W M Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA.
Mater Sci Eng C Mater Biol Appl. 2013 Aug 1;33(6):3121-8. doi: 10.1016/j.msec.2013.02.049. Epub 2013 Mar 14.
The approach of local drug delivery from polymeric coating is currently getting significant attention for both soft and hard tissue engineering applications for sustained and controlled release. The chemistry of the polymer and the drug, and their interactions influence the release kinetics to a great extent. Here, we examine lovastatin release behaviour from polycaprolactone (PCL) coating on β-tricalcium phosphate (β-TCP). Lovastatin was incorporated into biodegradable water insoluble PCL coating. A burst and uncontrolled lovastatin release was observed from bare β-TCP, whereas controlled and sustained release was observed from PCL coating. A higher lovastatin release was observed pH7.4 as compared to pH5.0. Effect of PCL concentration on lovastatin release was opposite at pH7.4 and 5.0. At pH5.0 lovastatin release was decreased with increasing PCL concentration, whereas release was increased with increasing PCL concentration at pH7.4. High Ca(2+) ion concentration due to high solubility of β-TCP and degradation of PCL coating were observed at pH5.0 compared to no detectable Ca(2+) ion release and visible degradation of PCL coating at pH7.4. The hydrophilic-hydrophobic and hydrophobic-hydrophobic interactions between lovastatin and PCL were found to be the key factors controlling the diffusion dominated release kinetics of lovastatin from PCL coating over dissolution and degradation processes. Understanding the lovastatin release chemistry from PCL will be beneficial for designing drug delivery devices from polymeric coating or scaffolds.
聚合物涂层的局部药物输送方法目前在软组织和硬组织工程应用中受到广泛关注，因为它可以实现持续和控制药物释放。聚合物和药物的化学性质及其相互作用在很大程度上影响释放动力学。在这里，我们研究了洛伐他汀从β-磷酸三钙（β-TCP）上的聚己内酯（PCL）涂层中的释放行为。将洛伐他汀掺入可生物降解的不溶于水的 PCL 涂层中。从裸β-TCP 观察到洛伐他汀的爆发性和不受控制的释放，而从 PCL 涂层则观察到受控和持续的释放。在 pH7.4 时观察到比 pH5.0 时更高的洛伐他汀释放。在 pH7.4 和 5.0 时，PCL 浓度对洛伐他汀释放的影响相反。在 pH5.0 时，随着 PCL 浓度的增加，洛伐他汀的释放减少，而在 pH7.4 时，随着 PCL 浓度的增加，释放增加。与 pH7.4 时不可检测到 Ca(2+)离子释放和 PCL 涂层可见降解相比，由于高溶解度的β-TCP 和 PCL 涂层的降解，在 pH5.0 时观察到高 Ca(2+)离子浓度。发现洛伐他汀和 PCL 之间的亲水性-亲脂性和疏水性-亲脂性相互作用是控制洛伐他汀从 PCL 涂层扩散主导的释放动力学的关键因素，超过了溶解和降解过程。了解 PCL 中洛伐他汀的释放化学将有助于设计来自聚合物涂层或支架的药物输送装置。
