Korean J Anesthesiol.  1999 Feb;36(2):305-310. 10.4097/kjae.1999.36.2.305.

Prolonged Regional Anesthesia with Lidocaine Microspheres by Using a Biodegradable Polymer

• Lim JO
• Park SS
• Baek WY

• KMID: 2091358
• DOI: http://doi.org/10.4097/kjae.1999.36.2.305

Abstract

BACKGROUND: Biodegradable microspheres are a useful method of drug delivery because they are both injectable and biodegradable. Previous work in our group has characterized implantable preparations of local anesthetics in pellets for prolonged regional anesthesia. In this paper we evaluated injectable suspensions of lidocaine-polymer microspheres for extended period of percutaneous sciatic nerve blockade in rats.
METHODS
Microspheres were prepared using poly (lactide-co-glycolide) loaded with 50 wt% lidocaine by a solvent evaporation method. In vitro release rate of lidocaine from microspheres was determined by high performance liquid chromatography (HPLC). Percutaneous blockade of the rat sciatic nerve was performed, and sensory blockade of the nerve was assessed using an analgesiometer.
RESULTS
Lidocaine was released in a controlled manner in vitro. In general 60% of the drug released in the first day, 80% in two days. Sciatic nerve blockade duration ranged from 8 to 12 hours. Incorporation of dexamethasone 0.05 wt% into the microspheres resulted in significant prolongation of block.
CONCLUSION
Prolonged percutaneous blockade of peripheral nerve is achieved using biodegradable polymeric lidocaine microspheres.

Keyword

Anesthesia, duration; Anesthetics, local, lidocaine; Microspheres, polymer

MeSH Terms

Anesthesia, Conduction*
Anesthetics, Local
Animals
Chromatography, Liquid
Dexamethasone
Lidocaine*
Microspheres*
Peripheral Nerves
Polymers*
Rats
Sciatic Nerve
Suspensions
Anesthetics, Local
Dexamethasone
Lidocaine
Polymers
Suspensions