Development of multi-phase emulsions based on bioresorbable polymers and oily adjuvant.
OBJECTIVE
To enhance the water affinity of W/O emulsion-adjuvanted vaccines, we used three bioresorbable polymers named PEG-b-PLA, PEG-b-PCL, and PEG-b-PLACL as hydrophilic emulsifier to stabilize the interfaces between the oily Montanide ISA 51 adjuvant and the antigen media.


METHODS
Polymers were synthesized by ring-opening polymerization of lactide and/or epsilon-caprolactone in the presence of monomethoxy PEG. (1)H NMR and GPC data showed that obtained polymers consisted of 70 wt.% hydrophilic PEG block and 30 wt.% lipophilic PLA, PCL, PLACL block with molecular weights of 7,000.


RESULTS
The polymer-stabilized ISA51 emulsions have high affinity to water, such that the stock of antigen-encapsulating emulsion could be re-dispersed into PBS before injection, thus yielding stable and injectable W/O/W emulsion nanoparticles. Immunogenicity studies showed that PEG-b-PLACL/ISA51/PBS-formulated ovalbumin with only 5% of ISA51 oily adjuvant could induce the same level of antibody titers as those induced by PBS/ISA51-formulated ovalbumin.


CONCLUSIONS
The novel multi-phase emulsions increase fluidity and conceptually diminish local reactions with respect to the W/O type vaccines produced from the same oil. These features are of great interest for applications in candidate vaccine delivery, especially for further optimization of alternative immunization routes, such as intramuscular, transdermal or mucosal administration.
Vaccine Research and Development Center, National Health Research Institutes, 35 Keyan Road, Zhunan, Miaoli, 35053, Taiwan. huangminghsi@nhri.org.tw
Ming-Hsi
MH
Huang
Chiung-Yi
CY
Huang
Shu-Pei
SP
Lien
Syuan-Yi
SY
Siao
Ai-Hsiang
AH
Chou
Hsin-Wei
HW
Chen
Shih-Jen
SJ
Liu
Chih-Hsiang
CH
Leng
Pele
P
Chong
D000276:Adjuvants, Immunologic; D000818:Animals; D002850:Chromatography, Gel; D004655:Emulsions; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers / Q000737:chemistry*
D000276:Adjuvants, Immunologic; D004655:Emulsions; D011108:Polymers