Regulation of controlled release of ibuprofen from crosslinked polymers containing cubane as a new crosslinking agent

The nonsteroidal anti-inflammatory drug 2-(4-isobutylphenyl)propionic acid (ibuprofen) and cubane-1,4-dicarboxylic acid (CDA) were covalently linked w ith a-hydroxyethyl methacrylate (HEMA). The drug-linked HEMA (ibuprofen-lin ked HEMA) abbreviated as HI and cubane-1,4-dicarboxylic acid (CDA) linked t o two HEMA groups as CA. A difunctional spacer group was introduced between the drug and acrylic moiety of the monomer through a hydrolyzable ester li nkage. Free radical crosslinking polymerization of the monomer HI with the various ratios CA as crosslinking agent were carried out in DMF, DMSO or di oxane solution, using AIBN as initiator at the temperature range of 60-70 d egrees C. The structure of the monomers was confirmed by FTIR, H-1 NMR and C-13 NMR spectroscopy. The compositions of the crosslinked three-dimensiona l polymers were determined by FTIR spectroscopy. Glass transition temperatu re (T-g) of the network polymers was determined calorimetrically. The hydro lysis of drug-polymer conjugates was carried out in cellophane membrane dia lysis bags containing an aqueous buffer solution (pH 8 and pH 1) at 37 degr ees C. Detection of the hydrolysis product by UV spectroscopy shows that th e drug (ibuprofen) was released by the hydrolysis of the ester bond located between the drug and spacer group.