The investigations deal with mass transfer in simulated biomedical systems. The modification of classical diffusion chamber, sequential unit (SU) system, imitated different biomedical setups, boundary conditions. The experiments simulated: diffusion chamber (also with two barriers), transport through the membrane to the blood stream, transport from the stent eluting drug simultaneously to the vessel cells and to the blood stream. The concentrations of substances and the relative mass increases/decreases for SU systems indicate that the order of the curves follows the order of mass transfer resistances. The strong dependence of mass transfer rates versus type of diffusing substance was confirmed. The calculated drug fluxes, diffusion coefficients, permeation coefficients are convergent with literature. Permeation coefficients for complex sequential systems can be estimated as parallel connexion of constituent coefficients. Experiments approved functionality of the SU for investigations in a simulated biomedical system. Obtained data were used for numerical verification.

Radiation therapy can be adopted for many cancers, and it can damage healthy tissues and often induces skin lesions (pain/skin irritation/itchiness/dryness/swelling/redness). Many factors influence the adverse effects of radiotherapy, such as radiation dosage, dose frequency and fractioning, the area of skin exposed to radiation and treatment length. In this paper, multiple emulsions with a nonsteroidal anti-inflammatory drug-NSAID (diclofenac) were developed and evaluated for effective topical treatment of skin lesions following anticancer therapy. Multiple emulsions with different drop sizes were prepared in a Couette- Taylor flow contactor. High encapsulation efficiency (> 90%) of diclofenac and high volume packing fraction of the internal droplets (0.54–0.96) were obtained. In addition, due to the presence of a polymer with adhesive properties - sodium carboxymethylcellulose, high emulsion stability (> 60 days) was achieved. The emulsions displayed properties of shearthinning fluids. The release study of diclofenac from a complex emulsion structure confirmed the possibility of modifying the release rates. The effectiveness of emulsion formulations was evaluated based on the viability tests of the fibroblast cell line irradiated with UV dose (15 J/m2) and then treated with the emulsion with diclofenac. The results showed that the multiple emulsion-based formulations might be appropriate carriers for the topical delivery of NSAID drugs.