Wang Feng, Barnes Timothy J, Prestidge Clive A
School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, SA 5000, Australia.
ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, University of South Australia, Adelaide, SA 5000, Australia.
Pharmaceutics. 2019 Nov 28;11(12):634. doi: 10.3390/pharmaceutics11120634.
Porous silicon (pSi) continues to receive considerable interest for use in applications ranging from sensors, biological scaffolds, therapeutic delivery systems to theranostics. Critical to all of these applications is pSi degradation and stabilization in biological media. Here we report on progress towards the development of a mechanistic understanding for the dissolution behavior of native (unoxidized) and thermally oxidized (200-600 °C) pSi microparticles. Fourier transform infrared (FTIR) spectroscopy was used to characterize the pSi surface chemistry after thermal oxidation. PSi dissolution was assessed using a USP method II apparatus by monitoring the production of orthosilicic acid, and the influence of gastro-intestinal (GI) fluids were examined. Fitting pSi dissolution kinetics with a sum of the exponential model demonstrated that the dissolution process strongly correlates with the three surface hydride species and their relative reactivity, and was supported by the observed FTIR spectral changes of pSi during dissolution. Finally, the presence of GI proteins was shown to hamper pSi dissolution by adsorption to the pSi surface acting as a barrier preventing water attack. These findings are significant in the optimal design of pSi particles for oral delivery and other controlled drug delivery applications.
多孔硅（pSi）在从传感器、生物支架、治疗递送系统到诊疗学等一系列应用中持续受到广泛关注。对于所有这些应用而言，pSi在生物介质中的降解和稳定性至关重要。在此，我们报告了在对天然（未氧化）和热氧化（200 - 600°C）pSi微粒的溶解行为形成机理理解方面所取得的进展。利用傅里叶变换红外（FTIR）光谱对热氧化后的pSi表面化学性质进行了表征。通过监测原硅酸的生成，使用美国药典方法II装置评估了pSi的溶解情况，并研究了胃肠（GI）液的影响。用指数模型之和拟合pSi溶解动力学表明，溶解过程与三种表面氢化物种类及其相对反应活性密切相关，并且在溶解过程中观察到的pSi的FTIR光谱变化也证实了这一点。最后，研究表明GI蛋白质的存在会通过吸附在pSi表面形成屏障阻止水的侵蚀，从而阻碍pSi的溶解。这些发现对于口服递送和其他控释药物递送应用中pSi颗粒的优化设计具有重要意义。
