title: Advances in PEGylation of important biotech molecules: delivery aspects.
abstract: BACKGROUND
  Although various injected peptide and protein therapeutics have been developed successfully over the past 25 years, several pharmacokinetic and immunological challenges are still encountered that can limit the efficacy of both novel and established biotech molecules.
  
  
  OBJECTIVE
  PEGylation is a popular technique to address such properties. PEGylated drugs exhibit prolonged half-life, higher stability, water solubility, lower immunogenicity and antigenicity, as well as potential for specific cell targeting. Although PEGylated drug conjugates have been on the market for many years, the technology has steadily developed in respect of site-specific chemistry, chain length, molecular weights and purity of conjugate. These developments have occurred in parallel to improvements in physicochemical methods of characterization.
  
  
  CONCLUSIONS
  This review will discuss recent achievements in PEGylation processes with an emphasis on novel PEG-drugs constructs, the unrealized potential of PEGylation for non-injected routes of delivery, and also on PEGylated versions of polymeric nanoparticles, including dendrimers and liposomes.
authors.affiliation: University College Dublin, School of Agriculture, Food Science and Veterinary Medicine, Veterinary Sciences Building, Room 214, Belfield, Dublin 4, Ireland.
authors.forename: Sinéad M
authors.initials: SM
authors.lastname: Ryan
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mantovani
authors.forename: Xuexuan
authors.initials: X
authors.lastname: Wang
authors.forename: David M
authors.initials: DM
authors.lastname: Haddleton
authors.forename: David J
authors.initials: DJ
authors.lastname: Brayden
mesh_terms: D001709:Biotechnology / Q000379:methods; D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D016503:Drug Delivery Systems; D004355:Drug Stability; D006207:Half-Life; D006801:Humans; D010455:Peptides / Q000008:administration & dosage / Q000493:pharmacokinetics; D011092:Polyethylene Glycols / Q000737:chemistry*; D011506:Proteins / Q000008:administration & dosage / Q000493:pharmacokinetics; D012995:Solubility
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D010455:Peptides; D011506:Proteins; D011092:Polyethylene Glycols