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Nowosielski B, Jamrógiewicz M, Łuczak J, Tercjak A, Warmińska D. Effect of temperature and composition on physical properties of deep eutectic solvents based on 2-(methylamino)ethanol – measurement and prediction. J Mol Liq 2023. [DOI: 10.1016/j.molliq.2022.121069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Mikolaszek B, Jamrógiewicz M, Mojsiewicz-Pieńkowska K, Sznitowska M. Microscopic and Spectroscopic Imaging and Thermal Analysis of Acrylates, Silicones and Active Pharmaceutical Ingredients in Adhesive Transdermal Patches. Polymers (Basel) 2022; 14:polym14142888. [PMID: 35890664 PMCID: PMC9322838 DOI: 10.3390/polym14142888] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 02/04/2023] Open
Abstract
Dermal or transdermal patches are increasingly becoming a noteworthy alternative as carriers for active pharmaceutical ingredients (APIs), which makes their detailed physicochemical evaluation essential for pharmaceutical development. This paper demonstrates mid-infrared (FTIR) and Raman spectroscopy with complementary microscopic methods (SEM, optical and confocal Raman microscopy) and differential scanning calorimetry (DSC) as tools for the identification of the state of model API (testosterone TST, cytisine CYT or indomethacin IND) in selected adhesive matrices. Among the employed spectroscopic techniques, FTIR and Raman may be used not only as standard methods for API identification in the matrix, but also as a means of distinguishing commercially available polymeric materials of a similar chemical structures. A novel approach for the preparation of adhesive polymers for the FTIR analysis was introduced. In silicone matrices, all three APIs were suspended, whereas in the case of the acrylic PSA, Raman microscopy confirmed that only IND was dissolved in all three acrylic matrices, and the dissolved fraction of the CYT differed depending on the matrix type. Moreover, the recrystallization of TST was observed in one of the acrylates. Interestingly, a DSC analysis of the acrylic patches did not confirm the presence of the API even if the microscopic images showed suspended particles.
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Affiliation(s)
- Barbara Mikolaszek
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Gdańsk, 80-416 Gdańsk, Poland;
| | - Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, 80-416 Gdańsk, Poland; (M.J.); (K.M.-P.)
| | - Krystyna Mojsiewicz-Pieńkowska
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, 80-416 Gdańsk, Poland; (M.J.); (K.M.-P.)
| | - Małgorzata Sznitowska
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Gdańsk, 80-416 Gdańsk, Poland;
- Correspondence: ; Tel.: +48-58-349-1080; Fax: +48-58-349-1090
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Nowosielski B, Jamrógiewicz M, Łuczak J, Warmińska D. Novel Binary Mixtures of Alkanolamine Based Deep Eutectic Solvents with Water—Thermodynamic Calculation and Correlation of Crucial Physicochemical Properties. Molecules 2022; 27:molecules27030788. [PMID: 35164052 PMCID: PMC8840229 DOI: 10.3390/molecules27030788] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/20/2022] [Accepted: 01/23/2022] [Indexed: 12/04/2022] Open
Abstract
This paper demonstrates the assessment of physicochemical and thermodynamic properties of aqueous solutions of novel deep eutectic solvent (DES) built of tetrabutylammonium chloride and 3-amino-1-propanol or tetrabutylammonium bromide and 3-amino-1-propanol or 2-(methylamino)ethanol or 2-(butylamino)ethanol. Densities, speeds of sound, refractive indices, and viscosities for both pure and aqueous mixtures of DES were investigated over the entire range of compositions at atmospheric pressure and T = (293.15 ‒ 313.15) K. It was concluded that the experimental data were successfully fitted using the Jouyban–Acree model with respect to the concentration. Obtained results showed that this mathematical equation is an accurate correlation for the prediction of aqueous DES properties. Key physicochemical properties of the mixtures—such as excess molar volumes, excess isentropic compressibilities, deviations in viscosity, and deviations in refractive indices—were calculated and correlated by the Redlich–Kister equation with temperature-dependent parameters. The non-ideal behavior of the studied systems were also evaluated by using the Prigogine−Flory−Patterson theory and the results were interpreted in terms of interactions between the mixture components.
