In this work, the combination of an immobilized enzyme microreactor (IMER) based on the clinically important isoform cytochrome P450 2C9 (CYP2C9) with capillary electrophoresis (CE) is presented. The CYP2C9 was attached to magnetic SiMAG-carboxyl microparticles using the carbodiimide method. The formation of an IMER in the inlet part of the separation capillary was ensured by two permanent magnets fixed in a cassette from the CE apparatus in the repulsive arrangement. The resulting on-line system provides an integration of enzyme reaction mixing and incubation, reaction products separation, detection and quantification into a single fully automated procedure with the possibility of repetitive use of the enzyme and minuscule amounts of reactant consumption. The on-line kinetic and inhibition studies of CYP2C9's reaction with diclofenac as a model substrate and sulfaphenazole as a model inhibitor were conducted in order to demonstrate its practical applicability. Values of the apparent Michalis-Menten constant, apparent maximum reaction velocity, Hill coefficient, apparent inhibition constant and half-maximal inhibition concentration were determined on the basis of the calculation of the effective substrate and inhibitor concentrations inside the capillary IMER using a model described by the Hagen-Poisseulle law and a novel enhanced model that reflects the influence of the reactants' diffusion during the injection process.
- MeSH
- bioreaktory MeSH
- difuze MeSH
- diklofenak chemie MeSH
- elektroforéza kapilární * MeSH
- enzymy imobilizované metabolismus MeSH
- kinetika MeSH
- objevování léků přístrojové vybavení metody MeSH
- systém (enzymů) cytochromů P-450 chemie metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Anthropogenic pollutants and in particular pharmaceutical residues are a potential risk for potable water where they are found in increasing concentrations. Different environmental effects could already be linked to the presence of pharmaceuticals in surface waters even for low concentrations. Many pharmaceuticals withstand conventional water treatment technologies. Consequently, there is a need for new water purification techniques. Advanced oxidation processes (AOP), and especially plasmas with their ability to create reactive species directly in water, may offer a promising solution. We developed a plasma reactor with a coaxial geometry to generate large volume corona discharges directly in water and investigated the degradation of seven recalcitrant pharmaceuticals (carbamazepine, diatrizoate, diazepam, diclofenac, ibuprofen, 17α-ethinylestradiol, trimethoprim). For most substances we observed decomposition rates from 45% to 99% for treatment times of 15-66 min. Especially ethinylestradiol and diclofenac were readily decomposed. As an inherent advantage of the method, we found no acidification and only an insignificant increase in nitrate/nitrite concentrations below legal limits for the treatment. Studies on the basic plasma chemical processes for the model system of phenol showed that the degradation is primarily caused by hydroxyl radicals.
- MeSH
- chemické látky znečišťující vodu chemie MeSH
- čištění vody metody MeSH
- diatrizoát chemie MeSH
- diazepam chemie MeSH
- diklofenak chemie MeSH
- ethinylestradiol chemie MeSH
- ibuprofen chemie MeSH
- karbamazepin chemie MeSH
- monitorování životního prostředí MeSH
- odpad tekutý - odstraňování metody MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Particles preparation from biodegradable polymers as carriers for the controlled release of drugs has been the focus of many investigations and the subject of a growing field of research in recent years. The aim of this study was to develop and optimize the preparation of oxycellulose beads containing diclofenac sodium as a model drug. Particle size, surface, drug content and encapsulation efficiency were evaluated, drug dissolution profiles were measured and drug release mechanism estimated. The prepared oxycellulose beads were uniform in size with encapsulation efficiency ranging from 53.2 to 74.9%. The lower temperature of the crosslinking solution and its saturation with diclofenac sodium increased the encapsulation efficiency, especially when both parameters were combined. The application of ultrasound had a negative effect on drug encapsulation. The dissolution of diclofenac sodium in pH 1.2 was close to zero as its solubility in this medium is very limited. The drug release in pH 6.8 lasted from 10 to 16 h showing biphasic behavior with a significant lag time. T1/2 decreased with increasing encapsulation efficiency and ultrasound application. Diclofenac sodium was released from the prepared oxycellulose particles by diffusion as well as by erosion process; ahigh correlation was found with zero order kinetics.
- MeSH
- antiflogistika nesteroidní chemie MeSH
- chemie farmaceutická MeSH
- chlorid vápenatý chemie MeSH
- difuze MeSH
- diklofenak chemie MeSH
- farmaceutická technologie metody MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- léky s prodlouženým účinkem MeSH
- methylcelulosa analogy a deriváty chemie MeSH
- nosiče léků * MeSH
- povrchové vlastnosti MeSH
- reagencia zkříženě vázaná chemie MeSH
- rozpustnost MeSH
- teplota MeSH
- ultrazvuk MeSH
- velikost částic MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
NIR spektroskopie společně s vícerozměrnou analýzou dat se použila k analýze hydrátů diklofenaku sodné soli připravených z nevodných rozpouštědel tetrahydrofuranu a methanolu za standardních laboratorních podmínek při 20 °C a RH < 60 %. Potvrdilo se, že pomocí vyvinutého PLS regresního modelu lze sledovat proces vzniku hydrátů. Dále se zjistilo, že při přípravě lékové formy využívající impregnaci na pevný nosič z nevodných rozpouštědel vzniká hydratovaná forma diklofenaku sodné soli, což se výsledně projevuje až dvojnásobným zpomalením uvolňování léčiva z tablet. NIR spektroskopie se zde potvrdila jako jedna z účinných PAT (process analytical technology) metod.
