Introduction
Liposomes may provide for local, sustained-release formulations for improved therapeutic efficacy.
Liposomal Delivery of Bupivacaine to Prolong Analgesia
Bupivacaine is an anesthetic and has analgesic properties. IV or SC administration often results in a peak in plasma concentrations. Local infusion of bupivacaine via multilamellar vesicles allows for sustained local release and reduced systemic absorption.
Figure 1. A multilamellar vesicle (MLV) consists of multiple lipid bilayers surrounding the molecule. On the left is bupivacaine, the drug encapsulated inside.
Figure 2. Mice underwent a tail-flick protocol. Liposomal bupivacaine showed prolonged analgesia compared to free bupivacaine. From HY et al. J Pharm Pharmacol. 2002 Sep;54(9):1221-7.
Figure 3. Plasma concentrations of bupivacaine were measured and a steady, relatively low concentration was observed compared to free bupivacaine as IV and SC solution. Hence, IV liposome allows local delivery while maintaining low systemic distribution and plasma concentration. From HY et al. J Pharm Pharmacol. 2002 Sep;54(9):1221-7.