Post-irradiation recovery time strongly influences fractional laser-facilitated skin absorption.
Int J Pharm
; 564: 48-58, 2019 Jun 10.
Article
em En
| MEDLINE
| ID: mdl-30999045
ABSTRACT
Fractional CO2 laser treatment has been used in some clinical trials to promote topical drug delivery. Currently, there is no standard for laser settings to achieve a feasible therapy. The cutaneous recovery following laser treatment and its influence on drug absorption have not been well explored. This study evaluated the kinetics of laser-treated skin-barrier restoration and drug permeation in nude mice. The skin recovery and observation of the process were characterized by transdermal water loss (TEWL), erythema measurement, gross appearance, optical microscopy, and scanning electron microscopy (SEM). The skin absorption of a lipophilic small permeant (tretinoin), a hydrophilic small permeant (acyclovir), and a large molecule (fluorescein isothiocyanate dextran 4â¯kDa, FD4) was examined in vitro using Franz cell. TEWL suggested that the laser-treated skin restored its barrier function at 16â¯h after irradiation. The fractional laser produced microchannels of about 150⯵m in diameter and 25⯵m in depth that were surrounded with thermal coagulation. The bright-field imaging indicated that the micropores were progressively closed during the recovery period but had not completely closed even after a 16-h recovery. The laser treatment led to a rapid tretinoin penetration across the skin immediately after irradiation, with a 5-fold enhancement compared to intact skin. This enhancement was gradually reduced following the increase of recovery time. Conversely, the acyclovir and FD4 permeation peaked at 1-2â¯h post-irradiation. The FD4 flux was even elevated as the recovery time increased. The reasons for this could have been the subsequent inflammation after laser exposure and the deficient tight junction (TJ) barrier. The confocal imaging demonstrated the perpendicular diffusion of rhodamine B and FD4 through microchannels immediately after laser exposure. The lateral diffusion from the microchannels was observed at 2â¯h post-irradiation. Our results revealed a time-dependent recovery of skin permeation. The time frame for applying the drugs after laser irradiation was dependent upon the permeants and their various physicochemical properties.
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Bases de dados:
MEDLINE
Assunto principal:
Absorção Cutânea
/
Sistemas de Liberação de Medicamentos
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Lasers
Limite:
Animals
Idioma:
En
Revista:
Int J Pharm
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Taiwan