Nanochocleates: stable and efficient nanocarriers of essential oils

Nanocochleates (NCs) are cylindrical (cigar-like) nano- and microstructures that consist of a series of phospholipid bilayers rolled up in a spiral or in stacked sheets, with little or no internal aqueous space [1]. Their simple structure is formed of negatively charged phospholipid bilayers through the interaction with multivalent counter ions (Ca2+ or Zn2+) as bridging agents between the bilayers. NCs possess unique properties like superior mechanical stability and better protection for encapsulated drugs compared with liposomes due to their solid matrix. They can be stored by freeze drying, maintaining their structure even after lyophilisation and are easy to produce. This innovative nanocarriers have no inflammatory properties and are completely biodegradable. Diverse NCs encapsulating essential oils of aromatic plants from Italian biodiversity were investigated. NCs loaded with thyme essential oil (TEO) at the concentration of 0.5 mg/ml and 1 mg/ml possess optimal characteristics in terms of size (ca. 200nm) and encapsulation efficiency (more than 50%) and were selected for further studies. In vitro release of TEO principal constituents, thymol and carvacrol, indicated a steady release in the first hour (ca. 26% and 36% of carvacrol and thymol respectively). After 6 hours ca. 41% and 31% for thymol and carvacrol were released. Stability studies showed the formulation was stable at least for two months. Finally DDPH test established that formulation is able to preserve the antioxidant activity of TEO components, namely 75.2% (free TEO) versus 72.2% (formulation). In conclusion NCs represent a stable, efficient and innovative nanocarrier to deliver essential oils having high stability, easy to lyophilize, high loading efficiency, non-toxic, non-immunogenic and without inflammatory al conditions such as lights, oxygen, water and temperature [2]. properties, easily and safely produced and able to protect essential oil from environment.