Transdermal drug delivery (TDD) is an increasingly important non-invasive method for administering active pharmaceutical ingredients (APIs) through the skin barrier, offering advantages such as improved therapeutic efficacy and reduced systemic side effects. As demand increases for patient-friendly and minimally invasive treatment options, TDD has attracted substantial attention in research and clinical practice. This review summarizes recent advances enhancing skin permeability through chemical enhancers (e.g., ethanol, fatty acids, terpenes), physical (e.g., iontophoresis, microneedles, sonophoresis), and nanotechnological methods (e.g., liposomes, ethosomes, solid lipid nanoparticles, and transferosomes). A comprehensive literature analysis, including scientific publications, regulatory guidelines, and patents, was conducted to identify innovative methods and materials used to overcome the barrier properties of the stratum corneum. Special emphasis was placed on in vitro, ex vivo, and in vivo evaluation techniques for such as Franz diffusion cells for assessing drug permeation and skin interactions. The findings highlight the importance of active physical methods, passive nanostructured systems, and chemical penetration enhancers. In conclusion, integrating multiple analytical techniques is essential for the rational design and optimization of effective transdermal drug delivery systems.

S-methylmethionine (SMM, also known as vitamin U) is a sulfur-containing vitamin-like compound that has been investigated since the 1940s for its gastroprotective and cytoprotective properties. Historically derived from observations of antiulcer activity in plant-derived foods, SMM has been studied in preclinical models and limited clinical settings for its multilevel pharmacological effects. This narrative review critically evaluates the available evidence on SMM’s pharmacological actions across organ systems, with explicit differentiation between preclinical and clinical data. It covers the most consistently reported gastroprotective and antiulcer effects, as well as antioxidant, anti-inflammatory, cytoprotective, and regenerative activities observed predominantly in preclinical studies. Particular attention is paid to organ-specific protection in the nervous system, liver, kidneys, lungs, skin, eyes, and oral tissues, although human evidence remains scarce. Proposed mechanisms are mediated primarily through suppression of oxidative stress, modulation of inflammatory and immune responses, maintenance of glutathione homeostasis, activation of ERK/NF-κB and Nrf2/Keap1 pathways, and regulation of methylation processes. Building on recent descriptive reviews, this work provides a structured critical synthesis that grades evidence quality, compares SMM with the structurally related methyl donor S-adenosylmethionine (SAMe), and analyses the translational and regulatory barriers that have prevented Western drug registration despite over 70 years of investigation. Despite a substantial preclinical evidence base and historical clinical observations, the level of evidence for many indications remains limited. Well-designed Phase II randomized controlled trials and innovative pharmaceutical formulations (especially topical and mucosal delivery systems) are urgently needed to translate preclinical promise into clinical benefits.

Introduction. Spray film-forming systems (SFFSs) are dosage forms that form an in situ film when sprayed. One of the key features of SFFSs is partial vapor permeability, a special case of occlusion. Various methods assess vapor permeability by determining the occlusion factor, but disparate approaches in studies prevent harmonizing results and identifying optimal parameters.Aim. Development of a methodology for determining the vapor permeability of spray film-forming systems, measuring the occlusion factor and studying the most significant factors affecting the accuracy of determining this characteristic.Materials and methods. Determination of vapor permeability was carried out using a special setup, consisting of a cell with water and a membrane fixed over it, on which the model composition was applied. Measurement cylinders of 25 ml (Russia) or penicillin vials with a smooth neck of 10 ml (Russia), membranes for filtration and dialysis (nylon, EPM.K, LLC RME "Technofilter", Russia), dialysis bags MEMBRA-CEL® (cellulose acetate, Viskase Companies, Inc., USA) and Sartopure® PP3 (polypropylene, Sartorius Stedim Biotech, Germany) were used. As sealants to isolate airflow around the membrane Parafilm M, C-silicone ZetaPlus L Intro Kit (Zhermack, Poland, Italy), hotmelt adhesive Master Hand (Union Source Со., Ltd., China), UV-curable material "UNIREST" (LLC "StomaDent", Russia) were used. Comparative analysis of materials was carried out on a model composition containing 0.5 % (m/o) Kollicoat® MAE 100P (BASF, Germany), 3 % (m/o) Soluplus® (BASF, Germany), 2 % (m/o) Kollisolv® PEG-400 (BASF, Germany), 70 % ethyl alcohol (SOJSC "Ferein", Belarus).Results and discussion. The combination of Parafilm M and the presented sealants showed high performance. Synthetic membrane occlusion factor for the model substance varied depending on the membrane type from 9.35 ± 3.58 to 16.86 ± 6.09, reflecting low-medium degree of occlusion.Conclusion. In this study optimized techniques for determining the vapor permeability for SFFS were developed. It was observed that rationalized membrane selection, consideration of the probability of moisture absorption by the membranes, method of sealing and cell calibrations, temperature and humidity levels, and vapor pressure were necessary.