title: Transdermal delivery of butamben using elastic and conventional liposomes.
abstract: Gel formulations containing the local anesthetic butamben (BTB) encapsulated in either conventional (BTBLUV) or elastic (BTBLUV-EL) liposomes were prepared and characterized, and then evaluated in terms of their skin permeability. Parameters measured included vesicle size and surface charge, BTB fluorescence anisotropy, encapsulation efficiency, partition coefficient and liposomal membrane organization. Encapsulation efficiencies and membrane/water partition coefficients were determined using a phase separation. The partition coefficients of the elastic and conventional formulations were 2025 ± 234 and 1136 ± 241, respectively. The sizes of the elastic and conventional liposomes did not change significantly (p > 0.05) following incorporation of the anesthetic. As expected, the elastic liposomes presented order parameters that were lower than those of the conventional liposomes, as determined by electron paramagnetic resonance with a 5-stearic acid nitroxide probe incorporated into the bilayer. After 8 h, the fluxes into the receiving solution (µg/cm(2)/h) were 6.95 ± 1.60 (10% BTB), 23.17 ± 6.09 (10% BTBLUV) and 29.93 ± 6.54 (10% BTBLUV-EL). The corresponding time lags (h) were 1.90 ± 0.48, 1.23 ± 0.28 and 1.57 ± 0.38, respectively. The permeability coefficients (10(-3 )cm/h) were 1.02 ± 0.23, 2.96 ± 0.77 and 4.14 ± 0.9, for 10% BTB, 10% BTBLUV and 10% BTBLUV-EL, respectively. The results demonstrate that anesthetic access through the skin can be considerably enhanced using liposomal gel formulations, compared to plain gel formulations.
authors.affiliation: Department of Biochemistry, Institute of Biology, State University of Campinas (UNICAMP), P.O. Box 6109, 13083-970, Campinas, São Paulo, Brazil. cscereda@gmail.com
authors.forename: Cintia Maria Saia
authors.initials: CM
authors.lastname: Cereda
authors.forename: Michelle
authors.initials: M
authors.lastname: Franz-Montan
authors.forename: Camila Morais Gonçalves
authors.initials: CM
authors.lastname: da Silva
authors.forename: Bruna Renata
authors.initials: BR
authors.lastname: Casadei
authors.forename: Cleyton Crepaldi
authors.initials: CC
authors.lastname: Domingues
authors.forename: Giovana Radomille
authors.initials: GR
authors.lastname: Tofoli
authors.forename: Daniele Ribeiro
authors.initials: DR
authors.lastname: de Araujo
authors.forename: Eneida
authors.initials: E
authors.lastname: de Paula
mesh_terms: D000279:Administration, Cutaneous; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D001566:Benzocaine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D004339:Drug Compounding; D004548:Elasticity; D005454:Fluorescence Polarization; D005782:Gels / Q000378:metabolism; D008081:Liposomes; D010316:Particle Size; D015203:Reproducibility of Results; D012869:Skin Absorption; D013552:Swine
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D008081:Liposomes; C004605:butamben; D001566:Benzocaine