Method: The following were used as controls: unillamelar liposomal suspension, multillamelar liposomal suspension and 0.9% NaCl solution. All anesthetic formulations were injected in the right side and the respective controls in the left side. Total of 30 rats (10 animals per group) received 0.1mL of the anesthetic formulations near the infraorbital foramen. The duration of anesthesia was assessed by upper lip pinching every 5 minutes
Result: Data were submitted to Log-Rank, Kruskal-Wallis, Student-Newman-Keuls and Friedman tests (a= 5%). Prilo-Fely presented longer anesthesia duration than Prilo-LUV (p<0.05); Prilo-MLV did not differ from the others (p>0.05). Prilo-Fely promoted higher anesthesia success (p<0.05) than Prilo-LUV and Prilo-MLV, with no difference between these two formulations (p>0.05).
Conclusion: It can be concluded that the encapsulation of prilocaine in unillamelar and multillamelar liposomes provided lower anesthetic efficacy when compared to prilocaine with feypressin in infraorbital nerve block (IONB).