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Updated: Jun 21, 2026

Anionic Polymerization of an Amphiphilic Copolymer for Preparation of Block Copolymer Micelles Stabilized by π-π Stacking Interactions
Published on: October 10, 2016
Physico-chemical analysis of metronidazole encapsulation processes in Eudragit copolymers and their blending with
H P de Oliveira1, G F Tavares, C Nogueiras
1Colegiado de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA, Brazil. helinando.oliveira@univasf.edu.br
Abstract:
A physico-chemical analysis of metronidazole-Eudragit copolymers L100 and RLPO (a cationic polymeric matrix with an electrophilic character) was carried out in order to explore the drug-polymer interaction and its possible effects on the encapsulation and release profiles. An oil-in-oil encapsulation procedure was designed to obtain more intimate drug-matrix mixtures and to obtain a better insight into the details of the interaction. The encapsulation efficiency obtained in these cases was high (in the range of 85-95%), but the release rates were quite rapid. Solubility and interaction between metronidazole and copolymers are discussed in detail with a view to explaining the results. Amphiphilic block copolymers of poly(ethylene)-b-(polyethylene oxide) (20, 50 and 80% PEO) were tested as a matrix for metronidazole release in order to improve drug profiles. The performance of RLPO as the matrix for drug release was improved by blending it with amphiphilic block copolymer poly(ethylene)-b-(polyethylene oxide) (20% PEO). The release mechanism of metronidazole is governed mainly by the swelling of RLPO, yielding a better fit with the second-order Schott equation.
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