Influence of the Lipophilic External Phase Composition on the Preparation and Characterization of Xylan Microcapsules—A Technical Note

Autor: Acarília Eduardo da Silva, E. Socrates T. Egito, Luiz Alberto Lira Soares, Toshiyuki Nagashima, Larissa Muratori Aguiar, Henrique Rodrigues Marcelino, Ivonete B. Araújo, Anselmo Gomes de Oliveira, Elquio Eleamen Oliveira, Monique Christine Salgado Gomes
Rok vydání: 2008
Předmět:
Zdroj: AAPS PharmSciTech. 9:814-817
ISSN: 1530-9932
DOI: 10.1208/s12249-008-9115-z
Popis: Scientific studies on new drug delivery systems have significantly increased in the past few years and this growth is expected to continue in the near future (1). Such systems are of great interest because of their ability to improve drug performance in terms of efficacy, safety, and patient compliance (1). In many cases, conventional drug delivery provides an increase of drug concentration at potentially toxic levels (2). Additionally, the need for delivering drugs with fewer side effects has prompted the development of new drug delivery systems (1). Xylan is the second most abundant polymer found in hardwoods and annual plants (3), particularly in agricultural residues such as grain hulls, corn cobs, and corn stalks (4). Depending on the botanical source, the backbone chemical structure may vary. However, the majority of xylans present side chains of different sugars such as 4-O-methyl-d-glucoronic acid, O-acetyl-l-arabinose, l-arabinose, and d-glucoronic acid bond by a glycosidic linkage to the backbone (3). Because of its complex structure, the complete degradation of xylan requires the activity of several enzymes which are specifically produced by human colonic microflora (5). Therefore, xylan microcapsules may represent a novel and promising colon-specific drug delivery system. Microcapsules based on natural polymers may be produced by means of a variety of methods. Emulsion solvent extraction, emulsion solvent evaporation and interfacial cross-linking polymerization are the most commonly employed processes for the production of microcapsules (4). One of the critical parameters in the microencapsulation process is the external phase used in the emulsification step (6). In fact, the external phase can influence the microcapsules morphology, their aggregation state, and mainly the release of the microencapsulated active compound (7). Because the production of xylan-based microcapsules is a subject barely studied by scientists worldwide, the aim of this work was to evaluate the influence of the lipophilic external phase composition on the production and mean particle size of xylan microcapsules produced by interfacial cross-linking polymerization.
Databáze: OpenAIRE
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