Spectroscopic investigations of novel pharmaceuticals: Stability and resonant interaction with laser beam

Abstract

This paper presents data about photophysics of two novel thio-hydantoins that exhibit promising pharmaceutical properties in multidrug resistance control. Time stability studies are necessary to establish the proper use of these compounds in different applications. As for their administration as drugs, it is imperative to know their shelf life, as well as storage conditions.At the same time, laser induced modified properties of the two new compounds are valuable to further investigate their specific interactions with other materials, including biological targets.The two new thio-hydantoins under generic names SZ-2 and SZ-7 were prepared as solutions in dimethyl sulfoxide at different concentrations, as well as in deionised water. For the stability assay they were kept in various light/temperature conditions up to 60days. The stability was estimates based on UV–vis absorption measurements.The samples in bulk shape were exposed different time intervals to laser radiation emitted at 266nm as the fourth harmonic of a Nd:YAG laser. The resonant interaction of the studied compounds with laser beams was analysed through spectroscopic methods UV–vis and FTIR absorption, as well as laser induced fluorescence spectroscopy.As for stability assay, only solutions kept in dark at 4°C have preserved the absorption characteristics, considering the cumulated measuring errors, less than one week.The vibrational changes that occur in their FTIR and modified fluorescence spectra upon laser beam exposure are also discussed.A result of the experimental analysis is that modifications are induced in molecular structures of the investigated compounds by resonant interaction with laser radiation. This fact evidences that the molecules are photoreactive and their characteristics might be shaped through controlled laser radiation exposure using appropriate protocols. This conclusion opens many opportunities both in the biomedical field, but also in other industrial activities involving the use of hydantoins.