Local anesthetics are active ingredients that eliminate the perception and sensation of pain in a certain part of the body. Ever since their discovery, they have developed rapidly and are now widely used in all types of surgical procedures and subsequent postoperative patient care. Bupivacaine belongs to the group of amide local anesthetics and is one of the strongest and long-acting anesthetics. It is available commercialy as Marcain. Since 2011, a new liposomal form of bupivacaine (Exparel) has also been available. Liposomes act as a delivery system for various drugs and, due to the gradual release of the active ingredient, enable less frequent administration and prolonged action of an individual dose. The toxic effects of bupivacaine and other local anesthetics are known and fairly well studied. Due to their mechanism of action, they act primarily on organ systems that depend on ion channels and ion transfer. On the other hand, the toxic effects of the liposome form are not yet fully known. In the master's thesis, we determined the neurotoxic and myotoxic effects of both forms of bupivacaine and compared them with each other. We compared three different types of cytotoxicity: direct toxicity (determination of LDH enzyme activity), indirect cytotoxicity (determination of total protein content) and long-term effect of anesthetics on cells (Hoechst staining and cell counting). Both forms proved to be neurotoxic and myotoxic, and at the same dilutions, a slightly higher toxicity of the liposome form was observed. The differences are detectable only at the highest concentration, for lower concentrations both forms are similarly toxic. Myotoxicity was most pronounced in direct toxicity, with anesthetics being the most neurotoxic in long-term exposure testing. We can therefore conclude that local anesthetics are more acutely toxic to muscles but more pronounced chronic toxicity to nerve cells. There are no significant differences between the two forms that could affect clinical use.
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