title: Liposomal lidocaine gel for topical use at the oral mucosa: characterization, in vitro assays and in vivo anesthetic efficacy in humans.
abstract: OBJECTIVE
  To characterize liposomal-lidocaine formulations for topical use on oral mucosa and to compare their in vitro permeation and in vivo anesthetic efficacy with commercially available lidocaine formulations.
  
  
  METHODS
  Large unilamellar liposomes (400 nm) containing lidocaine were prepared using phosphatidylcholine, cholesterol, and α-tocoferol (4:3:0.07, w:w:w) and were characterized in terms of membrane/water partition coefficient, encapsulation efficiency, size, polydispersity, zeta potential, and in vitro release. In vitro permeation across pig palatal mucosa and in vivo topical anesthetic efficacy on the palatal mucosa in healthy volunteers (double-blinded cross-over, placebo controlled study) were performed. The following formulations were tested: liposome-encapsulated 5% lidocaine (Liposome-Lido5); liposome-encapsulated 2.5% lidocaine (Liposome-Lido2.5); 5% lidocaine ointment (Xylocaina®), and eutectic mixture of lidocaine and prilocaine 2.5% (EMLA®).
  
  
  RESULTS
  The Liposome-Lido5 and EMLA showed the best in vitro permeation parameters (flux and permeability coefficient) in comparison with Xylocaina and placebo groups, as well as the best in vivo topical anesthetic efficacy.
  
  
  CONCLUSIONS
  We successfully developed and characterized a liposome encapsulated 5% lidocaine gel. It could be considered an option to other topical anesthetic agents for oral mucosa.
authors.affiliation: Department of Physiological Sciences, Piracicaba Dental School, University of Campinas - UNICAMP , Piracicaba, São Paulo , Brazil .
authors.forename: Michelle
authors.initials: M
authors.lastname: Franz-Montan
authors.forename: Daniela
authors.initials: D
authors.lastname: Baroni
authors.forename: Giovana
authors.initials: G
authors.lastname: Brunetto
authors.forename: Viviane Roberta Vieira
authors.initials: VR
authors.lastname: Sobral
authors.forename: Camila Morais Gonçalves
authors.initials: CM
authors.lastname: da Silva
authors.forename: Paulo
authors.initials: P
authors.lastname: Venâncio
authors.forename: Patricia Wiziack
authors.initials: PW
authors.lastname: Zago
authors.forename: Cintia Maria Saia
authors.initials: CM
authors.lastname: Cereda
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Volpato
authors.forename: Daniele Ribeiro
authors.initials: DR
authors.lastname: de Araújo
authors.forename: Eneida
authors.initials: E
authors.lastname: de Paula
authors.forename: Francisco Carlos
authors.initials: FC
authors.lastname: Groppo
mesh_terms: D000287:Administration, Topical; D000293:Adolescent; D000328:Adult; D000779:Anesthetics, Local / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D004353:Drug Evaluation, Preclinical; D005260:Female; D005782:Gels; D006801:Humans; D007700:Kinetics; D008012:Lidocaine / Q000737:chemistry* / Q000378:metabolism; D008081:Liposomes; D008297:Male; D009061:Mouth Mucosa / Q000378:metabolism*; D010539:Permeability; D034421:Sus scrofa; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D008081:Liposomes; D008012:Lidocaine
keywords: Lidocaine; liposome; oral mucosa; topical anesthesia