Drug release from alfa, beta-poly(N 2-hydroxyethyl)-dl -aspartamide-based microparticles

Spherical pH-sensitive microparticles have been prepared by reverse phase suspension polymerization technique. Starting polymerhas been a,b-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) partially derivatized with glycidylmethacrylate (GMA). PHEAGMAcopolymer (PHG) has been crosslinked in the presence of acrylic acid (AA) or methacrylic acid (MA) at variousconcentration. The obtained microparticles have been characterized by FT-IR spectrophotometry, particle size distribution analysisand scanning electron microscopy. In order to have information about water affinity of the prepared samples, swellingmeasurements have been carried out in aqueous media which simulate some biological fluids. The possibility to employ the preparedsamples as pH-sensitive microparticles has been investigated by performing in vitro release studies. Experimental data have showedthat the release rate from these microparticles depends on the environmental pH and the chemical structure of the drug.