Degradable UV-Crosslinked Alginate Hydrogels for Sustained Delivery of Hydrophobic Drugs from Embedded PLGA Particles

The development of effective carriers for the delivery of hydrophobic drugs is crucial for enhancing therapeutic outcomes, particularly in cancer treatment. This study explores the use of UV-crosslinked oxidised alginate hydrogels embedded with poly(lactide-co-glycolide) (PLGA) particles for sustained drug release, where Rhodamine B (RhB) was used as a model of small molecule to probe encapsulation and release behaviour. PLGA particles prepared by emulsion solvent evaporation technique remained morphologically stable over seven days, exhibiting modest swelling and a reduction in modulus consistent with early-stage polymer hydration. Release studies revealed a biphasic pattern with an initial burst followed by sustained release. Alginate oxidation and methacrylation enabled tunable hydrogel degradation, with optimised polymer forming networks that balanced structural integrity with gradual mass loss. Composite hydrogels containing PLGA particles promoted a slow and sustained release of RhB, with confocal microscopy confirming the presence of RhB within the hydrogel matrix. The study demonstrates how polymer modification, particle properties, and network degradation can be integrated to modulate release behaviour in degradable hydrogel–particle composites.