physicochemical parameters
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Garlic is a well-known example of natural self-defence system consisting of an inactive substrate (alliin) and enzyme (alliinase) which, when combined, produce highly antimicrobial allicin. Increase of alliinase stability and its activity are of paramount importance in various applications relying on its use for in-situ synthesis of allicin or its analogues, e.g., pulmonary drug delivery, treatment of superficial injuries, or urease inhibitors in fertilizers. Here, we discuss the effect of temperature, pH, buffers, salts, and additives, i.e. antioxidants, chelating agents, reducing agents and cosolvents, on the stability and the activity of alliinase extracted from garlic. The effects of the storage temperature and relative humidity on the stability of lyophilized alliinase was demonstrated. A combination of the short half-life, high reactivity and non-specificity to particular proteins are reasons most bacteria cannot deal with allicin's mode of action and develop effective defence mechanism, which could be the key to sustainable drug design addressing serious problems with escalating emergence of multidrug-resistant (MDR) bacterial strains.
- MeSH
- antibakteriální látky farmakologie MeSH
- Bacteria účinky léků ultrastruktura MeSH
- biokatalýza účinky léků MeSH
- časové faktory MeSH
- česnek enzymologie MeSH
- chemické jevy * MeSH
- disulfidy chemie metabolismus MeSH
- kinetika MeSH
- koncentrace vodíkových iontů MeSH
- kyseliny sulfinové chemie metabolismus MeSH
- lyasy štěpící vazby C-S metabolismus MeSH
- lyofilizace MeSH
- mikrobiální testy citlivosti MeSH
- mikrobiální viabilita účinky léků MeSH
- pufry MeSH
- stabilita enzymů účinky léků MeSH
- stereoizomerie MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
V predloženej práci prezentujeme výsledky štúdia fyzikálno-chemických vlastností derivátov kyseliny 2-, 3-, 4-alkoxyfenylkarbámovej, ktorých štruktúra sa odlišuje rozdielne substituovaným N-fenylpiperazín-1-ylovým fragmentom, ktorý tvorí bázickú časť molekuly. V rámci štúdia bola vykonaná elementárna analýza, stanovili sme teplotu topenia, rozpustnosť, povrchovú aktivitu, disociačnú konštantu ako aj parametre lipofility, t.j. rozdeľovací koeficient, kapacitný faktor pomocou vysokoúčinnej kvapalinovej chromatografie a hodnoty RM z rozdeľovacej chromatografie na tenkej vrstve.
The paper presents the study of some physicochemical properties of 2-, 3-, 4-alkoxy- phenylcarbamic acid derivatives with various substituted N-phenylpiperazin-1-yl moiety in the basic part of the molecule. Elemental analysis, melting point, solubility, surface activity, dissociation constant and some lipophilicity parameters i.e. – partition coefficient, capacity factor obtained from HPLC, and RM values from reversed-phase thin-layer chromatography were determined.
The purpose of this study was to specify critical parameters (physicochemical characteristics) of drug substance that can affect dissolution profile/dissolution rate of the final drug product manufactured by validated procedure from various batches of the same drug substance received from different suppliers. The target was to design a sufficiently robust drug substance specification allowing to obtain a satisfactory drug product. For this reason, five batches of the drug substance and five samples of the final peroral drug products were analysed with the use of solid state analysis methods on the bulk level. Besides polymorphism, particle size distribution, surface area, zeta potential, and water content were identified as important parameters, and the zeta potential and the particle size distribution of the drug substance seem to be critical quality attributes affecting the dissolution rate of the drug substance released from the final peroral drug formulation.
Biochar application is a widely investigated topic nowadays, and precisely described biochar parameters are key information for the understanding of its behaviour in soil and other media. Pore structure and surface properties determine biochar fate. However, there is lack of complex, investigative studies describing the influence of biomass properties and pyrolysis conditions on the pore structure of biochars. The aim of our study was to evaluate a wide range of gathered agriculture residues and elevated pyrolysis temperature on the biochar surface properties and pore composition, predicting biochar behaviour in the soil. The biomass of herbaceous and wood plants was treated by slow pyrolysis, with the final temperature ranging from 400 to 600 °C. Specific surface ranged from 124 to 511 cm2 g-1 at wood biochar and from 3.19 to 192 cm2 g-1 at herbaceous biochar. The main properties influencing biochar pore composition were increasing pyrolysis temperatures and lignin (logarithmically) and ash contents (linearly) of biomass. Increasing lignin contents and pyrolysis temperatures caused the highest biochar micropore volume. The total biochar pore volume was higher of wood biomass (0.08-0.3 cm-3 g-1). Biochars of wood origin were characterised by skeletal density ranging from 1.479 to 2.015 cm3 g-1 and herbaceous ones 1.506-1.943 cm3 g-1, and the envelope density reached 0.982 cm3 g-1 at biochar of wheat grain origin and was generally higher at biochars of herbaceous origin. Density was not pyrolysis temperature dependent.
