title: Structure/function relationships of several biopolymers as related to invertase stability in dehydrated systems.
abstract: Structure/function relationships of different biopolymers (alginate, dextran, or beta-cyclodextrin) were analyzed as single excipients or combined with trehalose in relation to their efficiency as enzyme stabilizers in freeze-dried formulations and compared to trehalose. Particularly, a novel synthesized polymer beta-cyclodextrin-branched alginate (beta-CD-A) was employed as excipient. During freeze-drying, the polymers or their mixtures did not confer better protection to invertase compared to trehalose. Beta-CD-A (with or without trehalose), beta-cyclodextrin (beta-CD), or dextran with trehalose were the best protective agents during thermal treatment, while beta-CD and alginate showed a negative effect on invertase activity preservation. The beta-CD linked alginate combined the physical stability provided by alginate with the stabilization of hydrophobic regions of the enzyme provided by cyclodextrin. Beta-CD-A was effective even at conditions at which trehalose lost its protective effect. A relatively simple covalent combination of two biopolymers significantly affected their functionalities and, consequently, their interactions with proteins, modifying enzyme stability patterns.
authors.affiliation: Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria 1428, Buenos Aires, Argentina.
authors.forename: Patricio R
authors.initials: PR
authors.lastname: Santagapita
authors.forename: Leissy Gómez
authors.initials: LG
authors.lastname: Brizuela
authors.forename: M Florencia
authors.initials: MF
authors.lastname: Mazzobre
authors.forename: Héctor L
authors.initials: HL
authors.lastname: Ramirez
authors.forename: Horacio R
authors.initials: HR
authors.lastname: Corti
authors.forename: Reynaldo Villalonga
authors.initials: RV
authors.lastname: Santana
authors.forename: M Pilar
authors.initials: MP
authors.lastname: Buera
mesh_terms: D003890:Desiccation / Q000379:methods*; D004355:Drug Stability; D004795:Enzyme Stability; D005612:Freeze Drying / Q000379:methods; D007795:Laminaria / Q000302:isolation & purification; D011108:Polymers / Q000032:analysis / Q000737:chemistry*; D013329:Structure-Activity Relationship; D043324:beta-Fructofuranosidase / Q000032:analysis / Q000737:chemistry*
chemical_list: D011108:Polymers; D043324:beta-Fructofuranosidase