Anesthetic effcacy of 3% prilocaine unilamelar and multilamelar liposomal formulation in infraorbital and inferior alveolar nerve blocks and subcutaneous infiltration in surgical wound, in rats

Author(s)

Fabiana Pinchetti Nolasco

• Document type: Master's Dissertation
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2012-02-28

Examining board members

Francisco Carlos Groppo; Carina Denny; Juliana Cama Remacciato

• Advisor: Maria Cristina Volpato; Francisco Carlos Groppo

Abstract

The present study assessed the anesthetic efficacy of the following formulations: 3% prilocaine with 0.03 UI/mL felypressin (Prilo-Fely), 3% prilocaine encapsulated in unillamellar liposomes (Prilo-LUV, 4 mM lipid concentration) and 3% prilocaine encapsulated in multillamelar liposomes (Prilo-MLV, 8 mM lipid concentration) in three models, in rats: infraorbital nerve block (IONB), inferior alveolar nerve block (IANB), and subcutaneous infiltration in surgical wound (SISW). The following were used as controls: unillamelar liposomal suspension, multillamelar liposomal suspension and 0.9% NaCl solution. For IONB and IANB the anesthetic formulations were injected in the right side and the respective controls in the left side. For IONB, 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. For IANB, 45 rats (15 animals per group) received 0.2mL of the anesthetic formulations near the right mandibular foramen. The success, onset and duration of pulpal anesthesia were assessed by electric pulp tester. For SISW, 36 animals (6 animals per group) were submitted to incision in the right hind paw and 24h after they received 0.1mL of the formulations in both hind paws (with and without incision). Anesthesia was evaluated with von Frey anesthesiometer. Data were submitted to Log-Rank, Kruskal-Wallis, Student-Newman-Keuls and Friedman tests (?= 5%). For IONB 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). For IANB Prilo-Fely provided higher success and duration of anesthesia than the liposomal formulations (p<0.05); Prilo-MLV presented higher anesthesia success than Prilo-LUV (p<0.05), but did not differ from the latter concerning anesthesia duration (p>0.05). No differences among the formulations were observed for BNAI anesthesia onset (p>0.05). For SISW in the hypernociceptive paws, Prilo-Fely provided longer anesthesia duration than Prilo-LUV and Prilo-MLV (p<0.05), with no difference between these two formulations (p>0.05); in the non hypernociceptive paws no differences were observed among the formulations (p>0.05). In both conditions, with and without hypernociception, Prilo-Fely presented higher anesthesia success (p<0.05) than Prilo-LUV e Prilo-MLV, whith no difference between these two formulations (p>0.05). 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 the evaluated models (AU)

• FAPESP's process: 09/11797-1 - Anesthetic eficacy of uni and multi-lamellar prilocaine formulations in infra-orbital and inferior alveolar nerves block and in wound healing, in rats.
• Grantee: Fabiana Pinchetti Nolasco
• Support Opportunities: Scholarships in Brazil - Master