Background and aims: LASSBio-1822 is a new N-acylhydrazone (NAH). Due to the diversity of biological actions of NAHs in this work our aim was to investigate the antinociceptive potential of the new molecule LASSBio-1822. 
Methods: Female Swiss Webster mice (22-25 g, n=4-6) were treated orally with LASSBio-1822 (0.003-0.3 mg/kg), morphine (2.5 mg/kg) or vehicle. Antinociceptive effects were evaluated in chemical (formalin-, glutamate- or capsaicin-induced licking) or thermal (hot plate, HP) models. Area under the curve (AUC) was calculated in Prism Software 5.0. Statistical analysis was performed by ANOVA/Bonferroni's post-test. Protocols for animal use received number #DFBCICB015-04/16. 
Results: In chemical models, 0.3 mg/kg significantly inhibited in 38.4% and 46.7% the 1st and 2nd phases of formalin-induced licking, respectively, and in 63.8% and 82.5% the capsaicin- and glutamate-induced nociception, respectively. All doses increased, in a dose dependent manner, the AUC (in HP) in 308%, 583% and 1053%, for 0.003, 0.03 and 0.3 mg/kg, respectively when compared to vehicle-treated group. The antinociceptive effect was also significant even when compared with morphine (which presented an increase of 76%).
Conclusions: Our data indicate that LASSBio-1822 demonstrated a significant antinociceptive effect even when compared with morphine and can be suggested as a promising prototype for the development of a new analgesic drug.
Acknowledgements: Alan Minho (Technical assistance), Instituto Vital Brazil (animal donation)
Financial support: CNPq (grant and fellowship to CAMF PDF), CAPES (fellowship to DCS), FAPERJ (grant and fellowship to CAMF, PDF)

A NEW N-ACYLHYDRAZONE AS A POTENTIAL ANTINOCICEPTIVE AGENT