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Open access

Şerban Andrei Gâz Florea, Adriana Gâz Florea, Hajnal Kelemen and Daniela-Lucia Muntean

Abstract

As more data are generated from proteome and transcriptome analysis revealing that metalloproteinases represent most of the Viperid and Colubrid venom components authors decided to describe in a short review a classification and some of the multiple activities of snake venom metalloproteinases. SVMPs are classified in three major classes (P-I, P-II and P-III classes) based on the presence of various domain structures and according to their domain organization. Furthermore, P-II and P-III classes were separated in subclasses based on distinctive post-translational modifications. SVMPs are synthesized in a latent form, being activated through a Cys-switch mechanism similar to matrix metalloproteinases. Most of the metalloproteinases of the snake venom are responsible for the hemorrhagic events but also have fibrinogenolytic activity, poses apoptotic activity, activate blood coagulation factor II and X, inhibit platelet aggregation, demonstrating that SVMPs have multiple functions in addition to well-known hemorrhagic function.

Open access

Kelemen Hajnal, Hancu Gabriel, Rusu Aura, Varga Erzsébet and Székely Szentmiklósi Blanka

Abstract

Prodrugs are chemically modified derivatives introduced in therapy due to their advantageous physico-chemical properties (greater stability, improved solubility, increased permeability), used in inactive form. Biological effect is exerted by the active derivatives formed in organism through chemical transformation (biotransformation). Currently, 10% of pharmaceutical products are used as prodrugs, nearly half of them being converted to active form by hydrolysis, mainly by ester hydrolysis. The use of prodrugs aims to improve the bioavailability of compounds in order to resolve some unfavorable characteristics and to reduce first-pass metabolism. Other objectives are to increase drug absorption, to extend duration of action or to achieve a better tissue/organ selective transport in case of non-oral drug delivery forms. Prodrugs can be characterized by chemical structure, activation mechanism or through the presence of certain functional groups suitable for their preparation. Currently we distinguish in therapy traditional prodrugs prepared by chemical derivatisation, bioprecursors and targeted delivery systems. The present article is a review regarding the introduction and applications of prodrug design in various areas of drug development.

Open access

Alexandru Robert Vlad, Gabriel Hancu, Hajnal Kelemen, Diana Ciurcă and Amelia Tero-Vescan

Abstract

Sibutramine is a chiral anti-obesity drug which decreases food intake and increases energy expenditure. In therapy it is used as a racemic mixture; however both pharmacokinetic and pharmacodynamic data have revealed enantioselective behavior of sibutramine and its major active metabolites. Several chromatographic and electrophoretic analytical methods have been published so far for the chiral determination of sibutramine from pharmaceutical preparations and biological samples. The current paper aims to provide a systematic review of the stereochemical aspects and analytical methods used for the enantiodetermination of sibutramine and its active enantiomers covering the last 15 years.

Open access

Erzsebet Varga, Ibolya Schmidt, Beáta Szövérfi, Mădălina Daniela Pop, Hajnal Kelemen and Anita Tóth

Abstract

Objective: The aim of the study was to determine the content of polyphenols and flavonoids from sixteen selected medicinal plants from the spontaneous Romanian flora and fifteen tinctures obtained with propylene glycol.

Methods: The polyphenols were determined by the Folin-Ciocalteu method while the flavonoids by using a colorimetric method from the 10th edition of the Romanian Pharmacopoeia. The antioxidant activities of the most common nine medicinal plants and fifteen tinctures were determined by DPPH and ABTS methods.

Results: The results highlighted that the phenolic compounds and flavonoids have contributed to their antioxidant activities and the medicinal plants and tinctures included in the study are rich sources of natural antioxidants.

Conclusions: There are a wide variety of extraction methods for the determination of phenolics and flavonoids. The study confirms a correlation between phenolic and flavonoid contents obtained by using the DPPH and ABTS tests.

Open access

Hajnal Kelemen, Gabriel Hancu, Serban Andrei Gâz-Florea, Eniko Nemes-Nagy, Lajos Attila Papp and Eleonora Mircia

Abstract

Objective: Miconazole, an imidazole antifungal derivative, is a very hydrophobic compound, a major drawback in obtaining topical pharmaceutical formulations with optimal bioavailability. Cyclodextrins (CDs) may increase local drug delivery by enhancing the drug release and/or permeation. The aim of the study is the characterization of inclusion complexes between miconazole and different CD derivatives.

