Investigation of dielectric, conductivity and optical properties of drugs used in physical therapy and rehabi̇litation

In this thesis study, the dielectric, electrical conductivity, and optical properties of the drugs Dolgit, Melox, Paraflex, and Naprosyn, which are widely used in the field of physical therapy and rehabilitation, were comprehensively investigated through experimental methods. The study aims to evaluate the interactions of these drugs with electromagnetic radiation not only from a pharmacological perspective but also from photonic and biomedical engineering viewpoints. During the experimental process, the drugs were prepared as homogeneous solutions in appropriate solvents, and absorbance and transmittance spectra were obtained using UV–Vis spectroscopy. The acquired optical data were analyzed using the Beer–Lambert law, and the molar extinction coefficients and absorption band edges were calculated. A strong inverse relationship between the optical band gap and the refractive index was identified, and it was observed that the Herve–Vandamme and Reddy models yield more physically meaningful and balanced results for organic molecular systems. Due to having the lowest band gap, the Melox drug exhibited the highest refractive index and the strongest dielectric response. Measurements performed under UV irradiation revealed that Melox, in particular, displays wavelength-sensitive photonic behavior. While photodegradation effects became dominant under 254 nm UV irradiation, band gap narrowing and controlled modulation of the refractive index were observed under 365 and 400 nm UV light. The obtained results demonstrate that the investigated drugs are potential candidate materials for biomedical photonic applications, UV-based therapies, and light-activated systems. Keywords: Physical therapy, rehabilitation, dielectric, conductivity, optics, biomedical.