Resveratrol loaded liposomes produced by different techniques

Abstract

Several different methods for production of liposomes incorporating resveratrol were investigated and compared from the aspect of size distribution, surface charge, entrapment efficiency, phase behavior and stability. Thin film method and proliposome method provided high entrapment efficiency (92.9% and 97.4%, respectively). Extrusion and sonication techniques were applied to obtain particles of the average diameter between 120 and 270 nm. The sonicated liposomes incorporated resveratrol (44-56%) fewer than extruded vesicles (92-96%). Antioxidative activity of resveratrol was retained upon encapsulation. Differential scanning calorimetry was performed in order to study the interaction of liposomal membranes with resveratrol, and their physical state. The release studies performed in Franz diffusion cell showed that liposomes impart slow diffusion of resveratrol, where diffusion resistance derived from liposomal membrane ranged from 5.90 . 10(5) to 9.55 . 10(5) s/m depending on the size of particles. Cytotoxicity of the formulations was evaluated via morphological changes of keratinocytes treated by liposomes. Industrial Relevance: Resveratrol displays many health-beneficial properties and possesses a remarkably strong antioxidant activity. Although often consumed in food, the positive effects of resveratrol are restricted because it is prone to oxidation, poorly absorbed when orally administrated, and cytotoxic in higher total dosages (though relatively high local concentrations are required for an effect). Encapsulation is one way to improve bioavailability and stability of resveratrol; herein the main challenge is to find a suitable solution, as resveratrol is weakly water soluble. This has motivated us to design new formulations based on liposomes for delivering of resveratrol. In the food sector, liposomes have been investigated for delivering proteins, enzymes, antioxidants, flavors and vitamins. The mean advantage of liposomes over other encapsulation technologies (spray-drying, extrusion, and fluidized beds) is the stability that liposomes impart to water-soluble compounds in aqueous surroundings. Liposomes are able to stabilize the encapsulated materials against a range of environmental and chemical changes. Another important characteristic of liposomes is that, unlike many other existing encapsulants, they can be utilized in the entrapment, delivery, and release of poorly water soluble compounds, such as resveratrol, and they are also convenient for water-soluble, lipid-soluble, and amphiphilic compounds. As liposomes could be produced from naturally occurring components, regulatory issues that may prevent the application in food systems are potentially diminished, and new formulations could be quickly implemented. Despite benefits described here, up to date little use of liposomes in food systems has been made, as current manufacturing processes are mainly time consuming, often consisting of several steps with high costs of raw materials. Another problem is that devices available commercially which are utilized for production of liposomes are able to process only small quantities. Therefore, our research is devoted to the development of the process for liposome production which is easy to scale up, and at the same time, is effective as the common way based on thin film hydration process. The process elaborated in our study utilizes a commercial lipid mixture. The method used called proliposome method is based on replacement of ethanol solvent by aqueous media. For liposome downsizing, sonication (which can be easily modified to increase sample volume capability) is tested versus membrane extrusion (equipment for small-large batches is readily available). The goal of this article is to provide evidence for food manufacturers and food scientists to make broader use of resveratrol-loaded liposomes that can add value and improve the quality of existing food products.