The use of solid oral dosage forms depends on the degree of bioavailability of the active pharmaceutical ingredient. The rate and extent of the drug released from the dosage form and subsequently dissolved in the gastrointestinal fluids greatly affects its fate in the human body. In vitro dissolution test may provide an in-depth understanding of a drug formulation's behaviour in vivo, as long as it sufficiently simulates relevant gastrointestinal conditions. Therefore, the development of in vitro gastrointestinal systems, which reflects advanced technology and knowledge about the human body, is receiving considerable attention. This article is focused on the biorelevant dynamic apparatuses and their sophisticated design, overcoming many limitations of conventional dissolution devices and allowing a better correlation with in vivo behaviour of solid oral dosage forms.
- Publikační typ
- abstrakt z konference MeSH
- Publikační typ
- abstrakt z konference MeSH
Mixtures of ibandronate monosodium salt with eleven gluco- and/or galacto-pyranoside derivatives as counterions were designed to prepare co-crystals with improved intestinal absorption. In general, gastrointestinal absorption of bisphosphonates after oral administration is approximately 1%. Co-crystals were generated by means of thermodynamically and/or kinetically controlled crystallization processes. Seventy-seven prepared samples were analyzed by means of FT-NIR, FT-Raman spectrometry and solid state NMR spectroscopy. New entities of ibandronate monosodium salt with phenyl-β-D-galactopyranoside were found and characterized. The absorption of these potential new co-crystals was investigated by means of PAMPA experiments. In the present study the relationships between the chemical structures of the studied compounds required for co-crystal generation are discussed.
A series of sixteen pyrazinamide analogues with the -CONH- linker connecting the pyrazine and benzene rings was synthesized by the condensation of chlorides of substituted pyrazinecarboxylic acids with ring-substituted (chlorine) anilines. The prepared compounds were characterized and evaluated for their antimycobacterial and antifungal activity, and for their ability to inhibit photosynthetic electron transport (PET). 6-Chloro-N-(4-chlorophenyl)pyrazine-2-carboxamide manifested the highest activity against Mycobacterium tuberculosis strain H37Rv (65% inhibition at 6.25 μg/mL). The highest antifungal effect against Trichophyton mentagrophytes, the most susceptible fungal strain tested, was found for 6-chloro-5-tert-butyl-N-(3,4-dichlorophenyl)pyrazine-2-carboxamide (MIC=62.5 μmol/L). 6-chloro-5-tert-butyl-N-(4-chlorophenyl)pyrazine-2-carboxamide showed the highest PET inhibition in spinach chloroplasts (Spinacia oleracea L.) chloroplasts (IC50=43.0 μmol/L). For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds as well as their structure-activity relationships are discussed.
- MeSH
- antibakteriální látky chemická syntéza chemie farmakologie MeSH
- antifungální látky chemická syntéza chemie farmakologie MeSH
- chloroplasty metabolismus MeSH
- chlorované uhlovodíky chemická syntéza chemie farmakologie MeSH
- fotosyntéza účinky léků MeSH
- molekulární struktura MeSH
- Mycobacterium tuberculosis růst a vývoj MeSH
- pyrazinamid analogy a deriváty chemická syntéza chemie farmakologie MeSH
- Spinacia oleracea metabolismus MeSH
- Trichophyton růst a vývoj MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In the study, a series of twelve ring-substituted 4-hydroxy-1H-quinolin-2-one derivatives were prepared. The procedures for synthesis of the compounds are presented. The compounds were analyzed using RP-HPLC to determine lipophilicity and tested for their photosynthesis-inhibiting activity using spinach (Spinacia oleracea L.) chloroplasts. All the synthesized compounds were also evaluated for antifungal activity using in vitro screening with eight fungal strains. For all the compounds, the relationships between the lipophilicity and the chemical structure of the studied compounds are discussed, as well as their structure-activity relationships (SAR).
- MeSH
- antifungální látky chemie MeSH
- chinolony farmakologie chemická syntéza MeSH
- chloroplasty účinky léků MeSH
- financování organizované MeSH
- fotosyntéza účinky léků MeSH
- houby účinky léků MeSH
- hydrofobní a hydrofilní interakce MeSH
- hydroxychinoliny farmakologie chemická syntéza MeSH
- vztahy mezi strukturou a aktivitou MeSH
In this study, series of ring-substituted 2-styrylquinazolin-4(3H)-one and 4-chloro-2-styrylquinazoline derivatives were prepared. The syntheses of the discussed compounds are presented. The compounds were analyzed by RP-HPLC to determine lipophilicity. They were tested for their inhibitory activity on photosynthetic electron transport (PET) in spinach (Spinacia oleracea L.) chloroplasts. Primary in vitro screening of the synthesized compounds was also performed against four mycobacterial strains and against eight fungal strains. Several compounds showed biological activity comparable with or higher than that of the standard isoniazid. It was found that the electronic properties of the R substituent, and not the total lipophilicity of the compound, were decisive for the photosynthesis-inhibiting activity of tested compounds.
