We have prepared and studied silver nanoparticles functionalized with ligands based on lactic acid derivatives. Several types of hybrid systems that differed in the size of silver nanoparticles as well as the length of surface ligands were analyzed. Transmission electron microscopy (TEM) observation provided information about the size and shape of nanoparticles and proved good homogeneity of studied systems. By dynamic light scattering (DLS) measurements, we have measured the size distribution of nanoparticle systems. Plasmonic resonance was detected at around 450 nm. For two hybrid systems, the mesomorphic behaviour has been demonstrated by x-ray measurements. The observed thermotropic liquid crystalline phases reveal lamellar character. We have proposed a model based on self-assembly of intercalated liquid crystalline ligands.
- Klíčová slova
- liquid crystals, plasmonic, self-assembly, silver nanoparticles,
- Publikační typ
- časopisecké články MeSH
Two new impurities were described and determined using gradient HPLC method with UV detection in retigabine (RET). Using LC-HRMS, NMR and IR analysis the impurities were identified as RET-dimer I: diethyl {4,4'-diamino-6,6'-bis[(4-fluorobenzyl)amino]biphenyl-3,3'-diyl}biscarbamate and RET-dimer II: ethyl {2-amino-5-[{2-amino-4-[(4-fluorobenzyl) amino] phenyl} (ethoxycarbonyl) amino]-4-[(4-fluorobenzyl)amino] phenyl}carbamate. Reference standards of these impurities were synthesized followed by semipreparative HPLC purification. The mechanism of the formation of these impurities is also discussed. An HPLC method was optimized in order to separate, selectively detect and quantify all process-related impurities and degradation products of RET. The presented method, which was validated in terms of linearity, limit of detection (LOD), limit of quantification (LOQ) and selectivity is very quick (less than 11min including re-equilibration time) and therefore highly suitable for routine analysis of RET related substances as well as stability studies.
- Klíčová slova
- HPLC, Identification, Process-related impurities, Retigabine, Synthesis,
- MeSH
- fenylendiaminy chemie MeSH
- karbamáty chemie MeSH
- kontaminace léku MeSH
- limita detekce MeSH
- referenční standardy MeSH
- stabilita léku MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- ezogabine MeSH Prohlížeč
- fenylendiaminy MeSH
- karbamáty MeSH
The acid hydrolysis of various selected saccharide- and polysaccharide-based pharmaceutical excipients under acid hydrolysis and the formation of degradation compounds were studied. New degradation products formed from these excipients were discovered. Liquid chromatography-mass spectrometry and nuclear magnetic resonance techniques were employed to identify and fully characterize these unknown compounds. The degradation products were identified as [(5-formylfuran-2-yl)methoxy]acetic acid, 5-[(propan-2-yloxy)methyl]furan-2-carbaldehyde, along with the previously identified 5-(methoxymethyl)furan-2-carbaldehyde. On the basis of the identification of these degradation products, a reasonable mechanism for their formation can be proposed. Temperature and pH affect the hydrolysis rates of saccharides and polysaccharides, which in turn affects the rate of formation of furfural compounds.
- MeSH
- 2-furaldehyd chemická syntéza MeSH
- hmotnostní spektrometrie MeSH
- hydrolýza MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- léčivé přípravky chemie MeSH
- limita detekce MeSH
- magnetická rezonanční spektroskopie MeSH
- polysacharidy chemie MeSH
- pomocné látky * MeSH
- reprodukovatelnost výsledků MeSH
- sacharidy chemie MeSH
- teplota MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Publikační typ
- časopisecké články MeSH
- validační studie MeSH
- Názvy látek
- 2-furaldehyd MeSH
- léčivé přípravky MeSH
- polysacharidy MeSH
- pomocné látky * MeSH
- sacharidy MeSH
Different pharmaceutical preparations against the common cold containing phenylephrine (PHE) and saccharose were studied. New impurities were discovered in these preparations after exposure using isocratic ion-pair chromatography separation on a C18 column. LC-MS and NMR techniques were employed to identify and to fully characterize these new compounds. The products were identified as 1-[5-(hydroxymethyl)-2-furyl]-2-methyl-1,2,3,4-tetrahydroisochinolin-4,8-diol and 1-[5-(hydroxymethyl)-2-furyl]-2-methyl-1,2,3,4-tetrahydroisochinolin-4,6-diol. Identification of these degradation products allowed to understand and to confirm their formation mechanism. The developed HPLC method separates of all known impurities and impurities originated from PHE as well.
