Investigation of radiation damage centers type and half-life produced by gamma radiation in some drugs and amino acids derivatives using EPR tecnique

This thesis consist of three parts. In the first part of this PhD work, radiation sensitiveness of compounds which used as active drug components while preparing neurological drugs investigated. Compounds were irradiated by gamma rays at 1, 5, 7,10,15,20,25 kGy irradiation doses. After that, the amounts and stability at room temperatures of the free radicals produced in the samples after irradiation were investigated by Electron Paramagnetic Resonance(EPR) spectroscopy. It is observed that the irradiated topiramate has singlet, gabapentin has doublet characteristic resonance peaks making simple the EPR spectra. Different functions were tried to elucidate experimental dose-response curves obtained for irradiated samples at different dose values and best functions describing the curves were determined. It can be concluded from dose-response curves that topiramat and gabapentin samples were saturated at approximately 10 kGy dose value. The samples were stored at room temperature for a year and the changes in the signals were examined, by this way the stabilities of the radical or radicals responsible from the resonance signals and their room temperature decay constants determined.In the second part, gamma irradiated amino acid derivatives of L-Glutamine single crystal was investigated by EPR. It is observed that, in general, the EPR spectrum have five and six much more characteristic resonance peaks responsible from complex EPR spectra. The radiation damage center in irradiated L-Glutamine single crystal was attributed to the CH2?HCOOH (? electron radical) radical. The interaction of this damage centre with ? proton of unpaired electron was found anisotropic, with methylene protons were found isotropic.In the third part of study, gamma irradiated amino acid derivatives of N-methyl-DL-alanine, L-glutamine t-butyl ester hydrochloride and D-(+)-galactosamine hydrochloride powder crystals investigated. The evaluation of spectra in together with simulation program show their CH3?H(COOH), CH2?HCOOH, CH?HOH radicals respectively.Key Words: EPR, Gamma Irradiation, Free Radical, Amino Acid Derivatives, Drug