title: Complex coacervates of hyaluronic acid and lysozyme: effect on protein structure and physical stability.
abstract: Complex coacervates of hyaluronic acid and lysozyme, a model protein, were formed by ionic interaction using bulk mixing and were characterized in terms of binding stoichiometry and protein structure and stability. The complexes were formed at pH 7.2 at low ionic strength (6mM) and the binding stoichiometry was determined using solution depletion and isothermal titration calorimetry. The binding stoichiometry of lysozyme to hyaluronic acid (870 kDa) determined by solution depletion was found to be 225.9 ± 6.6 mol, or 0.1 bound lysozyme molecules per hyaluronic acid monomer. This corresponded well with that obtained by isothermal titration calorimetry of 0.09 bound lysozyme molecules per hyaluronic acid monomer. The complexation did not alter the secondary structure of lysozyme measured by Fourier-transform infrared spectroscopy overlap analysis and had no significant impact on the Tm of lysozyme determined by differential scanning calorimetry. Furthermore, the protein stability of lysozyme was found to be improved upon complexation during a 12-weeks storage study at room temperature, as shown by a significant increase in recovered protein when complexed (94 ± 2% and 102 ± 5% depending on the polymer-protein weight to weight ratio) compared to 89 ± 2% recovery for uncomplexed protein. This study shows the potential of hyaluronic acid to be used in combination with complex coacervation to increase the physical stability of pharmaceutical protein formulations.
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen O, Denmark. Electronic address: jorrit.water@sund.ku.dk.
authors.forename: Jorrit J
authors.initials: JJ
authors.lastname: Water
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen O, Denmark; Novozymes A/S, Biopharma Application Development, Bagsvaerd, Denmark.
authors.forename: Malthe M
authors.initials: MM
authors.lastname: Schack
authors.affiliation: Institute of Biocomputation and Physics of Complex Systems (BIFI), Joint-Unit IQFR-CSIC-BIFI, Department of Biochemistry and Molecular and Cell Biology, University of Zaragoza, Zaragoza, Spain; Fundacion ARAID, Government of Aragon, Zaragoza, Spain.
authors.forename: Adrian
authors.initials: A
authors.lastname: Velazquez-Campoy
authors.affiliation: Novozymes A/S, Biopharma Application Development, Bagsvaerd, Denmark.
authors.forename: Morten J
authors.initials: MJ
authors.lastname: Maltesen
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen O, Denmark.
authors.forename: Marco
authors.initials: M
authors.lastname: van de Weert
authors.affiliation: Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen O, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Jorgensen
mesh_terms: D002152:Calorimetry, Differential Scanning; D006820:Hyaluronic Acid / Q000737:chemistry*; D009113:Muramidase / Q000737:chemistry*; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D006820:Hyaluronic Acid; D009113:Muramidase
keywords: Binding characteristics; Bovine serum albumin; Complex coacervation; Differential scanning calorimetry; Differential scanning fluorimetry; Hyaluronan; Hydrogel; Isothermal titration calorimetry; Sodium hyaluronate; Stability