Publications by authors named "Tadeusz W Hermann"

Abstract: The stability of aqueous and non-aqueous papaverine hydrochloride solutions exposed to the UV radiation is poor. In order to enhance its photo-stability suitable light absorbers may be used. There werefour photo-protectors considered in this work: 4-aminobenzoic acid, sodium benzoate, methyl 4-hydroxybenzoate and propyl 4-hydroxybenzoate, whose UV absorption spectra characteristics match to some extent with the UV spectrum of papaverine.

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The interactions of G-quadruplex DNA with two oxidation products of papaverine, 6a,12a-diazadibenzo-[a,g]fluorenylium derivative (1) and 2,3,9,10-tetramethoxy-12-oxo-12H-indolo[2,1-a]isoquinolinium cation (2) were investigated. Their activity against telomerase was assessed using the conventional telomeric repeat amplification protocol (TRAP) assay. Effect of TRAP buffer and oligonucleotide length on the DNA-binding affinity of 1 and 2 were also studied.

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HPCE methodology was modified to be used in kinetic experiments on photooxidation reactions of papaverine hydrochloride 1 and its oxidation products (papaverinol 2 and papaveraldine hydrochloride 3) chloroform solutions exposed to UV254 light in aerobic conditions. On photooxygenation of the above compounds is formed the final degradation product, a brown compound X 4, 2,3,9,10-tetramethoxy-12-oxo-12H-indolo[2,1-a]isoquinolinylim chloride. The rate of 4 formation from the above compounds can be given as 2>3>1>1 HCl.

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Background: Immediate release and modified release gliclazide formulation tablets are available on the market. We decided to measure the kinetics of gliclazide release from these tablets, and to propose our own technique for producing gliclazide matrix tablets, comparing their release kinetic profile with the gliclazide tablets available on the market.

Material/methods: A BP 2001 dissolution test was performed for selected gliclazide formulation tablets, and the water solubility of authentic gliclazide samples from different manufacturers was determined by UV spectrometry.

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The aggregation and DNA binding behavior of a new G-quadruplex selective ligand, 6a,12a-diazadibenzo-[a,g]fluorenylium derivative, was studied by UV-vis absorption and fluorescence spectroscopy. The formation of ligand aggregates with different spectral characteristics was observed at low and high concentration of NaCl, respectively. The ligand binds to G-quadruplex with much higher affinity than to single- and double-stranded DNA.

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The structure of the final degradation product formed in papaverine solutions in either water or chloroform was found to be a 2, 3, 9, 10-tetramethoxy-12-oxo-12H-indolo [2, 1-a] isoquinolinylium salt (a dibenzo [b, g] pyrrocolonium derivative). Its formation from papaverine oxidation products that is papaverinol, papaveraldine, and papaverine-N-oxide chloroform solutions under the influence of UV light, was investigated and possible reaction pathways are discussed.

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Papaverine hydrochloride, papaverinol, and papaveraldine chloroform solutions were exposed to UV light of 254 nm in atmospheric, aerobic and anaerobic (helium) conditions. The same degradation products appear (TLC) in the above papaverine hydrochloride chloroform solutions. However, the rate of papaverine hydrochloride degradation processes is enhanced as a function of oxygen pressure.

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In 1915 Gadamer published in this journal [1] a procedure for the synthesis of papaverinol 2 from papaverine 1 in excellent yield. However, he did not investigate the formation of a violet fluorescence produced upon crystallization of papaverinol 2 from ethanol. The compound responsible for this fluorescence was isolated and identified as the yet unknown quaternary ammonium ion 4, a 6a, 12a-diazadibenzo-[a, g]fluorenylium derivative.

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