CONTROLLED RELEASE FROM LAYERED NANOSTRUCTURED MATERIALS DRIVEN BY CAPILLARY FORCES

Controlled release of active compounds has been investigated in current medical research and there were developed many approaches, how to control it. For instance, complexation of active compound, encapsulation in matrix, or release from gels. However, there are still opportunities to improve its mechanisms. This contribution presents potentially promising method of controlled release, which is based on two modifications of standard mechanisms: i. release from nanostructured layered material, ii. release forced by capillarity. That mechanism allows us to design systems with gradual release of the active substance. The release of indigotin dye was performed from materials where layers of non-woven chitosan fabric alternate with gelatine layers. Active compound was incorporated in each layer. Gradual wetting of layers is caused by capillarity effect. The controlled release can be observed visually, e.g. by optical spectroscopy. In the future, the colour compound will be substituted by medical active substances, such as antibiotics etc. The final systems will be composed of natural and biocompatible materials, such as polysaccharides and proteins. The active compound will be in synergy with the chitosan matrix. Chitosan is a unique natural polymer with positive charge on the surface, it exhibits mucoadhesive and antibacterial properties. Gelatine was chosen because it is a protein with a negative charge on its surface, which forms a polyionic mixture with positively charged chitosan. Such material will improve the current practice in the field of medical materials. It will allow us to design patches treated with an active substance that could improve the therapeutic effect.