With technology now allowing for directly visualizing a peripheral nerve prior to injection, perineural nerve block, including brachial plexus nerve block, has become increasingly popular. The brachial plexus is a large, complex bundle of nerves (arising from the nerve roots C5-T1). A single injection of local anesthetic around the brachial plexus nerve bundle results in block of arm selleck chemical Seliciclib tissue innervated Inhibitors,research,lifescience,medical by selleck chem inhibitor several peripheral nerves. Several approaches to the brachial plexus blockade have been described (i.e., the axillary, infraclavicular,
supraclavicular, and interscalene) and each have advantages in certain situations. Stabilization of the needle for catheter insertion after brachial plexus blockade is localized and is a challenging aspect
of this technique . Brachial plexus blockade may require dispersion of a relatively large volume of bupivacaine in solution to accomplish blockade of the entire Inhibitors,research,lifescience,medical plexus. Complications may include infection, hematoma, vascular puncture, toxicity, injury, and total spinal anesthesia . After performing the block procedure, peripheral nerves may be damaged from prolonged contact with concentrated formulations [4, 5]. From a systemic standpoint, high doses of bupivacaine may be associated with a wide range of systemic complications, such as central nervous and cardiovascular effects . A formulation of bupivacaine that provides prolonged release of the active ingredient after a single administration Inhibitors,research,lifescience,medical would simplify pain management in the postoperative period and eliminate the undesired peak plasma concentrations as a result of Inhibitors,research,lifescience,medical excessively high concentrations and reduce the risk of local and systemic reactions . EXPAREL (bupivacaine liposome injectable suspension) is a sterile suspension of multivesicular liposomes using proprietary DepoFoam formulation technology to release bupivacaine over several days. EXPAREL, the proposed proprietary
name, was designed to provide prolonged analgesia for 72 hours after wound infiltration in patients . Although different liposomal formulations have been administered Inhibitors,research,lifescience,medical to humans without toxicity , the in vivo tolerability of liposomes continues to be investigated. AV-951 Our goal was to evaluate the potential local and systemic toxicity of EXPAREL after a bolus injection into the brachial plexus (i.e., a large, complex bundle of nerves in the shoulder). Specifically, the study was designed to assess whether EXPAREL did not produce nerve damage in the setting of peripheral nerve block by comparison with unencapsulated bupivacaine or saline control. 2. Materials and Methods 2.1. Materials 2.1.1. Description of DepoFoam Technology The DepoFoam drug-delivery system is a proprietary, injectable technology that provides a sustained release of therapeutic compounds. The DepoFoam system consists of multivesicular liposomes composed of hundreds to thousands of chambers per particle, resembling a “honeycomb-like” matrix .