Sciatic nerve blockade with lipid-protein-sugar particles containing bupivacaine

Area of Science:

• Biomaterials Science
• Pharmacology
• Nanotechnology

Background:

• Local anesthesia is crucial for surgical procedures.
• Prolonged anesthesia duration is often desired to improve patient comfort and reduce the need for repeated administrations.
• Current drug delivery systems have limitations in achieving sustained local anesthetic effects.

Purpose of the Study:

• To evaluate the efficacy of lipid-protein-sugar particles (LPSPs) for prolonged local anesthesia via percutaneous injection.
• To compare the anesthetic properties of LPSPs with established poly(lactic-co-glycolic) acid (PLGA) microspheres.

Main Methods:

• Bupivacaine-loaded LPSPs were formulated and characterized in vitro.
• Sciatic nerve blocks were performed in rats using bupivacaine-LPSPs.
• Sensory and motor blockade durations were assessed, along with systemic drug distribution via contralateral functional deficits.
• PLGA microspheres served as a comparative control.

Main Results:

• Optimized LPSPs (10% bupivacaine, 60% dipalmitoylphosphatidylcholine) had a diameter of 4.4±0.39 µm.
• LPSPs demonstrated sensory blockade durations comparable to PLGA microspheres (468±210 min vs. 706±344 min, p=0.08).
• Motor blockade duration was significantly shorter with LPSPs compared to PLGA microspheres (508±258 min vs. 1062±456 min, p=0.005).
• Minimal systemic toxicity was observed for both formulations.

Conclusions:

• LPSPs provide comparable sensory blockade duration to PLGA microspheres with lower drug loading.
• Shorter motor blockade with LPSPs may offer advantages in specific clinical scenarios.
• LPSPs are suitable for extended nerve blockade and may be useful for topical airway anesthesia due to their size and low density.