Práca sa venuje syntéze, overeniu štruktúry a štúdiu fyzikálno-chemických vlastností derivátov aryloxyaminopropanolu, 2-hydroxy-3-[4-(2-fluórfenyl)-piperazín-1-yl]-propyl-4-[(alkoxykarbonyl)amino] benzoátov, ich solí s kyselinou chlorovodíkovou, s jedným až štyrmi atómami uhlíka v alkoxy skupine karbamoylovej skupiny. Štruktúra zlúčenín bola potvrdená elementárnou analýzou, IČ, UV a hmotnostnými spektrami. V rámci štúdia bola stanovená teplota topenia, rozpustnosť, povrchová aktivita, disociačná konštanta, ako aj parametre lipofility, t.j. rozdeľovací koeficient P, hodnoty RM z reverznej chromatografie na tenkej vrstve a retenčný faktor k pomocou vysokoúčinnej kvapalinovej chromatografie.
The paper deals with the synthesis, structure confirmation, and study of physicochemical properties of some aryloxyaminopropanol derivatives, compounds of 2-hydroxy-3-[4-(2-fluorophenyl)-piperazine-1-yl]-propyl-4-[(alkoxycarbonyl)amino]benzoates, their salts with hydrochloric acid, with one to four carbon atoms in the alkoxy group of the carbamoyl group. Their structure was confirmed by elemental analysis, IR, UV and mass spectra. The melting point, solubility, surface activity, dissociation constant, and some lipophilicity parameters, i.e. partition coefficient P, RM values from reversed phase thin-layer chromatography, and retention factor k obtained from HPLC of the substances under study were determined.
PURPOSE: The purpose of this study was formulation and optimization of vaginal film formulation containing abacavir (ABC), a potent nucleoside reverse transcriptase inhibitor. METHODS: Vaginal films were prepared by solvent evaporation method using hydroxypropyl methylcellulose (HPMC) blended with polyvinyl pyrrolidone (PVP). Various physicochemical parameters of the prepared films such as drug content, thickness, tensile strength, percentage elongation at break, drug polymer interaction, swelling capacity, folding endurance, bio-adhesion, pH, and moisture content were evaluated with morphological studies. In vitro release study and in vivo release study were also performed. RESULTS: Films exhibited favorable physicochemical properties. The in vitro study showed that HPMC-PVP combination can control the release of abacavir through vaginal films with higher amount of PVP in the formulation resulting in an enhanced drug release rate. During the in vivo study in rabbits, systemic absorption of the drug was noted and the films remained intact for long in vagina without causing any sort of irritations. CONCLUSION: Thus, in a nutshell, the findings of our experimental work indicate that such films can be considered as a novel drug carrier system for the treatment of AIDS and other sexually transmitted diseases (STDs), and are suitable for local as well as systemic effects.
- MeSH
- aplikace intravaginální MeSH
- chemické jevy MeSH
- dideoxynukleosidy aplikace a dávkování farmakokinetika MeSH
- králíci MeSH
- látky proti HIV aplikace a dávkování farmakokinetika MeSH
- lékové formy * MeSH
- nosiče léků aplikace a dávkování chemie MeSH
- příprava léků * MeSH
- uvolňování léčiv * MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
V rámci komplexného štúdia vzťahov medzi chemickou štruktúrou, fyzikálno-chemickými vlastnosťami a biologickou (antiarytmickou, antihypertenzívnou) aktivitou duálne pôsobiacich zlúčenín boli pripravené 1-[3-(Y-alkoxyfenylkarbamoyloxy)-2-hydroxypropyl]-4-(2-?-metylfenyl)piperazíniumchloridy s pracovným označením 7a–7d. Chemická štruktúra príslušných bázických foriem (7a2C–7d2C) a monochloridov (7a–7d) bola potvrdená 1H-NMR, 13C-NMR, MS a IR spektrálnou ako aj elementárnou analýzou. Medzi stanovené základné fyzikálno-chemické charakteristiky patrilo určenie teploty topenia, rozpustnosti v spektre rozpúšťadiel, overenie čistoty (adsorpčná chromatografia na tenkej vrstve), určenie povrchovej aktivity (Traubeho stalagmometrická metóda), acidobázických charakteristík (hodnoty pKa pomocou alkalimetrickej titrácie) a určenie hodnôt log ? s využitím spektrofotometrie v UV/VIS oblasti. Medzi ďalšie experimentálne stanovené parametre patrili lipohydrofilné charakteristiky pomocou chromatografie na tenkej vrstve s obráteným systémom fáz (RM), RP-HPLC (log k’), shake flask metódou stanovené hodnoty rozdeľovacích koeficientov Pexp (resp. log Pexp) v systéme oktán-1-ol/tlmivý fosforečnanový roztok.
1-[3-(Y-Alkoxyphenylcarbamoyloxy)-2-hydroxypropyl]-4-(2-methylphenyl)piperazinium chlorides (labelled as 7a–7d) were prepared within a complex study of the relationships between the chemical structure, physicochemical properties and biological (antiarrhythmic, antihypertensive) activity of dual acting compounds. Chemical structures of basic forms (labelled as 7a2C–7d2C) and appropriate monochlorides (labelled as 7a–7d) were confirmed by 1H-NMR, 13C-NMR, MS and IR spectral and elemental analysis. The estimated physicochemical parameters included the melting point data, solubility profile in various media, purity checking (adsorption thin-layer chromatography), surface activity determination (Traube stalagmometric method), acidobasic characteristics (pKa value determination by alkalimetric titration) as well as the log ? values estimation by UV/VIS spectrophotometry. Other experimental values under consideration were lipohydrophilic characteristics using reversed-phase thin-layer chromatography (RM readouts) RP-HPLC (log k’ data) and the log Pexps estimated in octan-1-ol/phosphate buffer medium.
