Local anesthetic combined with capsaicin:hydroxypropyl-beta-cyclodextrin inclusion complex to selective increase the anesthetic potency

Abstract

Local anesthetics are often used in medical and dental practice when it is necessary to numb parts of the body. Despite all clinical demand, local anesthetics does not allow selective blockade of nociceptive fibers. And furthermore fail to anesthesia procedures as inflamed areas. In fact, it continues to search for local anesthetics agents with long duration, low systemic toxicity and motor blockade.The local anesthetic mepivacaine is in the amino amide family, mainly used in dentistry, and has an intermediate duration of anesthesia. Capsaicin is a poorly water soluble compound, extracted from chili peppers, which have analgesic action and allows the opening of TRPV1 channels, only expressed in nociceptive fibers. Recently, it was reported that the application of local anesthetic followed by capsaicin leads to a selective increase in sensory blockade in rats due to easy entry of local anesthetics in nociceptive fibers (Gerner et al., 2008).In this study, we intend to develop, characterize and evaluate the effectiveness of inclusion complex of capsaicin:cyclodextrin associated to mepivacaine. Through this approach, it is expected to improve the solubility of capsaicin, developing a single dose formulation with better sensory blocking and reduced motor blockade.