Development of a method for assessing the depth of penetration of ethosomes with methylene blue into the skin during application and photodynamic exposure

Abstract

A wide range of literature sources report on the potential benefits of transdermal drug delivery. Among these advantages, the following are distinguished – minimal injury, reduction of side effects, and prevention of degradation or metabolism in the gastrointestinal tract or liver. However, transdermal delivery of most molecules often excludes due to the barrier function of the skin, which prevents the penetration of exogenous substances. To overcome this barrier and increase skin absorption, ethosomal complexes use, by means penetration into the deep layers of the skin and/or systemic circulation is possible. This work devotes to the development of a non-invasive method for assessing the depth of penetration by ethosomes with methylene blue (MB) into the skin during application and photodynamic exposure. MB as photosensitizer (PS) was chosen, since there are a sufficient number of publications on its positive effect on the restoration of the cell’s respiratory chain of various organs and therefore the restoration of their metabolism. Besides MB has proven to be an effective PS, destructed pathogenic microbes and viruses, including SARS-CoV-2. However, for more effective Covid-19 therapy and antibiotic-resistant microbial diseases, the penetration of MB into the vascular system of the epidermis or mucous tissue is required. Nowadays, the existing methods for assessing the penetration depth of PS are time consuming and require the use of animal skin or model samples. The LESA-01 BIOSPEC system with specially designed optical adapters that allow assessing the drug fluorescence intensity on skin surface and at a depth of up to 2 mm in the investigation was used.