Mesoporous material SBA-15 was functionalized with different polar and nonpolar groups: 3-aminopropyl, (SBA-15-NH2), 3-isocyanatopropyl (SBA-15-NCO), 3-mercaptopropyl (SBA-15-SH), methyl (SBA-15-CH3) and phenyl (SBA-15-Ph). The resulting surface grafted materials were investigated as matrices for controlled drug delivery. Anticancer agent, pemetrexed (disodium pemetrexed heptahydrate) was selected as a model drug and loaded in the unmodified and functionalized SBA-15 materials. Materials were characterized by elemental analysis, infrared spectroscopy, transmission electron microscopy, nitrogen adsorption/desorption analysis, small angle X-ray scattering, powder X-ray diffraction, solid state NMR spectroscopy and thermogravimetry. It was shown that surface modification has an impact on both encapsulated drug amount and release properties. Release experiments were performed into two media with different pH: simulated body fluid (pH = 7.4) and simulated gastric fluid (pH = 2). In general, the effect of pH was reflected by the lower release of pemetrexed under acidic conditions (pH = 2) compared to slightly alkaline saline environment (pH = 7.4). The release rate of pemetrexed from propylamine-, propylisocyanate- and phenyl-modified SBA-15 was found to be effectively controlled by intermolecular interactions as compared to that from pure SBA-15, SBA-15-SH, and SBA-15-CH3, that evidenced a steady and similar release. The highest release was observed for methyl-functionalized material whose hydrophobic surface accelerates the pemetrexed release. The data obtained from release studies were fitted using various kinetic models to determine the pemetrexed release mechanism and its release rate. The best correlations were found for Korsmeyer-Peppas and Higuchi models. Moreover, the theoretical three-parameter model for drug release kinetic was applied to calculate the strength of drug-support interactions. The in vitro cell study was performed on SKBR3 cancer cells and obtained results demonstrated that the modification of the mesoporous silica material by grafted polar/nonpolar groups may significantly affect the compatibility of this material with cells, drug release from this material and subsequent biological activity of PEM.

• MeSH
• koncentrace vodíkových iontů MeSH
• léky s prodlouženým účinkem chemie   farmakokinetika   farmakologie   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   metabolismus   patologie   MeSH
• oxid křemičitý * chemie   farmakokinetika   farmakologie   MeSH
• pemetrexed * chemie   farmakokinetika   farmakologie   MeSH
• povrchové vlastnosti MeSH
• protinádorové látky * chemie   farmakokinetika   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Gas chromatography (GC) is a commonly used technique in amino acid analysis (AAA). However, one of the requirements of the application of GC for AAA is a need for the polar analytes to be converted into their volatile, thermally stable derivatives. In the last two decades, alkyl chloroformates have become attractive derivatization reagents. The reagents react immediately with most amino acid functional groups in aqueous matrices and the process can easily be coupled with liquid-liquid extraction of the resulting less-polar derivatives into immiscible organic phase. Here, we describe a simple protocol for in situ derivatization of amino acids with heptafluorobutyl chloroformate followed by subsequent chiral as well as nonchiral GC/mass spectrometric analysis on a respective nonpolar fused silica and an enantioselective Chirasil-Val capillary column.

• MeSH
• aminokyseliny analýza   chemie   MeSH
• chromatografie plynová metody   MeSH
• fluorokarbony chemie   MeSH
• formiáty chemie   MeSH
• lidé MeSH
• metody pro přípravu analytických vzorků MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
• referenční standardy MeSH
• stereoizomerie MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Gas chromatography (GC) is a commonly used technique in amino acid analysis (AAA). However, one of the requirements of the application of GC for AAA is a need for the polar analytes to be converted into their volatile, thermally stable derivatives. In the last two decades, alkyl chloroformates (RCFs) have become attractive derivatization reagents. The reagents react immediately with most amino acid functional groups in aqueous matrices, and the process can easily be coupled with liquid-liquid extraction of the resulting less polar derivatives into immiscible organic phase. Here we describe a simple protocol for in situ derivatization of amino acids with heptafluorobutyl chloroformate (HFBCF) followed by subsequent chiral as well as nonchiral GC/MS (mass spectrometric) analysis on a respective nonpolar fused silica and an enantioselective Chirasil-Val capillary column.

• MeSH
• aminokyseliny krev   chemie   izolace a purifikace   MeSH
• deuterium analýza   chemie   MeSH
• extrakce kapalina-kapalina přístrojové vybavení   metody   MeSH
• fluorokarbony chemie   MeSH
• formiáty chemie   MeSH
• izotopy uhlíku analýza   chemie   MeSH
• kalibrace MeSH
• lidé MeSH
• plynová chromatografie s hmotnostně spektrometrickou detekcí přístrojové vybavení   metody   MeSH
• stereoizomerie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Seven retention models have been selected to describe a dual-retention behavior of ten dopamine-related compounds on polymer-based monolithic stationary phase with zwitterion sulfobetaine functionality. Regression quality, as well as a statistical significance of individual regression parameters, have been evaluated. Better regression performance showed two four-parameter models when compared to three-parameter models. On the other hand, limited number of experimental points disqualified statistical robustness of four-parameter models. Among three-parameter models, retention description introduced by Horváth and Liang provided comparable quality of regression at significantly improved robustness. Multivariate analysis of the best three-parameter models provided the description of physicochemical properties of dopamine precursors and metabolites. Principal component analysis and logistic regression allowed structural characterization of dopamine-related compounds based solely on regression parameters extracted from an isocratic elution data. Both polarity and type of functional groups has been correctly assigned for 3-methoxytyramine that has not been part of an evaluation study. Among applied dual-retention models, Horváth´s model, initially developed to describe a retention of ionic compounds on nonpolar stationary phases, provided robust regression of experimental data and allowed an extraction of structural characteristics of dopamine-related compounds.

• MeSH
• betain analogy a deriváty   chemie   MeSH
• chemické modely * MeSH
• dopamin analogy a deriváty   chemie   MeSH
• molekulární struktura MeSH
• polymery chemie   MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• biochemie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biochemie

• MeSH
• biologie buňky MeSH
• molekulární biologie MeSH
• Publikační typ
• monografie MeSH

• Konspekt
• Biochemie. Molekulární biologie. Biofyzika
• NLK Obory
• biologie
• cytologie, klinická cytologie