Influence of the preparation conditions on poly(ethylcyanoacrylate) nanocapsule formation.

Poly(ethylcyanoacrylate) (PECA) nanocapsules suitable for use as drug delivery systems were prepared by in situ polymerization, adding the monomer to an organic phase and subsequent mixing of the latter to an aqueous phase containing a nonionic surfactant. Different preparation conditions have been able to influence the final PECA nanocapsule colloidal suspension. In particular, the kind of organic solvent caused the formation of either simple PECA nanocapsule suspensions (aprotic fully water-miscible solvents) or PECA nanoparticle colloidal suspensions consisting of nanospheres and nanocapsules (protic water-miscible solvent). Both mechanisms, the interfacial precipitation of a pre-formed polymer and the interfacial polymerization, could play a significant role in nanocapsule formation. Also other variables, such as the kind of the nonionic surfactant and the monomer concentration, affected in different ways the nanocapsule formation process.