Niosomes formation using a continuous supercritical CO2 assisted process

The production of biocompatible nanocarriers, to induce a controlled, sustained and/or targeted drug delivery, is a fascinating nanotechnology challenge. Among the possible nanocarriers, niosomes are non-ionic compounds, with a lipophilic tail and a hydrophilic head, that can self-assemble in aqueous dispersions and can show a good stability over time. In this work, a continuous process, assisted by supercritical CO2, was used for the production of empty and theophylline loaded niosomes. The optimal results, in terms of niosomes nanometric dimension and stability verified up to 30 days, were obtained processing an ethanolic solution at a 90/10 Span® 80 to Tween® 80 ratio. A drug encapsulation efficiency of 85 % was measured when the supercritical process was carried out using a water flow rate of 1 mL/min. Theophylline release time was prolonged up to 5-folds, when this active compound was loaded in niosomes prepared at the largest surfactant to water ratio (100 mg/g).