Complexation of the Non-steroidal Anti-inflammatory Drug Loxoprofen with Modified and Unmodified β-Cyclodextrins

The inclusion complex of the anti-inflammatory drug, loxoprofen, with -cyclodextrin-(CD), sulfated -CD, and glycerol ether -CD was studied by UV-VIS absorption and ¹H-NMR spectroscopy in solution. The inclusion complex of loxoprofen with -CDs was prepared by freeze-drying, and then characterized in the solid state by thermal analysis, X-ray diffraction, FT-IR and FT-Raman spectroscopy, and scanning electron microscopy (SEM). Furthermore, a physical mixture of loxoprofen/-CD (1/1, mol-%) in the solid state was also characterized. The solubility of the loxoprofen increased on addition of -CDs. The solubility enhancement of the loxoprofen with -CDs is in the following order: glycerol ether -CD > sulfated -CD > -CD.     

Kinetics of ligand exchange of aminoacid anions in the ternary complexes of copper(II) and hydroxyethyldenediphosphonic acid

The kinetics of the chemical exchange of some aminoacid anions in ternary complexes of copper(II) and hydroxyethylidenediphosphonic acid has been studied by a nuclear magnetic relaxation method. Rate constants of the chemical exchange have been determined and some suggestions concerning the structure of the complexes have been made.

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(II) . .

     

Solubility Study of Nimodipine Inclusion Complexation with α- and β-Cyclodextrin and some Substituted Cyclodextrins

The solubility of nimodipine was measured in aqueous solutions of the following cyclodextrins: -cyclodextrin (-CD), hydroxypropyl--CD (HP--CD), -cyclodextrin (-CD), random substituted methyl--CD (M--CD), three hydroxypropyl--CDs (HP--CD) with mutually different average degree of substitution, and hydroxypropyl--cyclodextrin (HP--CD). From the determined linear solubility diagrams the values of the binding constant K₁₁ of the inclusion complexes of nimodipine with the respective CDs were evaluated. The -CDs efficiently solubilized sparingly soluble nimodipine, the highest value of K₁₁ was found for M--CD (1680 M^-1), followed by -CD (550 M^-1) and HP--CDs, where the higher degree of substitution lowered K₁₁. Only slight solubilization of nimodipine was observed in the solutions of the -CDs and HP--CD.     

Flammability characterized by flash-ignition Temper-atures

The effects of the experimental conditions (sample size, heating rate, static and dynamic atmosphere) were studied on the value of the flash-ignition temperature (T _i) obtained with a modified derivatograph able to measureT _i simultaneously with the TG, DTG, DTA and T curves. The effects of various parameters are discussed and the optimum conditions determined.T _i for bleached cotton fibre was found to be 270±1 °C.

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Zusammenfassung Es wurde der Einfluß experimenteller Bedingungen (Probengröße, Aufheizgeschwindigkeit, stehende und bewegte Atmosphäre) auf den Wert der Entzündungstemperatur (T _i) untersucht, welche mittels eines zur gleichzeitigen Messung vonT _i sowie der TG, DTG, DTA und T-kurven modifizierten Derivatographen bestimmt wurde. Der Einfluß verschiedener Parameter wurde besprochen und Optimumbedingungen festgestellt. Für gebleichte Wolle wurde einT _i-Wert von 270±1 °C gemessen.

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( , , ) - (i), , _i , , T-. . , t _i 270±1°.

     

Synthesis of Some Allyl-β-Cyclodextrin Derivatives and their Properties as Capillary GC Stationary Phases

Summary Three -Cyclodextrin derivatives (-CDs) were synthesized by substituting the 2,6-OH groups of -CD with allyl groups and the 3-OH groups with three different acyl groups (valeryl, heptanonyl, octanoyl). The chromatographic properties of these -CDs as stationary phases for capillary gas chromatography (CGC) were studied. The test results showed that the three -CDs possessed good coating properties and that the capillary columns coated with them exhibited high column efficiency. These -CDs can separate not only the disubstituted benzene isomers but also some racemic compounds.     

