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Title: Drug release mechanisms of chemically cross-linked albumin microparticles: effect of the matrix erosion
Authors: Sitta, Danielly L. A. 
Guilherme, Marcos R. 
Silva, Elisangela P. da 
Valente, Artur J. M. 
Muniz, Edvani C. 
Rubira, Adley F. 
Keywords: Albumin; Drug delivery; Emulsion; Erosion; Microparticles; Drug release kinetics
Issue Date: 1-Oct-2014
Publisher: Elsevier
Citation: SITTA, Danielly L. A. [et. al] - Drug release mechanisms of chemically cross-linked albumin microparticles: effect of the matrix erosion. "Colloids and Surfaces B: Biointerfaces". ISSN 0927-7765. Vol. 122 (2014) p. 404–413
Serial title, monograph or event: Colloids and Surfaces B: Biointerfaces
Volume: 122
Abstract: Albumin (BSA) microparticles were developed as a biotechnological alternative for drug delivery. Vitamin B12 (Vit-B12) was used as a model drug. The microparticles were obtained from maleic anhydride-functionalized BSA and N′,N′-dimethylacrylamide (DMAAm) in a W/O emulsion without and with PVA. The microparticles produced at 15 min of stirring without PVA showed the best results in terms of size, homogeneity, and sphericity. In such a case, BSA played a role as a surface active agent, replacing PVA. For longer stirring times, BSA was unable to act as an emulsifier. These microparticles showed an uncommon release profile, consisting of a two-step release mechanism, at the pH range studied. Considering that a two-step release mechanism is occurring, the experimental data were adjusted by applying modified power law and Weibull equations in order to describe release mechanism n and release rate constant k, respectively. Each one of the release stages was related to a specific value of n and k. The second stage was driven by a super case II transport mechanism, as a result of diffusion, macromolecular relaxation, and erosion. A third model, described by Hixson–Crowell, confirmed the erosion mechanism. Vit-B12 diffusion kinetics in aqueous solutions (i.e., without the microparticles) follows a one-step process, being k dependent on the pH, confirming that the two-step release mechanism is a characteristic profile of the developed microparticles. The microparticles released only 2.70% of their initial drug load at pH 2, and 58.53% at pH 10.
ISSN: 0927-7765
DOI: 10.1016/j.colsurfb.2014.07.014
Rights: openAccess
Appears in Collections:FCTUC Química - Artigos em Revistas Internacionais

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