Preparation And In Vitro Release Of The Magnetic Nano-drug Carriers

The magnetic nano-drug carriers can be transported and delivered at a targeted pathological site and exhibit a controlled/sustained drug release to achieve maximum therapeutic efficacy with minimal toxicity. In this work, the magnetic nano-drug carriers was prepared by sunflower pectin coated Fe₃O₄ for cancer targeting of 5-FU. Furthermore, the in vitro release of magnetic nano-drug carriers were evaluated.The browning inhibition in the preparation process of sunflower pectin was investigated and optimized by orthogonal design. The results showed that the best browning inhibitor was 30.0 g/L citric acid, 1.5 g/L L-cysteine hydrochloride and 0.7 g/L sodium hydrogen sulfite. The degree of esterification of the pectin was 25.34%, and the weight average molecular weight and the number average molecular weight were 379000 Da and 311000 Da, respectively.Fe₃O₄ magnetic fluids modified by sodium citrate, were prepared by co-precipitation method. The effects of various paramaters on the properties of Fe₃O₄ magnetic fluids such as temperature, stirring rate, the quantity of sodium citrate were studied and optimized. The optimum condition was the temperature of 50℃, stirring rate of 600 r/min and sodium citrate of 1.0 g. Fe₃O₄ magnetic fluids modified by sodium citrate had a smaller size and could be stability in watery environment.Sunflower pectin coated Fe₃O₄ for cancer targeting of 5-FU was prepared by embedding method. The preparation process was optimized by response surface methodology. A mixture of 1.9 g/L sunflower pectin, 6.0 g/L Ca2+, the crosslinking time of 4 h and the temperature of 27℃ was optimum, which resulted in the higher drug encapsulation efficiency. The diameter of prepared magnetic nano-drug carriers were 20 nm. The saturation magnetization value of magnetic nano-drug carriers was 20.78 emu/g and the magnetic nano-drug carriers could be easily controlled by an external magnetic field in watery environment.The effects of drying method on in vitro release properties of magnetic nano-drug carrier was investigated. In the same release medium, the in vitro drug release quantity of magnetic nano-drug carriers after being freeze-drying was more than that of being oven drying. The magnetic nano-drug carriers after being oven drying exhibited excellent sustained release properties in gastrointestinal tract environment, particularly in the large intestine, which had the drug release quantity of 90.90%. The freeze-dried magnetic nano-drug carriers exhibited a burst release in simulate intestines liquid, showing a poor sustained release property.