Synthesis of Poly(Alkyl Cyanoacrylates) as Biodegradable Polymers for Drug Delivery Applications

Poly(alkyl cyanoacrylates) are biodegradable and biocompatible polymers. Ethyl, n-butyl and octyl cyanoacrylate have been approved in the last decades by the US Food and Drug Administration (FDA) and novel applications are continuously appearing. Recently, such polymers have been proposed as raw materials for the synthesis of nanoparticles aimed to drug delivery. In the literature, such nanoparticles have been always produced through heterogeneous polymerization processes in water. In this work, the anionic polymerization of ethyl, n-butyl and octyl-cyanoacrylate in water is systematically investigated. Optimum conditions for the process are identified by changing reaction temperature and solution pH. It is found that an aqueous dispersion medium at pH around 5 and 65 °C gives the best results in terms of polymer molecular weight for all monomers, even if the process exhibits the dominant production of low molecular weight (LMW) polymer. On the other hand, the amount of high molecular weight polymer becomes noticeable at room temperature.