title: Inhalable dry powder formulations of siRNA and pH-responsive peptides with antiviral activity against H1N1 influenza virus.
abstract: Pulmonary delivery of siRNA has considerable therapeutic potential for treating viral respiratory infectious diseases including influenza. By introducing siRNA that targets the conserved region of viral genes encoding nucleocapsid protein (NP), viral mRNAs can be degraded and viral replication can be inhibited in mammalian cells. To enable siRNA to be used as an antiviral agent, the nucleic acid delivery barrier must be overcome. Effective local delivery of siRNA to lung tissues is required to reduce the therapeutic dose and minimize systemic adverse effects. To develop a formulation suited for clinical application, complexes of pH-responsive peptides, containing either histidine or 2,3-diaminopropionic acid (Dap), and siRNA were prepared into dry powders by spray drying with mannitol, which was used as a bulking agent. The spray-dried (SD) powders were characterized and found to be suitable for inhalation with good stability, preserving the integrity of the siRNA as well as the biological and antiviral activities. The formulations mediated highly effective in vitro delivery of antiviral siRNA into mammalian lung epithelial cells, leading to significant inhibition of viral replication when the transfected cells were subsequently challenged with H1N1 influenza virus. SD siRNA powders containing pH-responsive peptides are a promising inhalable formulation to deliver antiviral siRNA against influenza and are readily adapted for the treatment of other respiratory diseases.
authors.affiliation: Department of Pharmacology & Pharmacy, ‡School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong , 21 Sassoon Road, Pokfulam, Hong Kong.
authors.forename: Wanling
authors.initials: W
authors.lastname: Liang
authors.forename: Michael Y T
authors.initials: MY
authors.lastname: Chow
authors.forename: Pui Ngan
authors.initials: PN
authors.lastname: Lau
authors.forename: Qi Tony
authors.initials: QT
authors.lastname: Zhou
authors.forename: Philip C L
authors.initials: PC
authors.lastname: Kwok
authors.forename: George P H
authors.initials: GP
authors.lastname: Leung
authors.forename: A James
authors.initials: AJ
authors.lastname: Mason
authors.forename: Hak-Kim
authors.initials: HK
authors.lastname: Chan
authors.forename: Leo L M
authors.initials: LL
authors.lastname: Poon
authors.forename: Jenny K W
authors.initials: JK
authors.lastname: Lam
mesh_terms: D000280:Administration, Inhalation; D000595:Amino Acid Sequence; D023181:Antimicrobial Cationic Peptides / Q000008:administration & dosage / Q000737:chemistry; D000998:Antiviral Agents / Q000008:administration & dosage*; D001483:Base Sequence; D001702:Biopharmaceutics; D002460:Cell Line; D002626:Chemistry, Pharmaceutical; D016503:Drug Delivery Systems; D058995:Dry Powder Inhalers; D020868:Gene Silencing; D006801:Humans; D006863:Hydrogen-Ion Concentration; D053118:Influenza A Virus, H1N1 Subtype / Q000187:drug effects* / Q000235:genetics*; D007251:Influenza, Human / Q000628:therapy; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010316:Particle Size; D010455:Peptides / Q000008:administration & dosage / Q000737:chemistry; D011208:Powders; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000235:genetics
chemical_list: D023181:Antimicrobial Cationic Peptides; D000998:Antiviral Agents; C122154:LAH(4) protein, synthetic; D010455:Peptides; D011208:Powders; D034741:RNA, Small Interfering
keywords: RNA interference; influenza; pH-responsive peptide; pulmonary delivery; small interfering RNA; spray drying