Hyaluronic acid-based hydrogels: Drug diffusion investigated by HR-MAS NMR and release kinetics

Hydrogels based on hyaluronic acid (HA) and agarose-carbomer (AC) raised an increasing interest as drug delivery systems. The complex architecture of the polymer network, such as mesh size, HA molecular weight and drug-polymer non covalent interactions across the 3D polymer matrix strongly influence the release capability/profile of these materials. In this study, AC-HA hydrogels with different mesh sizes have been prepared and characterised. High Resolution Magic Angle Spinning (HR-MAS) NMR spectroscopy has been used to investigate the motion of two drugs, such as ethosuximide (neutral molecule) and sodium salicylate (net negative charge) within the AC and AC-HA hydrogel networks. Analysis of the experimental data provides evidence of superdiffusive motion for all formulations containing sodium salicylate, while ethosuximide molecules undergo unrestricted diffusion within the gel matrix. We further speculate that the superdiffusive motion, observed at the nanoscale, can be responsible for the faster release of sodium salicylate from all hydrogel formulations

Exploiting Inherent Instability of 2D Black Phosphorus for Controlled Phosphate Release from Blow-Spun Poly (lactide-co-glycolide) Nanofibers

Efforts have been made to stabilize black phosphorus (BP) to utilize its tunable band gap and anisotropic mechanical properties. Here, the intrinsic instability of BP is exploited for controlled therapeutic ion release, namely phosphate. BP was incorporated into degradable poly (lactide-co-glycolide) fibers via solution blow spinning. Raman spectroscopy confirmed the incorporation of 2D-BP into the nanocomposite along with ICP-AES. It was also demonstrated that modifying the initial loading of 2D-BP in the PLGA fibers permitted tunable release rates of phosphate ions over an 8 weeks in vitro study