Multivesicular liposomal bupivacaine at the sciatic nerve

Abstract

Clinical translation of sustained release formulations for local anesthetics has been limited by adverse tissue reaction. Exparel™ (DepoFoam bupivacaine) is a new liposomal local anesthetic formulation whose biocompatibility near nerve tissue is not well characterized. Exparel™ injection caused sciatic nerve blockade in rats lasting 240 minutes compared to 120 minutes for 0.5% (w/v) bupivacaine HCl and 210 minutes for 1.31% (w/v) bupivacaine HCl (same bupivacaine content as Exparel™). On histologic sections four days after injection, median inflammation scores in the Exparel™ group (2.5 of 4) were slightly higher than in groups treated with bupivacaine solutions (score 2). Myotoxicity scores in the Exparel™ group (2.5 of 6) were similar to in the 0.5% (w/v) bupivacaine HCl group (3), but significantly less than in the 1.31% (w/v) bupivacaine HCl group (5). After two weeks, inflammation from Exparel™ (score 2 of 6) was greater than from 0.5% (w/v) bupivacaine HCl (1) and similar to that from 1.31% (w/v) bupivacaine HCl (1). Myotoxicity in all three groups was not statistically significantly different. No neurotoxicity was detected in any group. Tissue reaction to Exparel™ was similar to that of 0.5% (w/v) bupivacaine HCl. Surveillance for local tissue injury will be important during future clinical evaluation.

Repeatable and adjustable on-demand sciatic nerve block with phototriggerable liposomes

“…Muscle tissue was processed with H&E staining, and nerve tissue was processed with toluidine blue staining (51,52). Irradiated tissues (with no particles injected) did not show inflammation or myotoxicity (Table 1).…”

“…Samples were treated with osmium tetroxide for postfixation and subsequently were stained with uranyl acetate, were dehydrated in graded ethanol solutions, and were infiltrated with propylene oxide/TAAB 812 Resin (TAAB Laboratories, Calleva Park, United Kingdom) mixtures. Tissue sections of 0.5 μm were stained with toluidine blue, followed by high-resolution light microscopy (6,52).…”

Nanoliposome encapsulated anesthetics for local anesthesia application

“…McAlvin et al [93] used Exparel (DepoFoam bupivacaine); a new liposomal local anesthetic preparation whose biocompatibility near nerve tissue has not been well characterized. The administration of Exparel resulted in sciatic nerve blockade in rats for 4 h as compared to 2 h for 0.5% (w/v) bupivacaine HCl and 3.5 h for 1.31% (w/v) bupivacaine HCl (same bupivacaine content as Exparel).…”

Pain Management Strategies in Hand Surgery

“…In the field of plastic surgery, Morales et al 76 Exparil's biocompatibility near nerve tissue is not well characterized but a few studies have began to look at the safety in such scenarios. McAlvin et al 77 injected…”