Cisplatin delivery from poly(acrylic acid-co-methyl methacrylate) microparticles

To develop a platform for tumor chemotherapy, poly(acrylic acid-co-methyl methacrylate) microparticles have been synthesized. Carboxylate containing monomers were included to complex therapeutic agents, specifically cisplatin. Microparticles were prepared by free radical emulsion polymerization in aqueous media. Particle diameter, ζ-potential, in vitro cytotoxicity, and in vivo acute toxicity were characterized for both cisplatin-loaded microparticles and unloaded microparticles. In vitro cytotoxicity and FT-IR were used to characterize cisplatin released from cisplatin-loaded microparticles. Acrylic acid feed mole fraction determined several key microparticle properties, including particle size, ζ-potential, and yield. A burst release of cisplatin (40%) in the first day was followed by a zero-order release phase. The interaction between cisplatin and microparticles allowed approximately 20% additional cisplatin release in the next five days. Cisplatin-loaded and unloaded microparticles are non-toxic (LC50 > 15 mM) to the cell line used in in vitro tests. Cisplatin released from cisplatin-loaded microparticles retained activity, but that activity was slightly lower than freshly prepared cisplatin. Other than a slight reduction in cisplatin activity, microparticles exhibited low in vivo acute toxicity (LD50 > 170 mg/kg), which suggests that this hydrogel particulate system and the hydrogel complexation mechanism should further be studied for drug delivery.