Abrami Michela, Bignotti Fabio, Baldi Francesco, Spagnoli Gloria, Biasin Alice, Grassi Lucia, Grassi Gabriele, Grassi Mario
Department of Engineering and Architecture, University of Trieste, Via Valerio 6/A, I-34127 Trieste, Italy.
Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, I-25123 Brescia, Italy.
Int J Pharm. 2023 Apr 25;637:122882. doi: 10.1016/j.ijpharm.2023.122882. Epub 2023 Mar 21.
The focus of this work is on the characterization of hydrophobically-modified polyethylene glycol hydrogels, to be used as drug delivery systems, by means of the combined used of rheology and low field Nuclear Magnetic Resonance. Indeed, these two techniques allowed understanding how the transient physical bonds deriving from hydrophobic association superimpose to the pre-existing covalent bonds. We found that the improvement of physical bonds can be achieved not only by increasing the content of hydrophobic segments but also by using thermal treatments after hydrogel preparation. Moreover, we proved the reliability of an overall interpretative model linking the dependence of the shear modulus and the average magnetic relaxation time. Finally, we proposed a new mathematical approach for the determination of the magnetic relaxation spectrum. This approach reduced the computational heaviness of the procedure and allowed to easily discern the different contributes nested in the overall magnetic relaxation spectrum, an aspect that the traditional approach cannot provide directly.
这项工作的重点是通过流变学和低场核磁共振相结合的方法，对用作药物递送系统的疏水改性聚乙二醇水凝胶进行表征。事实上，这两种技术能够理解疏水缔合产生的瞬态物理键如何叠加到预先存在的共价键上。我们发现，不仅可以通过增加疏水链段的含量，还可以通过在水凝胶制备后进行热处理来实现物理键的改善。此外，我们证明了一个将剪切模量和平均磁弛豫时间的依赖性联系起来的整体解释模型的可靠性。最后，我们提出了一种用于确定磁弛豫谱的新数学方法。这种方法降低了该过程的计算量，并能够轻松辨别嵌套在整体磁弛豫谱中的不同贡献，而传统方法无法直接提供这方面的信息。
