Trehalose Glycopolymer Enhances Both Solution Stability and Pharmacokinetics of a Therapeutic Protein

Abstract

Biocompatible polymers such as poly(ethylene glycol) (PEG) have been successfully conjugated to therapeutic proteins to enhance their pharmacokinetics. However, many of these polymers, including PEG, only improve the in vivo lifetimes and do not protect proteins against inactivation during storage and transportation. Herein, we report a polymer with trehalose side chains (PolyProtek) that is capable of improving both the external stability and the in vivo plasma half-life of a therapeutic protein. Insulin was employed as a model biologic, and high performance liquid chromatography and dynamic light scattering confirmed that addition of trehalose glycopolymer as an excipient or covalent conjugation prevented thermal or agitation-induced aggregation of insulin. The insulin-trehalose glycopolymer conjugate also showed significantly prolonged plasma circulation time in mice, similar to the analogous insulin-PEG conjugate. The insulin-trehalose glycopolymer conjugate was active as tested by insulin tolerance tests in mice and retained bioactivity even after exposure to high temperatures. The trehalose glycopolymer was shown to be non-toxic to mice up to at least 1.6 mg/kg dosage. These results together suggest that the trehalose glycopolymer should be further explored as an alternative to PEG for long circulating protein therapeutics.

Synthesis and Biological Evaluation of a Degradable Trehalose Glycopolymer Prepared by RAFT Polymerization

“…Therefore, a system of postpolymerization modification was employed. First, RAFT polymerization was performed with a trithiocarbonate chain transfer agent (CTA), but‐3‐enyl methacrylate (bMA), BMDO, and azobisisobutyronitrile (AIBN) to yield p(BMDO‐ co ‐bMA) (see Scheme for synthetic steps and Figure S2 in the Supporting Information for 1 H NMR characterization). The final polymer contained 29 bMA units and 5 BMDO units, with a number‐average molecular weight ( M n ) of 5200 by 1 H NMR and 2900 by gel permeation chromatography (GPC) and a molecular weight dispersity ( Đ ) of 1.76.…”

“…Additionally, synthetic carboxylated polyamidosaccharides have been shown to retain lysozyme activity after multiple lyophilization cycles . And our group has previously reported on glycopolymers with trehalose side chains for enhancing stability of a wide range of proteins against lyophilization, mechanical, and heat stress . Yet, most of the reported stabilizers are not degradable.…”

Fabrication of Polymer–Protein Hybrids

“…Polymer chains bearing functional groups, including activated esters (N‐hydroxysuccinimide (NHS), pentafluorophenyl, thiazolidine‐2‐thione), aldehydes, aminooxy, can react efficiently with the amine groups on proteins. Lutz and co‐workers prepared thermoresponsive oligo(ethylene glycol)‐based copolymers with NHS functional terminal groups by ATRP, and conjugated the polymer chain onto trypsin .…”

Insights on the Structure, Molecular Weight and Activity of an Antibacterial Protein–Polymer Hybrid

“…Protein–polymer hybrid molecules are inspiring biomaterials because they retain the functions/properties of both protein and polymeric materials . For example, upon attachment of neutral polymers, the host protein often shows enhanced stability in the biological environment . This is especially useful for protein delivery wherein the protein often experiences varied (and often harsh) biochemical environments .…”

“…[1][2][3][4][5][6] For example, upon attachmento f neutralp olymers, the host protein often shows enhanced stability in the biological environment. [7][8][9][10] This is especially useful for protein delivery wherein the protein often experiences varied (and often harsh) biochemical environments. [11][12][13][14][15] When placing a" smart" polymer close to the actives ite of ap rotein, it becomes possible to control protein functionv ia controlling the polymer function.…”