Update of Ablative Fractionated Lasers to Enhance Cutaneous Topical Drug Delivery

Abstract

Ablative fractional lasers (AFXL) enhance uptake of therapeutics and this newly emerging field is called laser-assisted drug delivery (LAD). This new science has emerged over the past decade and is finding its way into clinical practice. LAD is poised to change how medicine delivers drugs. Topical and systemic application of pharmaceutical agents for therapeutic effect is an integral part of medicine. With topical therapy, the stratum corneum barrier of the skin impairs the ability of drugs to enter the body. The purpose of LAD is to alter the stratum corneum, epidermis, and dermis to facilitate increased penetration of a drug, device, or cell to its respected target. AFXL represents an innovative, non-invasive strategy to overcome the epidermal barrier. LAD employs three steps: (1) breakdown of the skin barrier with a laser, (2) optional use a laser for a therapeutic effect, (3) delivery of the medicine through laser channels to further enhance the therapeutic effect. The advantages of using lasers for drug delivery include the ease of accessibility, the non-invasive aspect, and its effectiveness. By changing the laser settings, one may use LAD to have a drug remain locally within the skin or to have systemic delivery. Many drugs are not intended for use in the dermis and so it has yet to be determined which drugs are appropriate for this technique. It appears this developing technology has the ability to be a new delivery system for both localized and systemic delivery of drugs, cells, and other molecules. With responsible development AFXL-assisted drug delivery may become a new important part of medicine.

Keywords: Delivery; Drug; Energy device; Laser; Systematic.

Fig. 1

H&E-stained histology 3 h after AFXL CO₂ laser exposure (50 mJ/microbeam) of porcine skin in vivo, showing a microscopic ablation zone extending to the mid-dermis. A cuff of coagulated tissue surrounds the laser channel, which is filled with a protein transudate. Such protein transudate is typically absent immediately after CO₂ laser exposure and it is unclear how it affects drug delivery

Fig. 2

Before (a) and 6 months after (b) AFXL, a series of CO₂ laser-assisted delivery of topical poly-l-lactic acid for an atrophic surgical scar. Thereafter, two treatments of AFXL-assisted delivery of topical poly-l-lactic acid decreased the atrophy and visible depression of the scar as well as the overall cosmetic appearance

Fig. 3

Before (a) and 6 months after (b) AFXL, a series of CO₂ laser-assisted delivery of topical triamcinolone acetonide for a hypertrophic burn scar. Treatment began 5 years after the burn. Three non-ablative fractional treatments were initially administered with mild improvement. Thereafter, two treatments with AFXL (20 mJ at 10% density)-assisted delivery of topical triamcinolone acetonide led to impressive decrease in hypertrophy, improvement of dyschromia, and increased range of motion