Effects of external phase on D-cycloserine loaded W/O nanocapsules prepared by the interfacial polymerization method

Water in oil (W/O) polybutylcyanoacrylate nanocapsules containing D-cycloserine (D-CS) for intranasal delivery were prepared by the interfacial polymerization method. Different oils, as external phase, for the preparation of the initial W/O miniemulsions were used and their effect on mean size and other physico-chemical properties were evaluated by photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM) analysis. Two probes at different hydrophilicity were used to verify the internal aqueous nature of the core. Both miniemulsions and nanocapsules mean size and polydispersity index were influenced by the used external phase. Different entrapment efficiency were obtained for D-cycloserine-loaded nanocapsules correlated to the used oil [ranging from 39 to 51% encapsulation efficiency (E.E.)]. In vitro drug release showed an initial burst effect (ranging from 20 to 40%) followed by a slow release of D-CS for all preparations. This study demonstrated that many relevant physico-chemical and technological properties of polybutylcyanoacrylate nanocapsules prepared by interfacial polymerization of miniemulsions are significantly influenced by the external oil phase used.

SEM picture shows nanoparticles with an external grey-coloured frame and an internal light core that could evidence the capsular structure.Two probes with different hydrophilicity were used to verify the aqueous nature of the core.Figure optionsDownload as PowerPoint slideHighlights
► W/O polybutylcyanoacrylate nanocapsules loading D-cycloserine were prepared.
► Mean sizes and ζ-potential of nanocapsules were influenced by formulation parameters.
► Aqueous nature of the core was confirmed by high encapsulation percentage of calcein.
► D-cycloserine is probably located both in the aqueous core and in the polymeric shell.
► After a burst effect a prolonged release of D-cycloserine was observed.