Injectable Hydrogel Delivery System with High Drug Loading for Prolonging Local Anesthesia

Area of Science:

• Biomaterials Science
• Anesthesiology
• Drug Delivery Systems

Background:

• Peripheral nerve blocks offer precise pain control with fewer side effects than systemic opioids post-surgery.
• Injectable hydrogels are promising for local anesthetic delivery due to their biocompatibility and hydration.
• Achieving high drug loading and sustained release of water-soluble anesthetics remains a significant challenge.

Purpose of the Study:

• To design a two-step injectable composite drug delivery system for long-term local anesthetic delivery.
• To achieve high drug loading and controlled release of ropivacaine and dexmedetomidine.
• To evaluate the in vivo efficacy of the developed system for prolonged postoperative pain management.

Main Methods:

• Preparation of heterogeneous hydrogel microspheres loaded with ropivacaine (HMS-ROP) using microfluidics.
• Fabrication of an injectable self-healing hydrogel matrix (Gel) from modified carboxymethylcellulose and oxidized hyaluronic acid.
• Development of a composite system (Gel/HMS-ROP/dexmedetomidine) for sustained drug release.

Main Results:

• HMS-ROP achieved a drug loading of 41.1% and in vitro release exceeding 160 hours.
• The composite system demonstrated in vivo sensory and motor blockade durations of 48 and 36 hours, respectively.
• Sequential release and synergistic analgesic effects were observed.

Conclusions:

• The developed injectable hydrogel system enables high drug loading and long-term controlled release of local anesthetics.
• The system provides prolonged postoperative pain management through sequential release and synergistic effects.
• This strategy offers a promising approach for effective, long-acting pain control after surgery.