Peripheral nerve block is performed for precise
pain control and lesser side effects after surgery by reducing
opioid consumption.
Injectable hydrogel delivery systems with high biosafety and moisture content have good clinical application prospects for
local anesthetic delivery. However, how to achieve high drug loading and long-term controlled release of water-soluble
narcotic drugs remains a big challenge. In this study, heterogeneous
microspheres and an
injectable gel-matrix composite drug delivery system are designed in two steps. First, heterogeneous
hydrogel microspheres loaded with
ropivacaine (HMS-ROP) are prepared using a microfluidic chip and in situ alkalization. An
injectable self-healing
hydrogel matrix (Gel) is then prepared from modified
carboxymethylcellulose (CMC-ADH) and oxidized
hyaluronic acid (OHA). A
local anesthetic delivery system, Gel/HMS-ROP/
dexmedetomidine (DEX), with long-term retention and drug release in vivo is prepared by combining HMS-ROP and Gel/DEX. The drug loading of HMS-ROP reached 41.1%, with a drug release time of over 160 h in vitro, and sensory and motor blockade times in vivo of 48 and 36 h, respectively. In summary, the sequential release and synergistic
analgesic effects of the two
anesthetics are realized using core-shell
microspheres, DEX, and an
injectable gel, providing a promising strategy for long-acting
postoperative pain management.