NIR spectroscopy together with multivariate data analysis were used to analyze the hydrates of diclofenac sodium prepared from the non-aqueous solvents tetrahydrofuran and methanol under standard laboratory conditions at 20 °C and relative humidity less than 60%. It was confirmed that the developed PLS regression model can monitor the process of formation of hydrates. It was also found that the hydrated form of diclofenac sodium arises during the preparation of the dosage form the using technology of impregnating the solid carrier by non-aqueous solvents, which resulted in reducing of the drug release rate from prepared tablets up to twice. NIR spectroscopy was confirmed as one of the effective PAT (Process Analytical Technology) methods.
- MeSH
- antiflogistika nesteroidní * chemie MeSH
- blízká infračervená spektroskopie * metody přístrojové vybavení využití MeSH
- chemie analytická MeSH
- diklofenak * chemie MeSH
- farmaceutická technologie MeSH
- inhibitory cyklooxygenasy MeSH
- lidé MeSH
- metody pro přípravu analytických vzorků MeSH
- příprava léků * MeSH
- regresní analýza MeSH
- Check Tag
- lidé MeSH
The aim of this study was to develop novel hydrogel-based beads and characterize their potential to deliver and release a drug exhibiting pH-dependent solubility into distal parts of gastrointestinal (GI) tract. Oxycellulose beads containing diclofenac sodium as a model drug were prepared by the ionotropic external gelation technique using calcium chloride solution as the cross-linking medium. Resulting beads were characterized in terms of particle shape and size, encapsulation efficacy, swelling ability and in vitro drug release. Also, potential drug-polymer interactions were evaluated using Fourier transform infrared spectroscopy. The particle size was found to be 0.92-0.96 mm for inactive (oxycellulose only) and 1.47-1.60 mm for active (oxycellulose-diclofenac sodium) beads, respectively. In all cases, the sphericity factor was between 0.70 and 0.81 with higher values observed for samples containing higher polymer and drug concentrations. The swelling of inactive beads was found to be strongly influenced by the pH and composition (i.e. Na(+) concentration) of the selected media (simulated gastric fluid vs. phosphate buffer pH 6.8). The encapsulation efficiency of the prepared particles ranged from 58% to 65%. Results of dissolution tests showed that the drug loading inside of the particles influenced the rate of its release. In general, prepared particles were able to release the drug within 12-16 h after a lag time of 4 h. Fickian diffusion was found as the predominant drug release mechanism. Thus, this novel particulate system showed a good potential to deliver drugs specifically to the distal parts of the human GI tract.
- MeSH
- antiflogistika nesteroidní chemie MeSH
- chemické modely MeSH
- chemie farmaceutická MeSH
- difuze MeSH
- diklofenak chemie MeSH
- farmaceutická technologie metody MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- léky s prodlouženým účinkem MeSH
- methylcelulosa analogy a deriváty chemie MeSH
- nosiče léků MeSH
- příprava léků MeSH
- pufry MeSH
- rozpustnost MeSH
- spektroskopie infračervená s Fourierovou transformací MeSH
- studie proveditelnosti MeSH
- velikost částic MeSH
- žaludeční šťáva chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Phytoremediation of selected pharmaceuticals (diclofenac, ibuprofen, and acetaminophen) using Armoracia rusticana and Linum usitatissimum cell cultures and by hydroponically cultivated Lupinus albus, Hordeum vulgaris, and Phragmites australis plants in laboratory conditions is described. During in vitro experiments, the best results for acetaminophen were achieved using Armoracia rusticana hairy root cultures, where 100% of the starting amount was removed from the media during eight days. Total removal of ibuprofen and diclofenac was achieved using a Linum usitatissimum suspension culture after one and six days, respectively. In the hydroponic arrangement, the best results were achieved for Lupinus, where acetaminophen was totally removed from media during two or four days in concentrations of 0.1 or 0.2 mM, respectively. The best effectiveness of ibuprofen removal (50% of starting amount) was found in case of Phragmites. Effectiveness of all tested plants for diclofenac removal was low. The best removal was achieved using Phragmites in the case of 0.2 mM concentration-67% of the starting amount and Hordeum for 0.1 mM starting concentration, 56%.
