Karaya Gum‐Containing Thermosensitive Hydrogels for Controlled Release of Lidocaine in Short‐ and Long‐Term Analgesia
Daniel A. González Palafox, Ana V. Torres‐Figueroa, Andya J. Ramírez‐Irigoyen, Jesús M. Quiroz Castillo, Daniel Fernández‐Quiroz, Hisila del Carmen SantacruzOrtega, Silvia Burruel‐Ibarra, Lerma H. Chan‐Chan, Cinthia J. Pérez‐Martínez, María I. Silvas‐García, Teresa del Castillo‐CastroAbstract
Natural gums are widely available, biocompatible polymers that can be strategically employed to design novel stimuli‐responsive materials to fulfill the specific requirements of the drug delivery carriers. This study developed multifunctional semi‐interpenetrating networks (s‐IPNs) by integrating karaya gum (KG), a bioactive adhesive biopolymer, with a thermosensitive poly(N‐isopropylacrylamide) (pNIPAAm) network. KG improved the compressive strength of pNIPAAm up to threefold and enhanced the hydrogel swelling at pH 7.4 and 5.5, at 25 and 37 °C. The s‐IPNs exhibited a lower volume phase transition temperature than pNIPAAm alone. Additionally, KG increased the lidocaine hydrochloride (LH)‐entrapment efficiency of the s‐IPN to 65% compared to 47% in the hydrogel without KG. The synergistic effect of KG content, LH loading, and physiological skin conditions (pH 5.5, 37 °C) enhanced the bioadhesiveness of the hydrogels. Notable, 71% of the drug was released from the s‐IPN in its relaxed state within 3 h under normal skin conditions, while 80% of LH was delivered sustainably over 17 h from initially dehydrated s‐IPN. The dual temperature‐ and pH‐responsive s‐IPNs demonstrated the promising potential for biomedical applications, particularly for controlled LH release, supporting both short‐ and long‐term analgesic effects.