Thermal stability of elastomers

Thermal transitions of elastomers are classified and problems concerning their stability are discussed. It is concluded that in the case of general-purpose elastomers no simple correlation exists between the energy of the bonds in the skeleton of a chain and their thermal stability. This also holds for the parameters of the physical structure of the chains. A high tendency to cross-linking, a high concentration of cross-links and their chemical structure give rise to a more perceptible effect.

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Zusammenfassung Thermische Umwandlungen von Elastomeren werden klassifiziert und mit der StabilitÄt von Elastomeren zusammenhÄngende Probleme diskutiert. Es wird gefolgert, da\ bei Elastomeren für allgemeine Verwendungszwecke keine einfache Korrelation zwischen der Energie der Bindungen im Kettengerüst und der thermischen StabilitÄt besteht. Das gilt auch für die Parameter der physikalischen Struktur der Ketten. Der Effekt einer starken Neigung zur Vernetzung, der Netwerkdichte und der chemischen Konstitution der Netzwerkbrücken ist dagegen augenscheinlicher.

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. , . . , , .

     

Carbon monoxide hydrocondensation on iron catalysts prepared from metal carbonyl compounds

The iron/alumina catalysts prepared by the impregnation of Fe(CO)₅ on the support have properties quite different from those of the conventional catalysts in the CO+H₂ reaction. However, the preparation procedure or the activation of the solid has a decisive effect on the activity, selectivity and stability.

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Fe(CO)₅ , , CO+H₂. , , .

     

Scanning electron microscopic study of an industrial catalyst for ammonia synthesis

The surface topography and elemental composition of the near-surface layers of a reduced passivated catalyst for ammonia synthesis have been studied on a scanning electron microscope in the initial state and after high-temperature oxygen treatment as well as removal of the alkali promoter.

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CA-IB , .

     

Interactions of Nabumetone with Cyclodextrins in Solution and in the Solid State

The interactions of nabumetone (NAB) with -cyclodextrin (-CD) and-cyclodextrin (-CD) were studied in aqueous solution by meansof phase-solubility analysis. Solid dispersions of NAB with -cyclodextrin(-CD), -cyclodextrin (-CD), methyl- (M-CD),hydroxypropyl-cyclodextrin (HP-CD) were prepared by coevaporationand kneading and also by coprecipitation in the case of -CD. X-ray diffractometry, thermal analysis and infrared spectroscopy (FTIR) were used to study the possibility of complexation of the drug with the different cyclodextrins. Solid dispersions of nabumetone with -CD showed a remarkable improvement in the dissolution rate of nabumetone.     

On the mechanism of propylene epoxidation catalyzed by molybdenum naphthenate

The mechanism of the catalytic epoxidation of propylene with -phenylethyl hydroperoxide has been investigated. The epoxidation step is a molecular interaction between propylene and a complex formed from hydroperoxide and catalyst, while part of side products is formed in free radical reactions. This mechanism is valid for the kinetics of both epoxidation and catalytic decomposition of hydroperoxide.

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. — . . .

     

New cardenolides from the leaves ofGomphocarpus fruticosus

Two new glycosides, gomphotin (1) and gomphotoxin (13), and also the known gomphoside (9) have been isolated from the leaves ofGomophocarpus fruticosus. Compounds (1) and (9) contain a 4,6-dideoxyhexosulose residue as the sugar component, and (13) a 6-deoxyhexosulose, which are attached to glycolic OH groups of the aglycons by 3-O-1,2-O-2 (9, 13) and 3-O-1,4-O-2 (1) acetal-ketal bonds. The structures of the new compounds are represented by the names (3-O-1,4-O-2)-(2,3-dihydroxy-4, 6dideoxyhexulosido)-14-hydroxy-5-card-20(22)-enolide* (1) and (3-O-1,2-O-2)-(2,3,4-trihydroxy-6-deoxyhexulosido)-14-hydroxy-5-card-20(22)-enolide* (13).State Scientific Center for Drugs of the Ministry of Health and the National Academy of Sciences of the Ukraine, Kharkov, fax 441118. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 824–832, November–December, 1995. Original article submitted May 22, 1995.     

