Fractional laser-assisted drug delivery: Active filling of laser channels with pressure and vacuum alteration

TY - JOUR

T1 - Fractional laser-assisted drug delivery

T2 - Active filling of laser channels with pressure and vacuum alteration

AU - Erlendsson, Andrés M

AU - Doukas, Apostolos G

AU - Farinelli, William A

AU - Bhayana, Brijesh

AU - Anderson, R Rox

AU - Haedersdal, Merete

N1 - © 2015 Wiley Periodicals, Inc.

PY - 2016/2/1

Y1 - 2016/2/1

N2 - Background and Objective Ablative fractional laser (AFXL) is rapidly evolving as one of the foremost techniques for cutaneous drug delivery. While AFXL has effectively improved topical drug-induced clearance rates of actinic keratosis, treatment of basal cell carcinomas (BCCs) has been challenging, potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous deposition and delivery kinetics; (iii) biodistribution and diffusion pattern, estimated by mathematical simulation. Methods Franz diffusion chambers (FCs) were used to evaluate the PVP-technique, comparing passive (AFXL) and active (AFXL + PVP) channel filling. A fractional CO2-laser generated superficial (225 μm;17.5 mJ/channel) and deep (1200 μm; 130.5 mJ/channel) channels, and PVP was delivered as a 3-minutes cycle of 1 minute pressure (+1.0 atm), 1 minute vacuum (-1.0 atm), and 1 minute pressure (+1.0 atm). Filling of laser channels was visualized with a colored biomarker liquid (n = 12 FCs, n = 588 channels). Nuclear magnetic resonance quantified intracutaneous deposition of topically applied polyethylene glycol (PEG400) over time (10 minutes, 1 hour, and 4 hours), investigated with (n = 36 FCs) and without (n = 30 FCs) PVP-filling. Two-dimensional mathematical simulation was used to simulate intradermal biodistribution and diffusion at a depth of 1,000 μm. Results Active filling with application of PVP increased the number of filled laser channels. At a depth of 1,000 μm, filling increased from 44% (AFXL) to 94% with one PVP cycle (AFXL + PVP; P < 0.01). Active filling greatly enhanced intracutaneous deposition of PEG400, resulting in a rapid delivery six-folding uptake at 10 minutes (AFXL 54 μg/ml vs. AFXL + PVP 303 μg/ml, P < 0.01). AFXL alone generated an inhomogeneous uptake of PEG400, which greatly improved with active filling, resulting in a uniform uptake within the entire tissue. Conclusion Active filling with PVP secures filling of laser channels and induces a deeper, greater, more rapid delivery than conventional AFXL. This delivery technique has promise to improve treatment efficacy for medical treatments of dermally invasive lesions, such as BCCs.

AB - Background and Objective Ablative fractional laser (AFXL) is rapidly evolving as one of the foremost techniques for cutaneous drug delivery. While AFXL has effectively improved topical drug-induced clearance rates of actinic keratosis, treatment of basal cell carcinomas (BCCs) has been challenging, potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous deposition and delivery kinetics; (iii) biodistribution and diffusion pattern, estimated by mathematical simulation. Methods Franz diffusion chambers (FCs) were used to evaluate the PVP-technique, comparing passive (AFXL) and active (AFXL + PVP) channel filling. A fractional CO2-laser generated superficial (225 μm;17.5 mJ/channel) and deep (1200 μm; 130.5 mJ/channel) channels, and PVP was delivered as a 3-minutes cycle of 1 minute pressure (+1.0 atm), 1 minute vacuum (-1.0 atm), and 1 minute pressure (+1.0 atm). Filling of laser channels was visualized with a colored biomarker liquid (n = 12 FCs, n = 588 channels). Nuclear magnetic resonance quantified intracutaneous deposition of topically applied polyethylene glycol (PEG400) over time (10 minutes, 1 hour, and 4 hours), investigated with (n = 36 FCs) and without (n = 30 FCs) PVP-filling. Two-dimensional mathematical simulation was used to simulate intradermal biodistribution and diffusion at a depth of 1,000 μm. Results Active filling with application of PVP increased the number of filled laser channels. At a depth of 1,000 μm, filling increased from 44% (AFXL) to 94% with one PVP cycle (AFXL + PVP; P < 0.01). Active filling greatly enhanced intracutaneous deposition of PEG400, resulting in a rapid delivery six-folding uptake at 10 minutes (AFXL 54 μg/ml vs. AFXL + PVP 303 μg/ml, P < 0.01). AFXL alone generated an inhomogeneous uptake of PEG400, which greatly improved with active filling, resulting in a uniform uptake within the entire tissue. Conclusion Active filling with PVP secures filling of laser channels and induces a deeper, greater, more rapid delivery than conventional AFXL. This delivery technique has promise to improve treatment efficacy for medical treatments of dermally invasive lesions, such as BCCs.

KW - Administration, Cutaneous

KW - Animals

KW - Biomechanical Phenomena

KW - Diffusion

KW - Drug Delivery Systems

KW - Female

KW - Kinetics

KW - Lasers, Gas

KW - Polyethylene Glycols

KW - Pressure

KW - Skin

KW - Swine

KW - Vacuum

KW - Journal Article

U2 - 10.1002/lsm.22374

DO - 10.1002/lsm.22374

M3 - Journal article

C2 - 26280816

SN - 0196-8092

VL - 48

SP - 116

EP - 124

JO - Lasers in Surgery and Medicine

JF - Lasers in Surgery and Medicine

IS - 2

ER -