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Affiliation(s)
- Bartosz Nowosielski
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland;
| | - Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland;
| | - Justyna Łuczak
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland;
| | - Dorota Warmińska
- Department of Physical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, ul. Narutowicza 11/12, 80-233 Gdańsk, Poland;
- Correspondence: ; Tel.: +48-583471410
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Jamrógiewicz M, Józefowicz M. Preparation and Characterization of Indomethacin Supramolecular Systems with β-Cyclodextrin in Order to Estimate Photostability Improvement. Molecules 2021; 26:molecules26247436. [PMID: 34946517 PMCID: PMC8709320 DOI: 10.3390/molecules26247436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 11/30/2021] [Accepted: 12/03/2021] [Indexed: 11/16/2022] Open
Abstract
Cyclodextrins have found wide application in contemporary chemistry, pharmacy and medicine. Because of their unique properties, cyclodextrins are constantly used in research on solubility or stability improvement, as well as other physicochemical properties of medicinal substances. Indomethacin (IND) is a photolabile molecule that also attracts the interest of researchers due to its therapeutic potential and the need to overcome its problematic photosensitivity. Supramolecular complexes of indomethacin with β-cyclodextrin (CD) are already known, and they show greater stability compared to complexes with other types of cyclodextrins. So far, however, the sensitivity to light of physical mixtures and inclusion complexes in the solid phase has not been studied, and their various stoichiometries have not yet been investigated. Due to this fact, the aim of the present study is to obtain supramolecular systems (inclusion complexes and physical mixtures) of indomethacin with three different amounts of β-cyclodextrin. Assessment of the photochemical stability of indomethacin-β-cyclodextrin systems in the solid state is performed in order to find the best correlation between IND stability and the amount of CD. Comparative analysis of physicochemical degradation for stoichiometry systems [CD:IND] = [1:1], [0.5:1] and [0.1:1] is performed by using ultraviolet spectroscopy, transmission—FTIR, reflection—ATR-FTIR infrared spectroscopy and DSC calorimetry.
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Affiliation(s)
- Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdańsk, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland
- Correspondence: ; Tel.: +48-58-349-16-56
| | - Marek Józefowicz
- Institute of Experimental Physics, Faculty of Mathematics, Physics and Informatics, University of Gdańsk, Wita Stwosza 57, 80-308 Gdańsk, Poland;
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Jamrógiewicz M, Milewska K, Mikolaszek B. Spectroscopic evaluation on pseudopolymorphs of sodium naproxen. Spectrochim Acta A Mol Biomol Spectrosc 2021; 261:120018. [PMID: 34091357 DOI: 10.1016/j.saa.2021.120018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 05/20/2021] [Accepted: 05/22/2021] [Indexed: 06/12/2023]
Abstract
This paper demonstrates the assessment of vibrational spectroscopy methods such as middle infrared, near infrared and Raman spectroscopy (FTIR, FT-NIR, Raman) for the identification of pseudopolymorphic forms of a model active pharmaceutical ingredient (API) - sodium naproxen (NpxNa). NpxNa, in the form of three different pseudopolymorphs, was investigated by methods dedicated for solid state characterization: DSC (differential scanning calorimetry), XPRD (powder X-ray diffraction), SEM (scanning electron microscopy) and Karl Fischer titration. Novelty in the results sourced in the usage of the method not applied so far to identify pseudopolymorphic forms of NpxNa, that is, FTIR and FT-NIR. Based on the obtained reproduceable results, various pseudopolymorphic forms were successfully evaluated. Spectroscopic data were correlated with DSC and XPRD results. It was concluded that the combination of band's variations visible on the spectra of pseudopolymorphic forms will allow to interpretate the results unequivocally in case of crucial stability tests of medicinal substance or during on-line pharmaceutical process development by FTIR, FT-NIR and Raman spectroscopy.