Effects of Modified β-Cyclodextrins on the Hydrolysis Reaction of p-Nitrophenyl α-Methoxyphenylacetate

Effects of -cyclodextrin (-CD) 1and its derivatives 2–7 on the deacylationreaction of p-nitrophenyl (R or S)--methoxyphenylacetatewere studied. The-CD derivatives used were6--D-glucosyl--CD 2, sulfated-CD (7–11 sulfate groups/CD ring) 3,dimethylated -CD 4, carboxymethylated-CD (3.5 carboxymethyl groups/CD ring) 5,2-tri(2-hydroxypropyl)--CD 6, and-CD appended on poly(allylamine) 7. Therate constant (k ^CD) of thesubstrate/-CD complexes and the formationconstants (K) of the complexes were determinedfrom the dependence of the pseudo-first order rateconstants of the deacylation reaction on theconcentration of -CDs. The order ofk ^CD for the R-enantiomer at pH8.0 is 45H₂O3 6 1 2 7, whilethat for the S-enantiomer is 4 5 6H₂O 1 2 3 7: H₂O denotes the rate in theabsence of -CDs. The order of K values is3 7 6 2 1 4 5. This work indicates that, though thesecondary hydroxyl groups of -CD play criticalroles in the deacylation reactions of the esterscomplexed with -CDs, the reactivity of theester/-CD complexes depends highly on thenature of the substituents at the secondary face of-CD. It also suggests that the substratesinserted from the secondary side as well as theprimary side of -CD of poly(allylamine)-bound-CD undergo the reaction by attack of aminogroups on the polymer chain.     

Fluorine containing β-lactones

Summary Ring opening of -trifluoromethyl- -methyl- -propiolactone is unidirectional and leads to derivatives of -trifluoromethyl- -hydroxybutyric acid.     

Preparation and Characterization of Branched β-Cyclodextrins Having Manno-Oligosaccharide Side Chains Derived from Yeast Mannan and Study of Their Functions

Branched -cyclodextrins (-CDs) having manno-oligosaccharide side chains were investigated. Three kinds of monobranched -CDs and five kinds of dibranched -CDs were chemically synthesized using the trichloroacetimidate method. Their structures were analyzed by HPLC, MS, and NMR spectroscopies. The specific interaction between those compounds and mannose-binding lectins (Concanavalin A and Pisum sativum agglutinin) was investigated by inhibition tests of hemagglutinating activity and by using an optical biosensor of the IAsys apparatus with a resonant mirror detector. The results showed that all branched -CDs interactedwith lectins. The binding affinity was 6¹,6⁴-(Man₃)₂- 6¹,6⁴-(Man₂)₂- > 6¹,6⁴-(Man₄)₂--CD when the derivatives were compared on the basis of side chain length and 6¹,6³- 6¹,6⁴- > 6¹,6²-(Man₂)₂--CD when compared on the basis of side chain position.     

Reaction of methylmagnesium iodide with steroid keto oxides

Summary The reaction of the 3-acetate of the 20-ketal of 16,17-oxido-⁵-pregnenol-3-one-20 with methylmagnesium iodide and subsequent hydrolysis of the reaction product yielded 16-methyl-⁵-pregnenediol-3 –17-one –20. 18-Nor-17-methyl-17-iso-^5.11-pregnadienediol-3,16-one-20 was formed as a by-product.     

