Bioadhesive films containing benzocaine: correlation between in vitro permeation and in vivo local anesthetic effect.
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.
de Araujo
Daniele Ribeiro
DR
Human and Natural Sciences Center, Federal University of ABC-UFABC, Santo André, SP, Brazil.
Padula
Cristina
C
Cereda
Cíntia Maria Saia
CM
Tófoli
Giovana Radomille
GR
Brito
Rui Barbosa
RB
de Paula
Eneida
E
Nicoli
Sara
S
Santi
Patrizia
P
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
D000779:Anesthetics, Local; D001566:Benzocaine