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Kocherbitov V, Music D, Veryazov V. Hydrogen bonding in glassy trehalose-water system: Insights from density functional theory and molecular dynamics simulations. J Chem Phys 2024; 160:084504. [PMID: 38411233 DOI: 10.1063/5.0194537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 01/30/2024] [Indexed: 02/28/2024] Open
Abstract
We report a detailed density functional theory and molecular dynamics study of hydrogen bonding between trehalose and water, with a special emphasis on interactions in the amorphous solid state. For comparison, water-water interactions in water dimers and tetramers are evaluated using quantum calculations. The results show that the hydrogen bonding energy is dependent not only on the geometry (bond length and angle) but also on the local environment of the hydrogen bond. This is seen in quantum calculations of complexes in vacuum as well as in amorphous solid states with periodic boundary conditions. The temperature-induced glass transition in the trehalose-water system was studied using molecular dynamics simulations with varying cooling and heating rates. The obtained parameters of the glass transition are in good agreement with the experiments. Moreover, the dehydration of trehalose in the glassy state was investigated through a gradual dehydration with multiple small steps under isothermal conditions. From these simulations, the values of water sorption energy at different temperatures were obtained. The partial molar enthalpy of mixing of water value of -18 kJ/mol found in calorimetric experiments was accurately reproduced in these simulations. These findings are discussed in light of the hydrogen bonding data in the system. We conclude that the observed exothermic effect is due to different responses of liquid and glassy matrices to perturbations associated with the addition or removal of water molecules.
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Affiliation(s)
- Vitaly Kocherbitov
- Department of Biomedical Science, Faculty of Health and Society, Malmö University, SE-205 06 Malmö, Sweden
- Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
| | - Denis Music
- Biofilms Research Center for Biointerfaces, Malmö University, SE-205 06 Malmö, Sweden
- Department of Materials Science and Applied Mathematics, Faculty of Technology and Society, Malmö University, SE-205 06 Malmö, Sweden
| | - Valera Veryazov
- Computational Chemistry, Kemicentrum, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
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Bogdanova E, Lages S, Phan-Xuan T, Kamal MA, Terry A, Millqvist Fureby A, Kocherbitov V. Lysozyme-Sucrose Interactions in the Solid State: Glass Transition, Denaturation, and the Effect of Residual Water. Mol Pharm 2023; 20:4664-4675. [PMID: 37555640 PMCID: PMC10481396 DOI: 10.1021/acs.molpharmaceut.3c00403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/10/2023]
Abstract
The freeze-drying of proteins, along with excipients, offers a solution for increasing the shelf-life of protein pharmaceuticals. Using differential scanning calorimetry, thermogravimetric analysis, sorption calorimetry, and synchrotron small-angle X-ray scattering (SAXS), we have characterized the properties at low (re)hydration levels of the protein lysozyme, which was freeze-dried together with the excipient sucrose. We observe that the residual moisture content in these samples increases with the addition of lysozyme. This results from an increase in equilibrium water content with lysozyme concentration at constant water activity. Furthermore, we also observed an increase in the glass transition temperature (Tg) of the mixtures with increasing lysozyme concentration. Analysis of the heat capacity step of the mixtures indicates that lysozyme does not participate in the glass transition of the sucrose matrix; as a result, the observed increase in the Tg of the mixtures is the consequence of the confinement of the amorphous sucrose domains in the interstitial space between the lysozyme molecules. Sorption calorimetry experiments demonstrate that the hydration behavior of this formulation is similar to that of the pure amorphous sucrose, while the presence of lysozyme only shifts the sucrose transitions. SAXS analysis of amorphous lysozyme-sucrose mixtures and unfolding of lysozyme in this environment show that prior to unfolding, the size and shape of lysozyme in a solid sucrose matrix are consistent with its native state in an aqueous solution. The results obtained from our study will provide a better understanding of the low hydration behavior of protein-excipient mixtures and support the improved formulation of biologics.
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Affiliation(s)
- Ekaterina Bogdanova
- Biomedical
Science, Malmö University, Malmo SE-20506, Sweden
- Biofilms
research center for Biointerfaces, Malmo SE-20506, Sweden
| | - Sebastian Lages
- Biomedical
Science, Malmö University, Malmo SE-20506, Sweden
- Biofilms
research center for Biointerfaces, Malmo SE-20506, Sweden
- MAX
IV Laboratory, Lund University, Lund SE-22484, Sweden
| | - Tuan Phan-Xuan
- Biomedical
Science, Malmö University, Malmo SE-20506, Sweden
- Biofilms
research center for Biointerfaces, Malmo SE-20506, Sweden
- MAX
IV Laboratory, Lund University, Lund SE-22484, Sweden
| | - Md. Arif Kamal
- Biomedical
Science, Malmö University, Malmo SE-20506, Sweden
- Biofilms
research center for Biointerfaces, Malmo SE-20506, Sweden
- Division
of Physical Chemistry, Lund University, Box 124, Lund SE-221 00, Sweden
| | - Ann Terry
- MAX
IV Laboratory, Lund University, Lund SE-22484, Sweden
| | | | - Vitaly Kocherbitov
- Biomedical
Science, Malmö University, Malmo SE-20506, Sweden
- Biofilms
research center for Biointerfaces, Malmo SE-20506, Sweden
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Bogdanova E, Fureby AM, Kocherbitov V. Influence of cooling rate on ice crystallization and melting in sucrose-water system. J Pharm Sci 2022; 111:2030-2037. [PMID: 35120964 DOI: 10.1016/j.xphs.2022.01.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 01/26/2022] [Accepted: 01/26/2022] [Indexed: 11/19/2022]
Abstract
The ice crystallization and melting in systems where the equilibrium state is difficult to reach is one of the growing areas in pharmaceutical freeze-drying research. The quality of the final freeze-dried product depends on the parameters of the cooling step, which affect the ice nucleation and growth. In this paper, we present a DSC study of ice crystallization and melting in a sucrose-water system. Using two different types of thermal cycles, we examine the influence of cooling and heating rates on the thermal behavior of sucrose-water solutions with water contents between 50 and 100 wt%. The DSC results show that low cooling rates provide crystallization at higher temperatures and lead to lower amount of nonfreezing water. Consequently, the glass transition and ice melting properties observed upon heating depend on the cooling conditions in the preceding step. Based on the experimental results, we investigate the reasons for the existence of the two steps on DSC heating curves in sucrose-water systems: the glass transition step and the onset of ice melting. We show that diffusion of water can be the limiting factor for ice growth and melting in the sucrose-water system when the amorphous phase is in a liquid state. In particular, when the diffusion coefficient drops below 10-14 m2/sec, the ice crystals growth or melting becomes strongly suppressed even above the glass transition temperature. Understanding the diffusion limitations in the sucrose-water system can be used for the optimization of the freeze-drying protocols for proteins and probiotics.
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Affiliation(s)
- Ekaterina Bogdanova
- Biomedical Science, Malmö University, Malmö, Sweden; Biofilms research center for Biointerfaces, Malmö, Sweden; NextBioForm Competence Centre, Stockholm, Sweden
| | - Anna Millqvist Fureby
- RISE Research Institutes of Sweden, Stockholm, Sweden; NextBioForm Competence Centre, Stockholm, Sweden
| | - Vitaly Kocherbitov
- Biomedical Science, Malmö University, Malmö, Sweden; Biofilms research center for Biointerfaces, Malmö, Sweden; NextBioForm Competence Centre, Stockholm, Sweden.
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