Triterpene glycosides ofAstragalus and their genins XLV. The chemical transformation of cycloartanes 1. Synthesis of 25-norglycosides

Literature information is given on the current state of the study of the chemical transformation of cycloartane triterpenoids. A method has been developed for the transformation of the genin part of glycosides of 20,24-epoxycycloartan-25-ols with retention of the carbohydrate constituents. Three 25-norglycosides have been synthesized from natural cyclosieversigenin glycosides, namely 16-acetoxy-3,6-dihydroxy-20R,25-norcycloartan-20,24-olide 3-O-[O--L-arabinopyranosyl-(12)--D-xylopyranoside] 6-O--D-xylopyranoside (VIII), sodium 3,6,16,20-tetrahydroxy-20R,25-norcycloartan-24-oate 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XII), and 20R,25-norcycloartane-3,6,16,20,24-pentaol 6-O--D-glucopyranoside 3-O--D-xylopyranoside (XIII).Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 710–718, September–October, 1993.     

Nature of extended defects of CuO

For the first time, using high-resolution electron microscopy, extended defects (twins, screw dislocations and microdistortions) of disperse CuO have been found. Their structure is described.

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CuO -, .

     

Über die Darstellung von 3β, 16α-und 3β, 16β-Diacetoxy-5α-pregnan-20-on

Zusammenfassung Die Synthese von 3, 16-Diacetoxy-5 -pregnan-20-on (VI) aus 3-Acetoxy-5 -pregn-16-en-20-on und eine verbesserte Darstellung von 3, 16-Diacetoxy-5 -pregnan-20-on (III) aus 3-Acetoxy-pregna-5, 16-dien-20-on werden beschrieben.     

Catalytic oxidation of carbon monoxide by oxygen and nitrogen oxides on a copper-chromium oxide catalyst

The kinetics of CO oxidation by O₂, NO and NO₂ has been studied on a Cu–Cr-oxide catalyst. A comparison with the kinetics of the CO–N₂O interaction has been made. In all cases the reaction rate is described by the equation:r=k p _CO ¹ P _0x ⁰ . The oxidation of CO has been studied in the presence of different oxidants in the reaction mixture.

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CO , . CO . CO . CO .

     

Direct reading thermometric analysis

According to the direct reading thermometric method the concentration of the component to be determined is established from the temperature variation of the sample solution obtained on adding to it an excess of a reagent which reacts selectively with the respective component. Under suitably chosen experimental conditions the concentration of the respective component is determined from a single measured value. Since the established measurement technique requires little manual work and the respective components may be determined from the sample solution directly without any separations, the method in its present form is chiefly suitable for rapid serial analyses.

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Zusammenfassung Bei der thermometrischen Methode mit Direktablesung wird die Konzentration der gesuchten Komponente aus der Temperaturänderung der Probelösung bestimmt, die nach Zugabe eines Überschusses von einem selektiv reagierenden Reagens wahrnehmbar ist.Unter geeigneten Versuchsbedingungen kann man die Konzentration der gesuchten Komponente aus einem einzigen Meßwert, nämlich der Temperaturänderung der Probelösung bestimmen. Da die ausgearbeitete Meßtechnologie wenig Arbeit erfordert und die gesuchten Komponenten ohne jede Trennung direkt bestimmt werden können, ist die Methode in ihrer jetzigen Ausführungsart hauptsächlich zu betriebsmäßigen Serien-Schnellanalysen geeignet.

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Résumé Selon la méthode thermométrique à lecture directe, on détermine la concentration du constituant cherché d'après la variation de température de la solution échantillon que l'on additionne d'un excès de réactif sélectif de celui-ci. Dans les conditions expérimentales appropriées, une seule mesure suffit pour déterminer la concentration du constituant cherché. Comme la technique de mesure qui a été mise au point demande peu de travail et comme on peut doser sans aucune séparation les constituants étudiés, la méthode dans sa forme actuelle se prête en premier lieu aux dosages en séries industriels.

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