FREEZE-FRACTURE ELECTRON-MICROSCOPY AND LIGHT-SCATTERING-STUDIES POLYETHYLCYANOACRYLATE NANOCAPSULE COLLOIDAL SUSPENSIONS

Nanocapsule preparative procedures are able to change the availability of drugs from delivery devices. In particular, the influence of the o rganic solvent, used in the interfacial polymerisation process, on the shape, mean particle size, size distribution and type of colloidal su spension was investigated. The organic solvents employed in the prepar ation of PECA nanocapsules were ethanol, acetone or acetonitrile. A no n-ionic surfactant (Pluronic F68) was used during the preparation proc ess. The amount of monomer represented another variable, capable of in fluencing the final carrier properties of PECA nanocapsules. The prese nce of ethanol achieved the formation of both nanoparticles and nanoca psules. However, the presence of acetone or acetonitrile achieved not only a highly homogeneous size colloidal system, but also the formatio n of only one type of PECA nanosphere (nanocapsule). The different amo unt of monomer led to the formation of nanocapsules with a wall thickn ess proportional to the initial concentration of the polymerising agen t.