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...
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 percutaneous sciatic nerve block in rats.
Methods Microspheres were prepared using poly(lactide-co-glycolide) loaded with 50% wt % lidocaine by a solvent evaporation method. the in vitro rate of release of lidocaine from microspheres was determined by HPLC. Percutaneous blockade of the rat sciatic nerve was performed, and sensory blockade of the nerve were assessed using an analgesiometer.
Results Lidocaine was released in controlled manner in vitro. In general, 60% of the drug released in the first day, 80% two days. Sciatic nerve blockade duration ranged from 8 to 18 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.