Physico-chemical analysis of metronidazole encapsulation processes in Eudragit copolymers and their blending with amphiphilic block copolymers.
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.
de Oliveira
H P
HP
Colegiado de Pós-Graduação em Ciência dos Materiais, Universidade Federal do Vale do São Francisco, 48902-300 Juazeiro, BA, Brazil. helinando.oliveira@univasf.edu.br
Tavares
G F
GF
Nogueiras
C
C
Rieumont
J
J
D002626:Chemistry, Pharmaceutical / Q000379:methods; D004337:Drug Carriers; D008795:Metronidazole / Q000737:chemistry*; D010316:Particle Size; D011092:Polyethylene Glycols; D011108:Polymers; D011109:Polymethacrylic Acids / Q000737:chemistry*; D012995:Solubility; D013501:Surface-Active Agents / Q000737:chemistry
D004337:Drug Carriers; D011108:Polymers; D011109:Polymethacrylic Acids; D013501:Surface-Active Agents; D008795:Metronidazole; C038300:methylmethacrylate-methacrylic acid copolymer; D011092:Polyethylene Glycols