原位共沉淀法制备载药Fe3O4/壳聚糖磁性复合微球及其体外药物释放行为

以核黄素为药物模型，采用原位共沉淀法制备了一种载药Fe₃O₄/壳聚糖复合微球。傅里叶变换红外光谱（FTIR）、透射电子显微镜（TEM）、场发射扫描电子显微镜（FESEM）和振动磁强计（VSM）表征了复合微球的化学组成、外观形貌以及磁性能。结果表明，制备的载药Fe₃O₄/壳聚糖复合微球平均粒径约为40 nm且粒径均匀，平均磁响应时间为52 s，饱和磁化强度为3.313 2 A·m²·kg^-1。采用紫外/可见（UV/Vis）分光光度计考察了复合微球的药物包封率、载药量（质量分数），并对微球在模拟胃液、模拟肠液、生理盐水、葡萄糖溶液和二次蒸馏水中的释药行为进行跟踪。结果表明，微球的载药量可达9.9%，药物包封率为70.8%，实验条件下在模拟肠液中具有显著的缓释效果，释放10 h药物累积释放16.06%，60 h达52.18%。

Preparation of Fe3O4 /chitosan magnetic composite particle loading drug by co-precipitation in situ and its release behavior in vitro

A Fe₃O₄/chitosan magnetic composite particle loading riboflavin used as model of drug is prepared through a co-precipitation process in situ. The chemical component, morphology and magnetic property were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscope (TEM), field emission scanning electron microscopy (FESEM) and vibrating sample magnetometer (VSM), respectively. The results show that the diameter of a typical Fe₃O₄/chitosan composite particle is about 40 nm and the distribution is uniform, the average magnetic response time is 52 s, and the strength of saturation magnetization is 3.313 2 A·m²·kg^-1. The drug content (mass fraction), the drug loading efficiency and the in vitro release profiles under simulated gastric fluid, simulated intestinal fluid, saline, glucose solution using in medicine and redistilled water were investigated using UV/Vis spectrophotometry, respectively. The results show that the drug content is about 9.9%, the drug loading efficiency reaches 70.8%, and the Fe₃O₄/chitosan composite particle displays an excellent drug controlled release behavior under the experimental conditions of the simulated intestinal fluid. Less than 16.06% of the drug is released from composite particle after 10 h but up to 52.18% after 60 h.