Polyethylene glycol‐based low generation dendrimers functionalized with β‐cyclodextrin as cryo‐ and dehydro‐protectant of catalase formulations |
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| Authors: | Patricio R. Santagapita M. Florencia Mazzobre Ariel García Cruz Horacio R. Corti Reynaldo Villalonga M. Pilar Buera |
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| Affiliation: | 1. Industry Dept. and Organic Chemistry Dept., Faculty of Exact and Natural Sciences, University of Buenos Aires, Intendente Güiraldes 2160 ‐ Ciudad Universitaria—(FCEyN‐UBA) & National Council of Scientific and Technical Research (CONICET), , Argentina;2. Centro de Estudios de Tecnología Enzimática, Facultad de Agronomía, Universidad de Matanzas “Camilo Cienfuegos”, , Matanzas, Cuba;3. Departamento de Física de la Materia Condensada, Comisión Nacional de Energía Atómica, Centro Atómico Constituyentes, Avda. General Paz 1499, , San Martín, 1650 Buenos Aires, Argentina;4. Instituto de Química Física de los Materiales, Ambiente y Energía (INQUIMAE), . Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria., , 1428 Buenos Aires, Argentina;5. Dept. of Analytical Chemistry, Faculty of Chemistry, Complutense University of Madrid, Av. de Séneca 2, 28040, , Madrid, Spain |
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| Abstract: | Polyethylene glycol (PEG)‐based low generation dendrimers are analyzed as single excipient or combined with trehalose in relation to their structure and efficiency as enzyme stabilizers during freeze‐thawing, freeze‐drying, and thermal treatment. A novel functional dendrimer (DGo‐CD) based on the known PEG's ability as cryo‐protector and β‐CD as supramolecular stabilizing agent is presented. During freeze‐thawing, PEG and β‐CD failed to prevent catalase denaturation, while dendrimers, and especially DGo‐CD, offered the better protection to the enzyme. During freeze‐drying, trehalose was the best protective additive but DGo‐CD provided also an adequate catalase stability showing a synergistic behavior in comparison to the activities recovered employing PEG or β‐CD as unique additives. Although all the studied dendrimers improved the enzyme remaining activity during thermal treatment of freeze‐dried formulations, the presence of amorphous trehalose was critical to enhance enzyme stability. The crystallinity of the protective matrix, either of PEG derivatives or of trehalose, negatively affected catalase stability in the freeze‐dried systems. When humidified at 52% of relative humidity, the dendrimers delayed trehalose crystallization in the combined matrices, allowing extending the protection at those conditions in which normally trehalose fails. The results show how a relatively simple covalent combination of a polymer such as PEG with β‐CD could significantly affect the properties of the individual components. Also, the results provide further insights about the role played by polymer–enzyme supramolecular interactions (host–guest crosslink, hydrogen bonding, and hydrophobic interactions) on enzyme stability in dehydrated models, being the effect on the stabilization also influenced by the physical state of the matrix. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:786–795, 2013 |
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| Keywords: | dendrimer enzyme stability β ‐cyclodextrin dehydration freezing and thawing, PEG trehalose catalase |
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