Aim: To study the four diastereomers of leucogen and structure of the related substances.
Methods: LC-DAD, LC-MS/MS and LC- 1H NMR were used. LC was carried out with a Phenomnex Luna C18 (250 mm x 4.60 mm ID, 5 microm) column and a mobile phase of water-acetonitrile-glacial acetic acid (58:42: 0.3).
Results: The structures of leucogen and its related substances were identified. Leucogen and the related substances were found to have four diastereomers in solution state separately. The stability and transformation of the four diastereomers were analyzed and 3R4S5R was found to be more stable than the others according to quantum calculations.
Conclusion: Leucogen have four diastereomers in solution state and it can transform from one diastereomer to the others, and the 3R4S5R is more stable than the others.
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Pharmaceutics
May 2023
Department of Analytical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk, Poland.
Reliable interpretation of the changes occurring in the samples during their heating is ensured by using more than one measurement technique. This is related to the necessity of eliminating the uncertainty resulting from the interpretation of data obtained by two or more single techniques based on the study of several samples analyzed at different times. Accordingly, the purpose of this paper is to briefly characterize thermal analysis techniques coupled to non-thermal techniques, most often spectroscopic or chromatographic.
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Department of Analytical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk, Poland.
Pharmaceutical excipients should not interact with active substances, however, in practice, they sometimes do it, affecting the efficacy, stability and safety of drugs. Thus, interactions between active substances and excipients are not desirable. For this reason, two component mixtures of oral antidiabetic drug linagliptin (LINA) with four excipients of different reactivity, i.
View Article and Find Full Text PDFPharmaceutics
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Department of Analytical Chemistry, Faculty of Pharmacy, Medical University of Gdansk, Gen. J. Hallera 107, 80-416 Gdansk, Poland.
As amorphization may improve the solubility and bioavailability of a drug substance, the aim of this work was to assess to what extent the crystallinity of caffeine (CAF) and theophylline (TF) can be reduced by homogenization with a polymeric excipient. To realize this purpose, the physical mixtures of both methylxanthines with hydroxypropyl methylcellulose (HPMC) were examined using differential scanning calorimetry (DSC), hot-stage microscopy (HSM), Fourier-transform infrared (FTIR) and Raman spectroscopy. Moreover, phase diagrams for the physical mixtures were calculated using theoretical data.
View Article and Find Full Text PDFYao Xue Xue Bao
July 2006
Department of Pharmaceutical Analysis, China Pharmaceutical University, Nanjing 210009, China.
Aim: To study the four diastereomers of leucogen and structure of the related substances.
Methods: LC-DAD, LC-MS/MS and LC- 1H NMR were used. LC was carried out with a Phenomnex Luna C18 (250 mm x 4.
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