title: Formulation of a microparticle carrier for oral polyplex-based DNA vaccines.
abstract: Oral induction of a disseminated mucosal immune response with polyplex-based DNA vaccines requires the delivery of intact polyplexes (polyelectrolyte complexes formed by self-assembly of plasmid DNA with a cationic polymer) to subepithelial lymphoid tissue (e.g. Peyer's patches) within the gastrointestinal tract. This work describes the formulation of a microparticle polyplex carrier allowing the potential of this approach to be realised. PEGylated PEI/DNA polyplexes (DNA concentration 20 microg/ml) formed at N/P 5:0 (defined as the ratio of polycation amino groups to DNA phosphates) were stable to salt-induced aggregation and could be concentrated to a final DNA concentration of 1 mg/ml without polyplex size increase. Polyplexes containing 1:1 polyethylene glycol (PEG)/polyethylenimine (PEI) ratio (mass/mass) gave similar levels of luciferase gene expression in B16F10 cells compared to non-PEG complexes. Poly-(D,L-lactide-co-glycolide) (PLGA) microparticles containing PEGylated polyplexes (approximately 17% DNA encapsulation efficiency) were formulated using a modified double emulsion solvent evaporation method. The microencapsulation and release of intact polyplexes from the microparticle carrier was demonstrated using polyanion (heparin sulfate and poly(aspartic acid) (PAA)) displacement techniques and electron microscopy. Microparticles containing PEGylated polyplexes (24 microg beta-galactosidase DNA) were given orally to Wistar rats. Significant transgene expression (compared to background) was found in peripheral tissue (spleen) 72 h after administration. This work demonstrates the potential application of microparticle carriers for mucosal polyplex-based vaccination.
authors.affiliation: Centre for Drug Delivery Research, School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Howard
authors.forename: Xiong Wei
authors.initials: XW
authors.lastname: Li
authors.forename: Satyanarayana
authors.initials: S
authors.lastname: Somavarapu
authors.forename: Jasvinder
authors.initials: J
authors.lastname: Singh
authors.forename: Nicky
authors.initials: N
authors.lastname: Green
authors.forename: Kwame N
authors.initials: KN
authors.lastname: Atuah
authors.forename: Yildiz
authors.initials: Y
authors.lastname: Ozsoy
authors.forename: Leonard W
authors.initials: LW
authors.lastname: Seymour
authors.forename: H Oya
authors.initials: HO
authors.lastname: Alpar
mesh_terms: D000284:Administration, Oral; D000818:Animals; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004337:Drug Carriers / Q000737:chemistry / Q000378:metabolism*; D016503:Drug Delivery Systems; D005786:Gene Expression Regulation; D007107:Immune System / Q000502:physiology*; D019344:Lactic Acid / Q000737:chemistry / Q000378:metabolism; D010316:Particle Size; D011092:Polyethylene Glycols / Q000737:chemistry / Q000378:metabolism; D011094:Polyethyleneimine / Q000737:chemistry / Q000378:metabolism; D011100:Polyglycolic Acid / Q000737:chemistry / Q000378:metabolism; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D019444:Vaccines, DNA / Q000008:administration & dosage* / Q000276:immunology
chemical_list: D004337:Drug Carriers; D011108:Polymers; D019444:Vaccines, DNA; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D004247:DNA