Nonablative fractional laser as a tool to facilitate skin penetration of 5-aminolaevulinic acid with minimal skin disruption: a preliminary study.

ABSTRACT

BACKGROUND: Effective penetration of a photosensitizer is an essential step in photodynamic therapy (PDT). There have been trials of several methods, including laser treatment, to facilitate prompt and sufficiently deep transdermal drug delivery. OBJECTIVE: To evaluate the effects of nonablative fractional laser pretreatment on 5-aminolaevulinic acid (ALA) penetration of the skin. METHODS: Twelve treatment areas (1 × 1 cm(2)) on the backs of 10 healthy male subjects were mapped. Test areas received laser treatment followed by incubation with ALA. Laser treatment was performed with a 1550 nm fractional erbium glass laser, and the laser energy was set to 20 or 50 mJ with a spot density of 50 cm(-2). ALA incubation time was 30, 60 or 180 min. Porphyrin fluorescence was measured. RESULTS: Sites pretreated with nonablative fractional laser showed significantly increased porphyrin fluorescence compared with nonpretreated areas. Laser energy strength and ALA incubation time were positively correlated with ALA absorption. CONCLUSIONS: Nonablative fractional laser treatment effectively enhanced ALA skin penetration. Pretreatment with a nonablative fractional laser can be used for ALA-PDT to achieve higher ALA uptake and shortened ALA incubation times with minimal skin barrier disruption compared with ablative laser.