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Effect of microwave power on EPR spectra of thermally sterilized eucerinum anhydricum

Ramos P., Pepliński P., Pilawa B.

Nukleonika

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2015

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Vol. 60, No. 3, part 1

439--442

EN

Free radicals formed during thermal sterilization of eucerinum anhydricum – the pharmaceutical base were examined by an X-band (9.3 GHz) spectrometer. Eucerinum anhydricum was sterilized at different physical conditions according to the Polish Pharmacopeia norms. The samples were heated at temperatures: 160°C (120 min), 170°C (60 min), and 180°C (30 min). The aim of this study is to compare free radical concentration and effect of microwave power on EPR spectra of eucerinum anhydricum base thermally sterilized at different temperatures and periods of time. The effect of time storage on the free radicals in the heated samples was tested. Free radical concentrations in the sample stored 15 min strongly decreased with the increasing of sterilization temperature, probably as the result of recombination. Storage caused strong decrease of free radical concentrations in the samples, probably as the result of interactions with oxygen. It was observed to be independent of sterilization conditions from 2 days of storage and longer. Because of the lowest free radical concentration, for eucerinum anhydricum thermal sterilization at 180°C for 30 min is recommended. The sterilized samples should be stored at inert atmosphere without oxygen molecules. Fast spin-lattice relaxation processes existed in sterilized eucerinum anhydricum. The character of changes of amplitudes and linewidths of EPR lines with increasing of microwave power was the same for different storage times. The parameters of thermal sterilization and storage time influenced free radical concentration in eucerinum anhydricum, but magnetic spin-lattice interactions were unchanged. The usefulness of EPR spectroscopy in optimization of thermal sterilization process of eucerinum anhydricum was confirmed.

2

Effect of microwave power on EPR spectra of natural and synthetic dental biocompatible materials

Adamczyk J., Ramos P., Pilawa B.

Nukleonika

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2015

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Vol. 60, No. 3, part 1

449--453

EN

Paramagnetic centers in the two exemplary synthetic and natural dental biocompatible materials applied in implantology were examined by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. The EPR spectra were measured in the range of microwave power 2.2–70 mW. The aims of this work were to compare paramagnetic centers concentrations in different dental biocompatible materials and to determine the effect of microwave power on parameters of their EPR spectra. It is the very fi rst and innovatory examination of paramagnetic centers in these materials. It was pointed out that paramagnetic centers existed in both natural (~1018 spin/g) and synthetic (~1019 spin/g) dental biocompatible materials, but the lower free radical concentration characterized the natural sample. Continuous microwave saturation of EPR spectra indicated that faster spin-lattice relaxation processes existed in synthetic dental biocompatible materials than in natural material. Linewidths (ΔBpp) of the EPR spectra of the natural dental material slightly increased for the higher microwave powers. Such effect was not observed for the synthetic material. The broad EPR lines (ΔBpp): 2.4 mT, 3.9 mT, were measured for the natural and synthetic dental materials, respectively. Probably strong dipolar interactions between paramagnetic centers in the studied samples may be responsible for their line broadening. EPR spectroscopy is the useful experimental method in the examination of paramagnetic centers in dental biocompatible materials.

3

Effect of storage time on microwave saturation of EPR spectra of thermally sterilized streptomycin and its practical applications

Ramos P., Pilawa B., Bernaś M.

Journal of Medical Informatics & Technologies

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2010

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Vol. 15

185--191

EN

Electron paramagnetic resonance spectroscopy at X-band (9.3 GHz) is used as the tool of optimalization of storage of thermally sterilized aminoglycoside antibiotic - streptomycin. Thermal sterilization at different conditions was performed according to the norms. Changes in free radicals system of this drug during storage after sterilization were detected. Lineshape analysis and microwave saturation of EPR spectra were done. Free radical concentrations were determined. Microwave saturation EPR analysis is proposed as useful method to determine the best conditions of storage of sterilized drugs.

4

Influence of oxygen O2 on microwave saturation of EPR lines of plants carbonized at 650°c and potential application in medicine

Pilawa B., Bartłomiejczyk S., Krzesińska M., Pusz S., Zachariasz J., Wałach W.

Engineering of Biomaterials

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2008

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Vol. 11, no. 73

9-11

EN

Electron paramagnetic resonance spectroscopy (EPR) was used to examination of spin-lattice relaxation in vascular plants carbonized at 650°C. Application of EPR method of continuous microwave signal saturation in medicine was proposed. The first derivative EPR spectra of pyrolysed bamboo and yucca were measured for samples in air and in vacuum. Influence of microwave power in the range 0.7-100 mW on amplitudes of EPR lines were evaluated. It was stated that amplitudes of the studied carbon materials increase with increasing of microwave power in the studied range. Saturation of EPR lines was not observed, so fast spin-lattice relaxation processes exist in the analyzed materials. Changes of EPR amplitudes for samples in air were slower than for evacuated samples. This effect may be used for determination of oxygen contents in the biological cells cultures and for analysis of optimal parameters of photodynamic therapy of cancer.