Monitoring ibuprofen enantiomers released from polymeric systems.
Two methacrylic derivatives of ibuprofen (N-[4-[2-(4-isobutylphenyl)propionyloxy]phenyl] methacrylamide (MAI) and 2-[(4-isobutylphenyl)propionyloxy]ethyl methacrylate (MEI)) were used together with 2-hydroxyethyl methacrylate (HEMA) to synthesize four polymeric materials: two hydrophobic homopolymers, PMAI and PMEI, and two hydrophilic copolymers containing 70% (w/w) HEMA, MAI-HEMA 30 and MEI-HEMA 30. The enantiomeric determination of R- and S-IBU released from these four systems has been carried out by capillary electrophoresis. Release of R- and S-IBU was monitored during in vitro assays done at 37 degrees C at pH 7.4 and 10 in buffered solutions and rat plasma. There is a hydrolytical activation in plasma and at pH 10 compared to pH 7.4; moreover, the release rate from the copolymers is much higher than from the homopolymers as a consequence of the greater hydrophilic character. A slight excess of the S-enantiomer of IBU is observed in all the experiments, being more relevant at higher release rates, i.e. copolymers at pH 10.
Simó
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Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, 28006, Madrid, Spain.
Gallardo
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Parejo
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San Román
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Barbas
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Cifuentes
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D000818:Animals; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D019075:Electrophoresis, Capillary; D006863:Hydrogen-Ion Concentration; D007052:Ibuprofen / Q000737:chemistry*; D066298:In Vitro Techniques; D008297:Male; D008689:Methacrylates / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D013237:Stereoisomerism; D013997:Time Factors
C472506:2-((4-isobutylphenyl)propionyloxy)ethyl methacrylate; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D008689:Methacrylates; C104743:N-(4-(2-(4-isobutylphenyl)propionyloxy)phenyl)methacrylamide; D011108:Polymers; C005044:hydroxyethyl methacrylate; D007052:Ibuprofen