Active Er-laser drug delivery using drug-impregnated gel for treatment of nail diseases

Abstract

Active Er-laser drug delivery under the nail plate using a drug-impregnated gel containing liquid methylene blue clusters is demonstrated for the first time. The effect of the agar-agar concentration in the gel and the gel plate thickness on the number of Er:YLF-laser pulses required for formation of a through microhole in the gel and in the nail plate with subsequent active drug delivery is discussed. The influence of the laser pulse energy, the gel plate thickness, and the external pressure applied to the gel on the rate of delivery of methylene blue under the nail plate through a single microhole in it is investigated. It is shown that with a laser pulse energy of 4.0 ± 0.1 mJ, the delivery rate can reach 0.024 ± 0.004 mg/pulse.

Fig. 1

Scheme of the experimental setup (a): 1 – Er:YLF-laser; 2 – collecting lens (F = 50 mm), 3 – gel plate; 4 –nail plate sample; 5 – paper substrate; 6 – glass slide; 7 – fastening screws; 8 – XZ-translator; 9 – digital USB-microscope “DTX 50” (Levenhuk, Inc., USA); 10 – Z-translator; 11 – computer; oscillogram of Er:YLF-laser radiation pulse (E = 4 mJ) (b).

Fig. 2

Photos of the MB-containing gel with 0.5%, 1%, 2% and 3% concentration of agar-agar (transmitted light).

Fig. 3

Dependence of the number of Er:YLF-laser pulses required for through microperforation of the gel (N_gp) on the concentration C_aa of agar-agar in it (a) and on the gel plate thickness h_g (b) (E = 4.0 mJ).

Fig. 4

Dependence of the delivery rate (V_MB) for gel with C_aa = 2% on laser pulse energy (E) at P = 1.3 kPa (a), on the gel plate thickness (h_g) at E = 4.0 mJ and P = 1.3 kPa (b), on the magnitude of the external pressure (P) applied to the gel for the extraction of the MB from it at E = 4.0 mJ and h_g = 500 μm (c).