- MeSH
- biodegradace účinky léků MeSH
- diklofenak chemie izolace a purifikace toxicita MeSH
- hydroponie MeSH
- ibuprofen chemie izolace a purifikace toxicita MeSH
- léčivé přípravky chemie izolace a purifikace MeSH
- paracetamol chemie izolace a purifikace toxicita MeSH
- rostliny účinky léků metabolismus MeSH
- testy toxicity MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The purpose of this experimental work was the development of hydrophilic-lipophilic matrix tablets for controlled release of slightly soluble drug represented here by diclofenac sodium (DS). Drug dissolution profile optimization provided by soluble filler was studied. Matrix tablets were based on cetyl alcohol as the lipophilic carrier, povidone as the gel-forming agent, and common soluble filler, that is lactose or sucrose of different particle size. Physical properties of tablets prepared by melt granulation and drug release in a phosphate buffer of pH 6.8 were evaluated. In vitro studies showed that used filler type, filler to povidone ratio and sucrose particle size influenced the drug release rate. DS dissolution profile could be changed within a wide range from about 50% per 24 hours to almost 100% in 10 hours. The release constant values confirmed that DS was released from matrices by the diffusion and anomalous transport. The influence of sucrose particle size on the drug release rate was observed. As the particle size decreased, the drug release increased significantly and its dissolution profile became more uniform. Soluble fillers participated in the pore-forming process according to their solubility and particle size. Formulations containing 100 mg of the drug, 80 mg of cetyl alcohol, 40 mg of povidone, and 80 mg of either lactose or sucrose (particle size 250-125 microm) were considered optimal for 24-hour lasting dissolution of DS.
- MeSH
- antiflogistika nesteroidní aplikace a dávkování chemie MeSH
- časové faktory MeSH
- diklofenak aplikace a dávkování chemie MeSH
- laktosa chemie MeSH
- léky s prodlouženým účinkem MeSH
- mastné alkoholy chemie MeSH
- nosiče léků chemie MeSH
- pomocné látky chemie MeSH
- povidon chemie MeSH
- rozpustnost MeSH
- sacharosa chemie MeSH
- tablety MeSH
- velikost částic MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In this study, the interaction of diclofenac (Dic) with cationic surfactant cetyltrimethylammonium bromide (CTAB) was investigated. The effect of cationic micelles on solubilization of diclofenac in aqueous micellar solution was studied at pH 6.8, 29 °C and various drug concentrations. The binding of diclofenac to CTAB micelles was accompanied by a batochromic shift in the drug absorption spectra. The solubility of diclofenac increased with increasing surfactant concentration as a consequence of the association between the drug and micelles. From the results, the binding constants Kb, was obtained. By using the pseudo-phase model, the partition coefficient between the bulk water and CTAB micelles, Kx, and the Gibbs energy of binding were calculated. The value of binding constant and partition coefficient are increased by increasing of diclofenac concentration.
The major aim of this work is to demonstrate the applicability of micellar electrokinetic capillary chromatography with SDS based pseudostationary phase for the screening of cytochrome P450 inhibitors. In contrast with the other capillary electrophoresis modes the cytochrome P450 reaction mixture thus could be used for the analysis without any pre-treatment. Cytochrome P450 2C9, one of the most important isoforms in human liver, was chosen as a model example for this study in combination with diclofenac as a probe substrate. The inhibitory effect on the given cytochrome P450 reaction was evaluated for two inhibitors with different inhibition potential - strong inhibitor sulfaphenazole and moderate inhibitor ketoconazole. As a result 50% inhibitory concentrations IC(50) and inhibition constants K(i) were evaluated; their values for both inhibitors were in a good agreement with the literature data determined by different methods.
- MeSH
- aromatické hydroxylasy antagonisté a inhibitory chemie MeSH
- chromatografie micelární elektrokinetická kapilární metody MeSH
- diklofenak farmakologie chemie MeSH
- financování organizované MeSH
- inhibitory cytochromu P450 MeSH
- ketokonazol farmakologie chemie MeSH
- lidé MeSH
- molekulární struktura MeSH
- reprodukovatelnost výsledků MeSH
- sulfafenazol farmakologie chemie MeSH
- systém (enzymů) cytochromů P-450 chemie MeSH
- Check Tag
- lidé MeSH
Enzyme activities of the CYP enzymes (CYP3A4, CYP2C9 and CYP2A6) were determined using classical substrates (testosterone, diclofenac and coumarin, respectively) as well as with luminogenic or fluorogenic substrates in micromethod arrangement. The luciferin-based luminogenic substrates for CYP3A4 and CYP2C9 as well as coumarin in micromethod for assay of CYP2A6 activity gave results well comparable with the classical methods with determination of reaction products by the HPLC.
- MeSH
- aromatické hydroxylasy analýza MeSH
- cytochrom P-450 CYP3A MeSH
- diklofenak chemie MeSH
- kumariny chemie MeSH
- lidé MeSH
- oxygenasy se smíšenou funkcí analýza MeSH
- systém (enzymů) cytochromů P-450 analýza MeSH
- testosteron chemie MeSH
- vysokoúčinná kapalinová chromatografie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
