Faculty of Science, Engineering and Technology, Swinburne University of Technology, Melbourne, Victoria, Australia.
J Colloid Interface Sci. 2014 Aug 15;428:286-94. doi: 10.1016/j.jcis.2014.04.057. Epub 2014 May 4.
Solid lipid nanoparticles (SLNs) produced by conventional microemulsion techniques using thermal heat have specific limitations (e.g. high polydispersity, instability and low encapsulation). Replacing thermal heat with microwave heat may produce SLNs which overcome some of these limitations.
Stearic acid-based SLNs prepared with Tween® 20 as the emulsifier were chosen as the optimum formulation to encapsulate and potentially deliver the antibacterial drug tetracycline. All formulations were characterized for their particle size, zeta potential, encapsulation efficiency, loading capacity, thermal and X-ray diffraction analyses. Short-term stability and in vitro drug studies were also performed.
Microwave heating helps to overcome several disadvantages associated with thermal heating (nonuniform, inefficient and slow) and results in improved particle characteristics. There is thus the potential for new opportunities in the development of colloidal carriers. The particle sizes of microwave-produced SLNs were in the desired nanometer range (200-250 nm) with both lower size and lower polydispersity than the conventional SLNs. We take this as an indication of improved stability; however zeta potential measurements were not different, indicating similar stability. True stability testing (visual observation with time) did show that the microwave-induced SLNs were found to be more stable, particularly when refrigerated. The microwave-produced SLNs also demonstrated improved encapsulation efficiency and loading capacity. Thermal and diffraction analysis confirmed a lowered crystallinity of stearic acid with successful incorporation of tetracycline into the SLNs. In vitro release studies indicated that, after an initial burst release, SLNs could provide prolonged release of tetracycline. The presence of tetracycline and non-toxicity of carriers towards microbes was confirmed by antimicrobial susceptibility tests.
通过传统微乳液技术利用热产生的固体脂质纳米粒（SLN）具有特定的局限性（例如高多分散性、不稳定性和低包封率）。用微波热代替热可能会产生克服这些限制的 SLN。
选择以吐温® 20 为乳化剂的硬脂酸为基础的 SLN 作为最佳配方，以包封和潜在递送至抗生素药物四环素。所有配方均进行了粒径、Zeta 电位、包封效率、载药量、热和 X 射线衍射分析。还进行了短期稳定性和体外药物研究。
微波加热有助于克服与热加热相关的几个缺点（不均匀、效率低和缓慢），并导致颗粒特性得到改善。因此，在胶体载体的开发方面可能会有新的机会。微波产生的 SLN 的粒径在所需的纳米范围内（200-250nm），比常规 SLN 具有更小的粒径和更低的多分散性。我们认为这是稳定性提高的迹象；然而，Zeta 电位测量结果没有差异，表明稳定性相似。真正的稳定性测试（随着时间的视觉观察）确实表明，微波诱导的 SLN 更稳定，特别是在冷藏时。微波产生的 SLN 还表现出更高的包封效率和载药量。热和衍射分析证实硬脂酸的结晶度降低，四环素成功地掺入 SLN 中。体外释放研究表明，在初始突释之后，SLN 可以提供四环素的延长释放。通过抗菌药敏试验证实了四环素的存在和载体对微生物的非毒性。
