The changes in absorption spectra of aqueous solutions of modern chlorine-containing photosensitizing preparations "Revixan" (Areal, Russia) and "Chloderm" (Chloderm, Russia) depending on the intensity of LED radiation with wavelength of 656 ± 10 nm and exposure time were studied in spectral range 600-700 nm. The parameters of the CIE Lab color model of the image of "Revixan" aqueous solution before and after LED exposure were investigated. The changes in absorption spectra of aqueous solutions of methylene blue with different initial concentrations arising after exposure to LED radiation with intensity of 180 ± 20 mW/cm2 were studied in the spectral range 400-900 nm. It was shown that the impact of LED radiation changes the absorption spectra of the studied preparations and increases the parameter L (lightness) of the CIE Lab color model for "Revixan". An increase in the LED radiation intensity and exposure time leads to a decrease in absorption for "Revixan" and "Chloderm" in spectral range 600-700 nm and to a shift of the peaks of absorption bands lying in this range towards a longer wavelength. The impact of LED radiation on aqueous solutions of methylene blue leads to a decrease in their absorption in spectral range 400-900 nm.

For the first time, the possibility of a dual-stage active laser delivery of a modern chlorin-containing photodynamic preparation under the nail plate for photodynamic therapy of onychomycosis was investigated and demonstrated. The extinction spectra of the photodynamic preparation Revixan (Areal Ltd., Russia) were investigated at different temperatures, as well as before and after exposure to Er:YLF-laser radiation with a wavelength of 2810 nm and photodynamic LED radiation with a wavelength of 656 ± 10 nm. It is shown that after heating and laser exposure, the amount of monomers in the chlorin-containing photodynamic preparation increases, and after photodynamic exposure decreases, which can affect the effectiveness of photodynamic therapy of onychomycosis.