Methods: Several CD derivatives were tested in the experiments. The binary systems between miconazole and different CDs were prepared in 1:1 molar ratios by physical-mixture and kneading methods. Differential scanning calorimetry (DSC) and Fourier transformed-infrared spectroscopy (FT-IR) methods were used to characterize solid state interactions between miconazole and CDs in their binary systems.

Results: The FT-IR analysis suggests the formation of a new solid phase, indicating a molecular interaction between the components. The DSC analysis sustains the hypothesis of formation of partial inclusion complexes between miconazole nitrate and CD.

Conclusion: The thermic behaviour of the complexes depends both on the preparation method and the composition of the products.

Open access

Adriana Modroiu, Gabriel Hancu, Robert Alexandru Vlad, Ștefana Stăcescu, Ruxandra Soare and Hajnal Kelemen

Abstract

A rapid, simple and sensitive capillary zone electrophoresis method was developed for the simultaneous determination of amlodipine besylate and telmisartan, in fixed-dose combinations, through the utilization of a UV photodiode array detector. Electrophoretic parameters such as buffer concentration and pH, system temperature, applied voltage and injection parameters, were optimized in order to improve the efficiency of the separation. The best results were obtained when employing fused silica capillary (48 cm length X 50 μm ID) and 50 mM phosphate buffer electrolyte at pH 4.50, + 25 kV applied voltage, as well as 25°C system temperature. The separation was achieved in approximately 3 minutes, with a resolution of 4.90, while the order of migration was amlodipine followed by telmisartan. The analytical performance of the method was verified with regard to linearity, precision and robustness. In addition, the limit of detection and the quantification were calculated.

Open access

Aura Rusu, Gabriel-Cosmin Popescu, Silvia Imre, Valentin Ion, Szende Vancea, Anda-Lavinia Grama, Hajnal Kelemen and Gabriel Hancu

Abstract

Objective: Silver complexes of antibacterial quinolones have the potential advantage of combining the antibacterial activity of silver and fluoroquinolones. The objective of our study was the preparation and the preliminary physico-chemical characterization of a silver complex with ofloxacin.

Methods: To achieve our goals several spectroscopic methods (ultraviolet spectrophotometry, mass spectrometry, and Fourier transform infrared spectroscopy) and thermal methods (differential scanning calorimetry and thermogravimetric analysis) were used in order to elucidate the chemical structure of the complex.

Results: Using mass spectrometry we established the stoichiometric ratio silver:ofloxacin as 1:2. Experimental data suggest a particular coordination for ofloxacin, as a monodentate ligand, in the formation of a complex with silver, through the nitrogen atom from the methyl-piperazine cycle.

Conclusions: The obtained complex has a chemical structure likely [Ag(Ofloxacin)2]NO3, requiring evaluation through other physico-chemical methods.

Open access

Mircea Dumitru Croitoru, Ibolya Fülöp, Maria-Raluca Irimia-Constantin, Erzsébet Varga, Hajnal Kelemen, Erzsébet Fogarasi and Luana-Maria Faliboga

Abstract

Objective: the number of alkaloids like morphine and codeine found in poppy seeds used in food industry are monitored by a directive given by European Food Safety Authority. Based on this regulation the aim of the study was to determine the quantity of morphine and codeine from several brands of poppy seeds. Methods: an HPLC-UV method (205 nm) was developed to measure the quantity of morphine and codeine. Sample preparation was made using recipes posted on Drugs Forum by some users. Limits of detection were not determined because the lowest concentration from the reference (0.1 μg/ml) detected morphine concentrations that are far lower than a limit of toxicological concern. Results: The concentrations, which were found, ranged between Below the Level of Toxicological Concern (BLTC) - 243.26 mg/kg for morphine and BLTC - 88.58 mg/kg for codeine using several methods of preparation. Conclusions: one can observe that there are some brands of poppy seeds which do not respect the regulation about the amount of morphine and codeine. The high amount of morphine in some samples suggests that there are different varieties of poppy seeds, which can be used for an illicit purpose and can lead to addiction or even overdose in some cases.