Desai Kashappa Goud, Park Hyun Jin
School of Life Sciences and Biotechnology, Korea University, South Korea.
Drug Deliv. 2006 Jan-Feb;13(1):39-50. doi: 10.1080/10717540500309123.
Gamma (gamma)-irradiation is finding increasing use in the sterilization of pharmaceutical products. However, irradiation also might affect the performance of drug delivery systems. In this study, the influence of gamma-irradiation on the characteristics of chitosan microparticles was investigated. The diclofenac sodium was incorporated into chitosan microparticles by spray-drying method. The chitosan microparticles (placebo and drug-loaded) were irradiated at doses of 5, 15, and 25 kGy using a (60)Co source. Later, the microparticles were characterized by Fourier transform infrared (FTIR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and atomic force microscopy. In addition, microparticles also were evaluated for their sizes, drug content, swelling, and drug release behavior. Encapsulation efficiency of irradiated and nonirradiated microparticles was essentially the same. Notably, surface roughness (rms) of placebo microparticles decreased significantly after gamma-irradiation when compared with nonirradiated placebo microparticles. FTIR spectroscopy revealed that gamma-irradiation of chitosan microparticles induced neither cross-linking nor formation of new group in the chitosan matrix. EPR spectroscopy results showed that the gamma rays induced only one kind of free radical in the chitosan matrix. Size, crystallinity, and thermal properties of the chitosan microparticles did not change much after gamma-irradiation. gamma-irradiated microparticles, exhibited a slightly higher drug release rate and low swelling capacity than the nonirradiated microparticles.
γ射线辐照在药品灭菌中的应用越来越广泛。然而，辐照也可能会影响药物递送系统的性能。在本研究中，考察了γ射线辐照对壳聚糖微粒特性的影响。采用喷雾干燥法将双氯芬酸钠载入壳聚糖微粒中。使用钴-60源对壳聚糖微粒（空白和载药）分别进行5、15和25千戈瑞剂量的辐照。随后，通过傅里叶变换红外光谱（FTIR）、电子顺磁共振（EPR）光谱、X射线衍射、差示扫描量热法、扫描电子显微镜和原子力显微镜对微粒进行表征。此外，还对微粒的粒径、药物含量、溶胀度和药物释放行为进行了评价。辐照和未辐照微粒的包封率基本相同。值得注意的是，与未辐照的空白微粒相比，γ射线辐照后空白微粒的表面粗糙度（均方根）显著降低。FTIR光谱显示，壳聚糖微粒的γ射线辐照在壳聚糖基质中既未诱导交联也未形成新基团。EPR光谱结果表明，γ射线在壳聚糖基质中仅诱导产生一种自由基。γ射线辐照后壳聚糖微粒的粒径、结晶度和热性质变化不大。γ射线辐照的微粒比未辐照的微粒表现出略高的药物释放速率和较低的溶胀能力。