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Affiliation(s)
- Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland.
| | - Karolina Milewska
- Department of Physical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland
| | - Barbara Mikolaszek
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Medical University of Gdansk, Al. Gen. Hallera 107, 80-416 Gdańsk, Poland
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Jamrógiewicz M, Karczewska-Kaliszak A, Milewska K. Light-sensitive medicinal compounds – the actual review of studies and strategies in proceedings. Farm Pol 2019. [DOI: 10.32383/farmpol/115045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Jamrógiewicz M, Milewska K. Studies on the influence of β-cyclodextrin derivatives on the physical stability of famotidine. Spectrochim Acta A Mol Biomol Spectrosc 2019; 219:346-357. [PMID: 31055241 DOI: 10.1016/j.saa.2019.04.066] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/15/2019] [Accepted: 04/23/2019] [Indexed: 06/09/2023]
Abstract
The usage of Fourier transform infrared spectroscopy, near infrared spectroscopy, differential scanning calorimetry and microscopy is presented in this work focused on the exploration of the effect of CD on the physical stability of famotidine (FAM). The most significant information was achieved by analysis of the second derivatives of near infrared (NIR) spectra recorded. Changes in the shape of spectra derivatives allow to observe the improvement of physical stability of FAM with the usage of various supramolecular systems based on β-cyclodextrin (CD) derivatives. The comparison was performed with the usage of maltodextrin in FAM mixtures. We found out that β-cyclodextrin derivatives in the form of physical mixture and inclusion complexes successfully increased the physical stability of famotidine in solid state while maltodextrin does not show positive effect in imparting physical stability to famotidine.
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Affiliation(s)
- Marzena Jamrógiewicz
- Department of Physical Chemistry, Medical University of Gdansk, 80-416 Gdańsk, Al. Gen. Hallera 107, Poland.
| | - Karolina Milewska
- Department of Physical Chemistry, Medical University of Gdansk, 80-416 Gdańsk, Al. Gen. Hallera 107, Poland
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Milewska K, Klucznik K, Jamrógiewicz M. Sacharides and their derivatives as pharmaceutical additives. Farm Pol 2018. [DOI: 10.32383/farmpol/118629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Jamrógiewicz M, Milewska K, Lewandowska K, Czubak K. Definitions and analytical procedures concerning pharmaceutical compound stability and the shelf-life of the drug product. Farm Pol 2018. [DOI: 10.32383/farmpol/119462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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Mojsiewicz-Pieńkowska K, Jamrógiewicz M, Szymkowska K, Krenczkowska D. Direct Human Contact with Siloxanes (Silicones) – Safety or Risk Part 1. Characteristics of Siloxanes (Silicones). Front Pharmacol 2016; 7:132. [PMID: 27303296 PMCID: PMC4884743 DOI: 10.3389/fphar.2016.00132] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 11/13/2022] Open
Abstract
Siloxanes are commonly known as silicones. They belong to the organosilicon compounds and are exclusively obtained by synthesis. Their chemical structure determines a range of physicochemical properties which were recognized as unique. Due to the susceptibility to chemical modifications, ability to create short, long or complex polymer particles, siloxanes found an application in many areas of human life. Siloxanes differ in particle size, molecular weight, shape and chemical groups. As a result, this determines the different physico-chemical properties, that directly affect the safety or the risk of their use. The areas that can be a source of danger to human health will be commented in this paper.
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Pikul P, Jamrógiewicz M, Nowakowska J, Hewelt-Belka W, Ciura K. Forced Degradation Studies of Ivabradine and In Silico Toxicology Predictions for Its New Designated Impurities. Front Pharmacol 2016; 7:117. [PMID: 27199759 PMCID: PMC4855699 DOI: 10.3389/fphar.2016.00117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 04/19/2016] [Indexed: 11/18/2022] Open
Abstract
All activities should aim to eliminate genotoxic impurities and/or protect the API against degradation. There is a necessity to monitor impurities from all classification groups, hence ivabradine forced degradation studies were performed. Ivabradine was proved to be quite durable active substance, but still new and with insufficient stability data. Increased temperature, acid, base, oxidation reagents and light were found to cause its degradation. Degradation products were determined with the usage of HPLC equipped with Q-TOF-MS detector. Calculations of pharmacological and toxicological properties were performed for six identified degradation products. Target prediction algorithm was applied on the basis of Hyperpolarization-activated cyclic nucleotide-gated cation channels, as well as more general parameters like logP and aqueous solubility. Ames test and five cytochromes activities were calculated for toxicity assessment for selected degradation products. Pharmacological activity of photodegradation product (UV4), which is known as active metabolite, was qualified and identified. Two other degradation compounds (Ox1 and N1), which were formed during degradation process, were found to be pharmacologically active.
