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Polymeric Microneedle Array Fabrication by Photolithography
Published on: November 17, 2015
Local toxicity from local anesthetic polymeric microparticles.
J Brian McAlvin1, Gally Reznor, Sahadev A Shankarappa
1Department of Medicine, Medicine Critical Care Program, Children’s Hospital Boston, Harvard Medical School, Boston, MA 02115, USA.
Sustained-release local anesthetics like lidocaine and bupivacaine cause similar tissue injury, regardless of drug type or concentration. Intrinsic myotoxicity does not predict this injury, warranting caution near muscle and nerve.
Area of Science:
- Biomaterials Science
- Pharmacology
- Toxicology
Background:
- Local anesthetics delivered via sustained-release formulations can cause severe tissue injury.
- Variability in reporting such injuries necessitates standardized investigation.
- The intrinsic myotoxicity of encapsulated anesthetics is a key factor in tissue reaction.
Purpose of the Study:
- To investigate the influence of intrinsic myotoxicity of lidocaine (low) and bupivacaine (high) on tissue reaction in rats.
- To compare the myotoxicity and efficacy of different concentrations of lidocaine and bupivacaine in poly(lactic-co-glycolic) acid (PLGA) microspheres.
Main Methods:
- Cytotoxicity of lidocaine and bupivacaine was assessed in C2C12 myotubes.
- Rats received sciatic nerve blocks using 10% and 50% (w/w) lidocaine or bupivacaine PLGA microparticulate formulations.
- Nerve blockade effectiveness, myotoxicity scores, and drug release kinetics were evaluated.
Main Results:
- All microparticulate formulations induced myotoxicity in rats.
- The type of local anesthetic (lidocaine vs. bupivacaine) did not significantly alter myotoxicity severity.
- Median myotoxicity scores were comparable between 50% lidocaine and 50% bupivacaine formulations at 4 and 14 days.
Conclusions:
- Lidocaine and bupivacaine PLGA microspheres cause similar myotoxicity, irrespective of drug loading.
- Intrinsic myotoxicity of the anesthetic does not predict tissue injury from sustained-release formulations.
- Caution is advised when using these sustained-release anesthetic devices near muscle and nerve tissue.
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