- MeSH
- chemické modely MeSH
- chemické techniky analytické MeSH
- chemie farmaceutická metody MeSH
- chromatografie kapalinová metody MeSH
- fenylefrin analýza chemie MeSH
- hmotnostní spektrometrie metody MeSH
- kontaminace léku MeSH
- léčivé přípravky analýza MeSH
- magnetická rezonanční spektroskopie metody MeSH
- pomocné látky chemie MeSH
- sacharosa analýza MeSH
- stabilita léku MeSH
- vysokoúčinná kapalinová chromatografie metody MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fenylefrin MeSH
- léčivé přípravky MeSH
- pomocné látky MeSH
- sacharosa MeSH
The gastrointestinal absorption of bisphosphonates is in general only about 1%. To address this problem mixtures of risedronate monosodium salt with twelve varied sugar alcohols, furanoses, pyranoses and eight gluco-, manno- and galactopyranoside derivatives as counterions were designed in an effort to prepare co-crystals/new entities with improved intestinal absorption. Crystalline forms were generated by means of kinetically and/or thermodynamically controlled crystallization processes. One hundred and fifty-two prepared samples were screened by means of FT-NIR and FT-Raman spectroscopy. No co-crystal was prepared, but noteworthy results were obtained. A new solid phase of risedronate monosodium salt generated in the presence of phenyl-β-d-galactopyranoside under thermodynamically controlled crystallization conditions was found and also characterized using solid state NMR spectroscopy, X-ray powder diffraction and differential scanning calorimetry. This new polymorph was named as form P. Interactions between risedronate monosodium salt and both carbohydrates were confirmed by means of molecular dynamics simulation. In the present study the relationships between the chemical structures of the studied compounds required for crystalline form change are discussed.
- MeSH
- diferenciální skenovací kalorimetrie MeSH
- difrakce rentgenového záření MeSH
- galaktosidy chemie MeSH
- krystalizace MeSH
- kyselina etidronová analogy a deriváty chemie MeSH
- kyselina risedronová MeSH
- magnetická rezonanční spektroskopie MeSH
- molekulární struktura MeSH
- Ramanova spektroskopie MeSH
- sacharidy chemie MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- galaktosidy MeSH
- kyselina etidronová MeSH
- kyselina risedronová MeSH
- phenyl-D-galactopyranoside MeSH Prohlížeč
- sacharidy 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.
- MeSH
- bisfosfonáty chemie MeSH
- galaktosidy chemie MeSH
- glukosa analogy a deriváty chemie MeSH
- krystalizace MeSH
- kyselina ibandronová MeSH
- Ramanova spektroskopie metody MeSH
- spektroskopie infračervená s Fourierovou transformací metody MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- bisfosfonáty MeSH
- galaktosidy MeSH
- glukosa MeSH
- kyselina ibandronová MeSH
- phenyl-D-galactopyranoside MeSH Prohlížeč
Solid complexes of D-galacturonic acid (GalA) with cobalt(II), copper(II), nickel(II) and oxovanadium(IV) (1-4) were prepared and characterised. The metal-to-ligand molar ratio was 1:2 for complexes 1-3 and 1:1 for complex 4. The alpha- and beta-anomers of GalA were detected in all the complexes in solid state and in solutions. An addition of small amounts of the paramagnetic complexes to the D2O solution of pure ligand led to NMR line broadening of some 1H and 13C nuclei. This broadening was sensitive to the anomeric state of GalA in the case of complexes 1 and 4. NMR and vibrational spectroscopic data indicate the formation of carboxylate complexes of all the cations, while noncarboxylic oxygens are also involved into the metal bonding in some cases. VCD spectra of complexes 1-4 in D2O and Me2SO-d6 solutions confirm that GalA carboxylic group may participate in the formation of optically active species around the metal cation. Possible ways of GalA coordination by metal cations of this study were proposed and discussed.
- MeSH
- kationty dvojmocné chemie MeSH
- kyseliny hexuronové chemie MeSH
- magnetická rezonanční spektroskopie MeSH
- molekulární struktura MeSH
- roztoky MeSH
- těžké kovy chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- galacturonic acid MeSH Prohlížeč
- kationty dvojmocné MeSH
- kyseliny hexuronové MeSH
- roztoky MeSH
- těžké kovy MeSH
PURPOSE: To evaluate the function of the blood aqueous barrier(BAB) in the eyes with silicone oil emulsification (SOE). METHODS: Protein concentrations, expressed in albumin equivalents,were determined in aqueous humor of the eyes with SOE in 11 consecutive patients by means of proton nuclear magnetic resonance (1H NMR) spectroscopy. Correlations with various clinical factors were studied. RESULTS: Normal function of the BAB (albumin equivalents 1mg/ml and less was found in 8 eyes (73%) independently on underlying disease, early postoperative reaction after pars plana vitrectomy with SO implantation, degree of SOE and late postoperative complications. Increased permeability of the BAB (albumin equivalents equal 2, 3 and 6.5 mg/ml) was found in 3 eyes (27%) with recent acute complication (retinal detachment after SO removal in 2 eyes, and secondary angle closure glaucoma in 1 eye). CONCLUSION: SOE in vivo was associated with increased permeability of the BAB in the minority of the eyes. Other factors should be studied to explain the variability of SOE. 1H NMR spectroscopy might be a valuable method for the study of SOE.
- MeSH
- albuminy metabolismus MeSH
- dospělí MeSH
- emulze farmakologie MeSH
- hematookulární bariéra účinky léků MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční spektroskopie MeSH
- nefelometrie a turbidimetrie MeSH
- protony MeSH
- senioři MeSH
- silikonové oleje farmakologie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- albuminy MeSH
- emulze MeSH
- protony MeSH
- silikonové oleje MeSH
