th17 responses. Such responses are important for the protection against diseases caused by intracellular bacteria such as Chlamydia trachomatis and Mycobacterium tuberculosis. The hybrid NPs were engineered using an oil-in-water single emulsion method and a quality-by-design approach was adopted to define the optimal operating space (OOS). Four critical process parameters (CPPs) were identified, including the acetone concentration in the water phase, the stabilizer [polyvinylalcohol (PVA)] concentration, the lipid-to-total solid ratio, and the total concentration. The CPPs were linked to critical quality attributes consisting of the particle size, polydispersity index (PDI), zeta-potential, thermotropic phase behavior, yield and stability. A central composite face-centered design was performed followed by multiple linear regression analysis. The size, PDI, enthalpy of the phase transition and yield were successfully modeled, whereas the models for the zeta-potential and the stability were poor. Cryo-transmission electron microscopy revealed that the main structural effect on the nanoparticle architecture is caused by the use of PVA, and two different morphologies were identified: i) A PLGA core coated with one or several concentric lipid bilayers, and ii) a PLGA nanoshell encapsulating lipid membrane structures. The optimal formulation, identified from the OOS, was evaluated in vivo. The hybrid NPs induced antibody and Th1/Th17 immune responses that were similar in quality and magnitude to the response induced by DDA/TDB liposomes, showing that the adjuvant properties of DDA/TDB are maintained in the PLGA hybrid matrix. This study demonstrates the complexity of formulation design for the engineering of a hybrid lipid-polymer nanoparticle adjuvant.

Keywords: Adjuvant; Dimethyldioctadecylammonium (DDA); Drug delivery; Nanomedicine; Nanoparticles; PLGA; Quality-by-design (QbD); Trehalose 6,6-dibehenate; Vaccine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adjuvants, Immunologic / chemistry*
  • Drug Design
  • Glycolipids / chemistry*
  • Lactic Acid / chemistry*
  • Microscopy, Electron, Transmission
  • Nanoparticles / chemistry*
  • Nanoparticles / ultrastructure
  • Polyglycolic Acid / chemistry*
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • Quaternary Ammonium Compounds / chemistry
  • Surface-Active Agents / chemistry


  • Adjuvants, Immunologic
  • Glycolipids
  • Quaternary Ammonium Compounds
  • Surface-Active Agents
  • trehalose 6,6'-dibehenate
  • Polylactic Acid-Polyglycolic Acid Copolymer
  • dimethyldioctadecylammonium
  • Polyglycolic Acid
  • Lactic Acid