Preparation of the poly(n-butyl α-cyanoacrylate) nanocapsules by interfacial polymerization

Because poly(butyl alpha-cyanoacrylate) was less toxic than poly(isobutyl alpha-cyanoacrylate)and its nanocapsules could be orally absorbed via intestine wall, the polymeric nanocapsules as drug delivery system of peptides was prepared by the interfacial polymerization of butyl alpha-cyanoacrylate other than isobutyl alpha-cyanoacrylate used previously. The aqueous phase contained a surfactant such as Tween 20 and polymeric stabilizer such as dextrin T-70, dextrin T-40 as well as Poloxamer 188. And the organic phase composed of monomer butyl alpha-cyanoacrylate and a cosolvent such as glycerol trioleate or benzyl alcohol in bulky solvent ethanol or acetone. The nanocapsule sizes and their distribution were measured by laser scattering technique and transmission electron micrography. It was investigated the influence of the used surfactants, polymeric stabilizers,cosolvents, and temperature in vacuum evaporation on the nanocapsule sizes. The results show that dextrin T-70 is a better polymeric stabilizer than its low molecular weight analog dextrin T-40 and Poloxamer 188 for the monomer phase soluble in ethanol to be dispersed in aqueous phase with Tween 20 as a surfactant. The size of the polymeric nanocapsules decreased with increase of amounts of dextrin T-70 and Tween 20 dissolved in aqueous phase. Compared with glycerol trioleate, benzyl alcohol as cosolvent could made the nanocapsules larger and smoother because benzyl alcohol might make the immigration of the solvent, ethanol, in the monomer phase into aqueous phase more slowly. In addition, when the formed suspension of poly(butyl alpha-cyanoacrylate) nanocapsules was concentrated by evaporation in vacuum at 30 degrees C instead of 20 degrees C, small nanocapsules would be aggregated into large particles.