Designing and fabrication of zein-ethylcellulose based nano-system using antisolvent method and evaluation of curcumin encapsulation

Abstract

Abstract Background: Nowadays in world, due to the epidemicof diseases such as cardiovascular diseases and different types of cancers, much attention has been paid to their prevention by appropriate diet. There are many bioactive substances of natural origin, which have several health properties. These include resveratrol and curcumin, which are bioactive substances with many properties, including antioxidant, anti-cancer, effective in cardiovascular diseases, etc. However, due to their low bioavailability and degradation in the gastrointestinal tract, their properties can not be used. Therefore, a lot of attention has been paid to nanotechnology to protect, encapsulate materials, deliver them to the target tissue, and use these nanosystems in food and daily diet. Zein is a protein that has been used extensively in nanotechnology and nanoencapsulation of bioactive materials and has shown promising results in this field. But in addition to its benefits, it has deficiency as well. To compensate for these deficiencies, we decided to use a secondary coating layer of ethylcellulose, which covers the drug, delivers the drug and releasing it in the colon. Given that until now, no research has been done on a nanosystem with the desired specifications and unique benefits, the following purpose was considered for this research. The purpose: Design and fabrication of zein-ethylcellulose based nano-system using antisolvent method and evaluation of curcumin encapsulation Materials and Methods: For zein-curcumin-ethylcellulose nanosystem preparation, firstly, zein was dissolved at 10 ml ethanol 80%v/v and was stirred at 500 rpm at room temperature for 30 min. Then curcumin was added to zein in ethanol and stirred in darkness at 500 rpm for 90 min. Then 20 ml water was added to the solution as an anti-solvent phase under stirring at 1000 rpm for 5 min. In the second step, ethylcellulose separately was dissolved in ethyl acetate under magnetic stirring at 500 rpm for at least one hour at ambient temperature. Then ethylcellulose/ethyl acetate solution was added to the colloidal suspension zein/curcumin using 5-ml syringe and the feeding rate was set at 2 ml/h, and finally, ethanol and ethyl acetate was removed from the sample with rotary evaporation at 45 °C for 10 min under vacuum. Then samples were kept in darkness And monitored for seven days. Finally, the most appropriate formulations were selected based on physical stability and appearance of colloidal suspensions for further analyses including particle size, zeta potential measurements, fluorescence spectroscopy, encapsulation efficiency, particle yield, fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), the release of curcumin from nanoparticles due to changes of pHs and antioxidant activity of curcumin. For experiments that required powdered samples, the samples were freeze-dried. Results: Zein-curcumin-ethylcellulose nanosystem was successfully developed for the first time by two-stage liquid anti-solvent method. The solvent ratio, anti-solvent and materials are beneficial in the system producing and its stability. According to fluorescence spectroscopy, curcumin was able to complex well with zein. The nanoparticles of the final system had particle diameters about 170 nm, zeta potential values +12 mV. The final system's encapsulation efficiency was above 50% and the particle yield was above 90%, which indicates the sufficiency of the method. According to the FTIR spectra, it can be said that curcumin was successfully coated inside the zein-ethylcellulose nanoparticles, and most of the specific curcumin peaks disappeared in the spectrum of the final system, which is related to the formation of complex between curcumin and nanoparticles. Changes in nanoparticles are visible in SEM images after the addition of ethylcellulose. The nanoparticles were perfectly spherical shape with a smooth surface. The final nanosystem thermal stability was increased after the addition of ethylcellulose to the system. With ethylcellulose's addition to the final nanosystem, the system's stability against pH changes was significantly increased. The final nanosystem was completely stable in the pH range of 3-8, and the release of curcumin was below 2%. By measuring the antioxidant activity of zein-curcumin-ethylcellulose nanoparticles after six months storage and comparison with pure curcumin, found that this system was able to protect curcumin against destructive environmental conditions. Conclusion: In this research, for the first time, a two-stage liquid anti-solvent method was used to produce nanoparticles. in this research, for the first time, we were able to convert three hydrophobic materials into water-soluble nanoparticles with high stability and successfully make the zein-curcumin-ethylcellulose nanosystem. According to the results of this study, it is expected that the designed nanosystem can be used in foods and used its many health properties to prevent and treat cancers. Keywords: Zein, Ethylcellulose, Curcumin, Anti-solvent Method