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Affiliation(s)
- Piotr Pikul
- Department of Physical Chemistry, Faculty of Pharmacy with the Subfaculty of Laboratory Medicine, Medical University of GdańskGdańsk, Poland
| | - Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy with the Subfaculty of Laboratory Medicine, Medical University of GdańskGdańsk, Poland
| | - Joanna Nowakowska
- Department of Physical Chemistry, Faculty of Pharmacy with the Subfaculty of Laboratory Medicine, Medical University of GdańskGdańsk, Poland
| | - Weronika Hewelt-Belka
- Department of Analytical Chemistry, Chemical Faculty, Gdańsk University of TechnologyGdañsk, Poland
- Mass Spectrometry and Chromatography Laboratory, Pomeranian Science and Technology ParkGdynia, Poland
| | - Krzesimir Ciura
- Department of Physical Chemistry, Faculty of Pharmacy with the Subfaculty of Laboratory Medicine, Medical University of GdańskGdańsk, Poland
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Jamrógiewicz M. Consequences of New Approach to Chemical Stability Tests to Active Pharmaceutical Ingredients. Front Pharmacol 2016; 7:17. [PMID: 26955356 PMCID: PMC4744843 DOI: 10.3389/fphar.2016.00017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/18/2016] [Indexed: 11/24/2022] Open
Abstract
There is a great need of broaden look on stability tests of active pharmaceutical ingredients (APIs) in comparison with current requirements contained in pharmacopeia. By usage of many modern analytical methods the conception of monitoring the changes of APIs during initial stage of their exposure to harmful factors has been developed. New knowledge must be acquired in terms of identification of each degradation products, especially volatile ones. Further research as toxicology prediction during in silico studies of determined and identified degradation products is necessary. In silico methods are known as computational toxicology or computer-assisted technologies which are used for predicting toxicology of pharmaceutical substances such as impurities or degradation products. This is a specialized software and databases intended to calculate probability of genotoxicity or mutagenicity of these substances through a chemical structure-based screening process and algorithm specific to a given software program. Applying of new analytical approach is proposed as the usage of PAT tools, XRD, HS-SPME GC-MS/MS, LC-MS/MS for stability testing. Described improvements should be taken into account in case of each drug existing already in the market as well as being implemented as new one.
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Affiliation(s)
- Marzena Jamrógiewicz
- Department of Physical Chemistry, Faculty of Pharmacy with Subfaculty of Laboratory Medicine, Medical University of Gdansk Gdansk, Poland
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Mojsiewicz-Pieńkowska K, Jamrógiewicz M, Żebrowska M, Mikolaszek B, Sznitowska M. Double layer adhesive silicone dressing as a potential dermal drug delivery film in scar treatment. Int J Pharm 2015; 481:18-26. [DOI: 10.1016/j.ijpharm.2015.01.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 01/24/2015] [Accepted: 01/28/2015] [Indexed: 11/26/2022]
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15
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Jamrógiewicz M, Wielgomas B, Strankowski M. Evaluation of the photoprotective effect of β-cyclodextrin on the emission of volatile degradation products of ranitidine. J Pharm Biomed Anal 2014; 98:113-9. [DOI: 10.1016/j.jpba.2014.05.014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/04/2014] [Accepted: 05/09/2014] [Indexed: 11/15/2022]
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Jamrógiewicz M, Cal K, Gruszecka M, Ciesielski A. Determination of API content in a pilot-scale blending by near-infrared spectroscopy as a first step method to process line implementation. Acta Pol Pharm 2013; 70:419-429. [PMID: 23757932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Near infrared (NIR) spectroscopy was used for estimation of powder blend homogeneity and manufacturing control of a medicinal product powder mixture containing active pharmaceutical ingredient (API). Aiming at initiating a Process Analytical Technology (PAT) activity, the first step was a stationary mode at-line evaluation. In this, the content of pharmaceutical active compound in the powder mixtures intended to the direct tabletting was estimated based on recorded NIR spectra. Five formulations containing different quantities of API were prepared and analyzed also by a reference method--UV-Vis spectroscopy. A chemometric model was developed for calculation of the API amount in the mixtures. The Principal Component Regression (PCR) and Partial Least Squares (PLS) algorithms were used to obtain a model useful in further implementation for the PAT recommendations, into in-line blending control.
