Fractional CO₂ laser‐assisted drug delivery

Abstract

Background and Objectives: Ablative fractional resurfacing (AFR) creates vertical channels that might assist the delivery of topically applied drugs into skin. The purpose of this study was to evaluate drug delivery by CO 2 laser AFR using methyl 5-aminolevulinate (MAL), a porphyrin precursor, as a test drug. Materials and Methods: Two Yorkshire swine were treated with single-hole CO 2 laser AFR and subsequent topical application of MAL (Metvix 1 , Photocure ASA, Oslo, Norway), placebo cream and no drug. MAL-induced porphyrin fluorescence was measured by fluorescence microscopy at skin depths down to 1,800 mm. AFR was performed with a 10.6 mm wavelength prototype CO 2 laser, using stacked single pulses of 3 millisecond and 91.6 mJ per pulse. Results: AFR created cone-shaped channels of approximately 300 mm diameter and 1,850 mm depth that were surrounded by a 70 mm thin layer of thermally coagulated dermis. There was no porphyrin fluorescence in placebo cream or untreated skin sites. AFR followed by MAL application enhanced drug delivery with significantly higher porphyrin fluorescence of hair follicles (P<0.0011) and dermis (P<0.0433) versus MAL alone at skin depths of 120, 500, 1,000, 1,500, and 1,800 mm. AFR before MAL application also enhanced skin surface (epidermal) porphyrin fluorescence. Radial diffusion of MAL from the laser-created channels into surrounding dermis was evidenced by uniform porphyrin fluorescence up to 1,500 mm from the holes (1,000, 1,800 mm depths). Skin massage after MAL application did not affect MAL-induced porphyrin fluorescence after AFR. Conclusions: Ablative fractional laser treatment facilitates delivery of topical MAL deeply into the skin. For the conditions of this study, laser channels approximately 3 mm apart followed by MAL application could produce porphyrins throughout essentially the entire skin. AFR appears to be a clinically practical means for enhancing uptake of MAL, a photodynamic therapy drug, and presumably many other topical skin medications. Lasers Surg.

The fractional laser‐induced coagulation zone characterized over time by laser scanning confocal microscopy—A proof of concept study

“…Ablative fractional laser (AFXL) is one of several techniques to enhance topical drug uptake in skin [1,2]. Stratum corneum is a barrier for topical drug uptake [3,4].…”

Local Anesthesia for Cosmetic Procedures

“…Narrow but deep vertical channels of ablation into skin created by fractional CO2 laser were used to successfully deliver a drug, methyl 5-aminolevulinate (MAL) to a uniform depth into skin. 13 The absoption was uniform and full thickness indicating drug delivery from lateral walls of the tunnel. Currently trials are under progress to use this method to deliver local anesthetic agent to skin.…”

Laser Assisted Drug and Cosmeceutical Delivery System of the Skin

“…This increase is not permanently proportional, because the maximal tissue concentration can be limited. 10,11,12 Clinically the density of the spots is closely related to the risk of complication and the optimization for proper amount of delivery is very important.…”