- MeSH
- antituberkulotika farmakologie chemická syntéza chemie MeSH
- atypické mykobakteriální infekce farmakoterapie MeSH
- bakteriální pneumonie farmakoterapie mikrobiologie MeSH
- chinazoliny farmakologie chemická syntéza chemie MeSH
- chloroplasty účinky léků MeSH
- fotosyntéza účinky léků MeSH
- lidé MeSH
- netuberkulózní mykobakterie účinky léků MeSH
- Spinacia oleracea účinky léků MeSH
- styreny farmakologie chemická syntéza MeSH
- transport elektronů účinky léků MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- práce podpořená grantem MeSH
Pyrazine derivatives show a wide range of biological activities. 1-Pyrazin-2-ylethan-1-ones have served as food flavourants, and together with pyrazine-2-carbonitriles have been widely used as intermediates in the synthesis of various heterocyclic compounds. In our laboratory, substituted pyrazine-2-carbonitriles and 1-pyrazin-2-ylethan-1-ones have been used as intermediates for the preparation of potential antifungal and antimycobacterial drugs. Using established methods, a library of pyrazine derivatives was synthesized. Homolytic alkylation of commercially available pyrazine-2-carbonitrile yielded a series of 5-alkylpyrazine-2-carbonitriles which were converted into the corresponding 1-(5-alkylpyrazin-2-yl)ethan-1-ones (5-alkyl-2-acetylpyrazines) via the Grignard reaction. Homolytic acetylation of pyrazine-2-carbonitrile yielded 5-acetylpyrazine-2-carbonitrile. Using the same procedure, 3-acetyl-5-tert-butylpyrazine-2-carbonitrile was obtained with 5-tert-butylpyrazine-2-carbonitrile as a starting material. The hydrophobicity of the compounds was determined both experimentally (RP-HPLC) and by computation (CS ChemOffice Ultra version 9.0, ACD/LogP version 1.0 and ACD/LogP version 9.04), and both the approaches were compared. New hydrophobicity constants ? based on experimental results were derived. These constants are markedly different from tabulated constants ? valid for benzene rings, and can be widely used in estimating physicochemical properties of new biologically active pyrazines.
New acetylcholinesterase reactivators with either a (E) or (Z)-but-2-ene connecting linker were recently prepared. The purity of the compounds was checked by HPLC and was found to be sufficient for in-vitro screening. All the discussed bispyridinium reactivators were analyzed by reversed-phase high performance liquid chromatography (RP-HPLC) to measure lipophilicity. The procedure was performed under isocratic conditions with methanol as organic modifier in the mobile phase using an end-capped non-polar C(18) stationary phase RP column. Relationships between the lipophilicity (logarithm of the RP-HPLC capacity factor, log k) and chemical structures of the studied compounds are discussed. Lipophilicity was different for the (E) and (Z) compounds and varied among the compounds in each of these groups. The lipophilicity differences also indicated an apparent influence of intramolecular interactions. Lipophilicity calculations (log P/Clog P) by means of commonly used software were not successful due to the presence of quaternary nitrogen atoms in the molecules of the reactivators.
- MeSH
- financování organizované MeSH
- kontaminace léku MeSH
- lipidy chemie MeSH
- molekulární struktura MeSH
- pyridinové sloučeniny chemie MeSH
- reagencia zkříženě vázaná chemie MeSH
- reaktivátory cholinesterázy analýza MeSH
- stereoizomerie MeSH
- vinylové sloučeniny MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
Improvements in stationary phase stability have been and remain a great task for research of new stationary phases. Metal oxide-based stationary phases appear as one of perspective alternatives to classical silica based stationary phases regarding to their similar effectiveness, different selectivity, different retention mechanism and mainly better chemical and thermal stability. In this study, the retention behaviour of ondansetron and its five pharmacopoeial impurities on TiO(2)-based reversed phase was investigated. The influence of buffer type, pH and concentration on retention was studied. Different types and amount of organic solvent in mobile phase were tested. The effect of temperature and flow rate on separation was investigated. The separation conditions were optimized and developed method validated. The retention parameters - retention time (t(R)), retention factor (k'), theoretical plate number (N), resolution between peaks due to nearby peaks (R(s)) and symmetry factor (A(s)) have been compared to parameters achieved on polybutadiene-coated zirconia column. The thermodynamic parameters of retention of analysed compounds - enthalpy, entropy and Gibbs free energy - were calculated and compared to those achieved on polybutadiene-coated zirconia column. This work proves similarity of retention behaviour of ondansetron and its five related compounds on zirconia-based and titania-based stationary phases and potential utilisation of polyethylene covered TiO(2)-based reversed stationary phase as an alternative to polybutadiene-coated ZrO(2) stationary phase in pharmaceutical analysis of ondansetron.