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Affiliation(s)
- Marzena Jamrógiewicz
- Medical University of Gdansk, Faculty of Pharmacy with Subfaculty of Laboratory Medicine, Department of Physical Chemistry, 80-416 Gdańsk, Hallera 107, Poland.
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Jamrógiewicz M, Wielgomas B. Detection of some volatile degradation products released during photoexposition of ranitidine in a solid state. J Pharm Biomed Anal 2013; 76:177-82. [DOI: 10.1016/j.jpba.2012.12.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 12/16/2012] [Accepted: 12/17/2012] [Indexed: 11/16/2022]
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Luboch E, Wagner-Wysiecka E, Jamrógiewicz M, Szczygelska-Tao J, Magiełka S, Biernat JF. Determination of the chemical structure of potential organic impurities occurring in the drug substance opipramol. Pharmazie 2010; 65:239-244. [PMID: 20432617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The tricyclic antipsychotic and antidepressant drug opipramol (opipramole) was examined with regard to the chemical structure of its organic impurities. Impurities were isolated from the technical product by chromatographic methods and their chemical structures were established by 1H NMR, MS and FTIR and further confirmed by comparison with commercially available products or with products obtained by independent synthesis, and in one case additionally by X-ray structure analysis.
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Affiliation(s)
- E Luboch
- Department of Chemical Technology, Chemical Faculty, Gdańsk University of Technology, Gdańsk, Poland.
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Affiliation(s)
- Kamila Sadowska
- a Department of Chemical Technology , Gdańsk University of Technology , Narutowicza, Gdańsk, Poland
| | - Marzena Jamrógiewicz
- a Department of Chemical Technology , Gdańsk University of Technology , Narutowicza, Gdańsk, Poland
| | - Jan F. Biernat
- a Department of Chemical Technology , Gdańsk University of Technology , Narutowicza, Gdańsk, Poland
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20
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Jabłonowska E, Pałys B, Wagner-Wysiecka E, Jamrógiewicz M, Biernat JF, Bilewicz R. pH-tunable equilibria in azocrown ethers with histidine moieties. Bioelectrochemistry 2007; 71:99-106. [PMID: 17081808 DOI: 10.1016/j.bioelechem.2006.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Revised: 09/07/2006] [Accepted: 09/17/2006] [Indexed: 11/22/2022]
Abstract
The crown ethers with electro- and photoactive azo moieties containing substituents with mobile protons such as in the -COOH groups of histidine, show unique effect of pH switched on/off presence of the azo form. The differences observed for the electrochemical behavior of azocrown ethers with N-acetylhistidine and imidazole moieties reveal the interference of a chemical reduction pathway in strongly acidified solutions. This chemical reduction process leads to the formation of a hydrazine derivative which can be detected by its further electroreduction on the electrode surface. The involvement of chemical reduction is seen clearly in the presence of mobile protons of the -COOH group and mercury as the electrode substrate. The behaviour of the N-acetylhistidine azomacrocyle is similar to that of compounds known to exist in quinone-hydrazone tautomeric equilibria.
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Affiliation(s)
- Elzbieta Jabłonowska
- Department of Chemistry, University of Warsaw, ul. Pasteura 1, 02093 Warsaw, Poland
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