title: Bioadhesive films containing benzocaine: correlation between in vitro permeation and in vivo local anesthetic effect.
abstract: OBJECTIVE
  The aim of this work was to develop anesthetic bioadhesive films containing benzocaine and study their in vitro skin permeation and in vivo performance, in comparison with commercial formulations.
  
  
  METHODS
  Films containing 3% and 5% w/w of benzocaine were prepared and characterized by weight, drug content, thickness and morphology. In vitro permeation assays were performed in vertical diffusion cells using full-thickness pig ear skin as barrier. Intensity and duration of analgesia were evaluated in rats by tail-flick test, and skin histological analysis was carried out.
  
  
  RESULTS
  Tail-flick test showed that the duration of benzocaine-induced analgesia was significantly prolonged with the films compared to commercial creams, in agreement with the higher in vitro permeation. Histological analysis of the rat tail skin did not reveal morphological tissue changes nor cell infiltration signs after application of the commercial creams or films.
  
  
  CONCLUSIONS
  Results from our study indicate that the films developed in this work can be considered as innovative dermal/transdermal therapeutic systems for benzocaine local delivery.
authors.affiliation: Human and Natural Sciences Center, Federal University of ABC-UFABC, Santo André, SP, Brazil.
authors.forename: Daniele Ribeiro
authors.initials: DR
authors.lastname: de Araujo
authors.forename: Cristina
authors.initials: C
authors.lastname: Padula
authors.forename: Cíntia Maria Saia
authors.initials: CM
authors.lastname: Cereda
authors.forename: Giovana Radomille
authors.initials: GR
authors.lastname: Tófoli
authors.forename: Rui Barbosa
authors.initials: RB
authors.lastname: Brito
authors.forename: Eneida
authors.initials: E
authors.lastname: de Paula
authors.forename: Sara
authors.initials: S
authors.lastname: Nicoli
authors.forename: Patrizia
authors.initials: P
authors.lastname: Santi
mesh_terms: D000279:Administration, Cutaneous; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics* / Q000494:pharmacology*; D000818:Animals; D001566:Benzocaine / Q000493:pharmacokinetics* / Q000494:pharmacology*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004355:Drug Stability; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012867:Skin / Q000187:drug effects* / Q000378:metabolism; D012869:Skin Absorption; D013552:Swine
chemical_list: D000779:Anesthetics, Local; D001566:Benzocaine