Long-acting local anesthetics (LA) are used in different anesthesia practices, but particularly for surgical procedures. Ropivacaine (RVC) is a new long-acting LA that has been in focus during the last decade because of its increased cardiovascular safety, when compared to bupivacaine. Delivery of LA in cyclodextrins has been investigated as a way to increase the therapeutic index and half-life of those drugs. Cyclodextrins are cyclic oligosaccharides with a somewhat lipophilic central cavity that is able to form inclusion complexes with guest molecules. Here we report the in vivo evaluation of an inclusion complex formed between ropivacaine and hydroxypropyl-beta-cyclodextrin (HP-b-CD). The complex was obtained by mixing appropriate amounts of HP-b-CD and ropivacaine to a final 1:1 molar ratio, under agitation (for 6 h, at room temperature), and it was spray-dried for further use. The solid complexes were suspended in HEPES buffer (20 mM plus 150mM NaCl, pH 7.4). The anesthetic effect of this new RVC formulation was compared to that of RVC solution, in a rat infraorbital nerve-blockade model; three LA concentrations were used in the experiments: 0.125, 0.25 and 0.5%. The results show that the RVC:HP-b-CD complex improved the total anesthetic effect (54.5%, 53.3% and 20.0%) and the time for recovery (42.9%, 44.4% and 18.8%), respectively, for the 0.125, 0.25 and 0.5% doses, in comparison to RVC solutions of equivalent concentrations (p<0.001 - Mann Whitney test). This enhancement in the nonciceptive effect with RVC:HP-b-CD is probably due to the increased amount of RVC available (water soluble) in the site of injection, mainly in the sub-clinical (0.125 and 0.25%) doses. Indeed, our results have shown that the intensity of the total anesthetic effect for 0.125% RVC:HP-b-CD was higher than that of 0.25% RVC (p< 0.01-Mann Whitney test). In conclusion, we suggest that complexation with HP-b-CD is a good alternative for the development of more effective long-acting RVC formulations, allowing the use of lower LA doses in order to reach the same anesthetic effects of 0.5% RVC solution. Supported by CAPES.