• Cintia Maria Saia Cereda, Giovana Radomille Tofoli, Luiz Gabriel Maturana, Amauri Pierucci, Lazaro Alessandro Soares Nunes, Michelle Franz-Montan, Alexandre Leite Rodrigues de Oliveira, Sarah Arana, Daniele Ribeiro de Araujo, and Eneida de Paula.
• Department of Biochemistry, Institute of Biology, State University of Campinas, SP, Brazil. cscereda@gmail.com
• Anesth. Analg.. 2012 Nov 1;115(5):1234-41.

BackgroundBupivacaine (BVC) and ropivacaine (RVC) are local anesthetics widely used in surgical procedures. In previous studies, inclusion complexes of BVC or RVC in hydroxypropyl-β-cyclodextrin (HP-β-CD) increased differential nervous blockade, compared to the plain anesthetic solutions. In this study we evaluated the local neural and muscular toxicity of these new formulations containing 0.5% BVC or RVC complexed with HP-β-CD (BVC(HP-β-CD) and RVC(HP-β-CD)).MethodsSchwann cell viability was assessed by determination of mitochondrial dehydrogenase activity, and histopathological evaluation of the rat sciatic nerve was used to identify local neurotoxic effects (48 hours and 7 days after the treatments). Evaluations of serum creatine kinase levels and the histopathology of rat gastrocnemius muscle (48 hours after treatment) were also performed.ResultsSchwann cell toxicity evaluations revealed no significant differences between complexed and plain local anesthetic formulations. However, use of the complexed local anesthetics reduced serum creatine kinase levels 5.5-fold, relative to the plain formulations. The differences were significant at P < 0.05 (BVC) and P < 0.01 (RVC). The histopathological muscle evaluation showed that differences between groups treated with local anesthetics (BVC or RVC) and their respective complexed formulations (BVC(HP-β-CD) or RVC(HP-β-CD)) were significant (P < 0.05).ConclusionsWe concluded that the new formulations presented a lower myotoxicity and a similar cytotoxic effect when compared to plain local anesthetic solutions.

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