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PubMed1976

Spectrophotometric study of complex formation between oxovanadium (IV) and antiamebic drugs.

Complex formation between oxovanadium(IV) and the antiamebic drugs 5, 7-dibromo-8-quinolinol and 5, 7-dichloro-8-quinolinol was studied in the pH 1.5-2.0 range, using ethanol, dioxane-water, and dimethylformamide as solvents. The composition of the formed complexes was determined by more than one procedure. In ethanol and dioxane-water, the 1:1 and 1:2 complexes were formed; in dimethylformamide, the 1:1, 1:2 and 1:3 complexes were formed. The stability constants were computed using two procedures: the molar ratio method and the extrapolation method. The reproducibility or results in satisfactory.

Amebicides↗

PubMed1982

Novel method of derivatization of an amidinourea (lidamidine) for GLC analysis.

A new quantitative GLC method for analysis of lidamidine hydrochloride (I) was developed. The method was based on derivatization of I to 1-(2,6-dimethylphenyl)-4-methylamino-dihydro-1,3,5-triazin-2-one (II) using dimethylformamide dimethylacetal reagent. Compound II was synthesized and characterized by IR, NMR, mass spectrometry, and elemental analysis. The assigned structure was in agreement with characterization analyses. Cyclization of I to a triazinone using dimethylformamide dimethylacetal reagent presented a new route for the preparation of II.

Chemistry, Pharmaceutical↗

PubMed1982

Bioavailability of griseofulvin from tablets in humans and the correlation with its dissolution rate.

Dissolution rates of 10 commercial microsize griseofulvin tablets and one ultramicrosize griseofulvin tablet were preliminarily determined in 18 liters of pH 7.2 phosphate buffer and in 900 ml of 40% dimethylformamide as test media. Addition of dimethylformamide affected the dissolution behavior of the formulations. The products, three microsize and one ultramicrosize, were selected for further studies on the bioavailability in humans and dissolution. Significant differences among the formulations were found in serum levels Cmax, and AUC47.5 hr, but not in AUC infinity and tmax. The maximum difference of Cmax was approximately 40%. The ultramicrosize product showed lower Cmax and serum levels at earlier sampling times than two microsize products. The dissolution rates determined under sink and nonsink conditions without pretreatment significantly correlated with the serum level at 1 hr but not with the other in vivo parameters. Only the dissolution rate determined by the sink method with pretreatment with a small quantity of water (1.0 ml) and plastic beads significantly correlated with serum levels at 3 and 5 hr, Cmax, and AUC 47.5 hr.

Biological Availability↗

PubMed1989

Physicochemical and structural studies of triamterene.

It has been shown by several physicochemical techniques that the existence of different crystal forms of triamterene, as well as the crystalline products from different solvents with distinct differences in melting points, does not necessarily imply polymorphic crystal forms. The crystalline structure for triamterene is reported herein, revealing a N,N-dimethylformamide molecule and a water molecule within the crystal lattice. Triamterene crystallizes in a face-centered orthorhombic space group, Fdd2 (#43), when grown from aqueous solutions of dimethylformamide (N,N-DMF). In addition, the asymmetric unit contains a partially occupied molecule which is situated on a crystallographic twofold axis. Weak hydrogen bonding occurs between atoms O(1) and N(7), with a distance of 2.66 A, O(1) and N(5) with a distance of 2.96 A, O(2) and N(1), at two different symmetry sites of 2.99 A, and N(2) and N(7), with a distance of 2.91 A. The different solvated crystalline triamterene specimens have different melting points depending on organic solvation, water, or both.

Chemical Phenomena↗

PubMed1990

Use of human keratinocyte and fibroblast cultures for toxicity studies of topically applied compounds.

Penetration enhancers are often used as additives in pharmaceutical and dermatological preparations. It should be expected that in many cases penetration enhancers not only enter the stratum corneum but also reach the viable cells of the epidermis and exert a toxic effect. This study focused on a series of well-known compounds that are often used as skin penetration enhancers; namely, ethanol, propylene glycol, dimethylsulfoxide, dimethylformamide, and Brij 96. In order to obtain more insight in the potential skin toxicity of these agents, they were administrated to cultured human keratinocytes and fibroblasts and the following cytotoxicity assays were performed: inhibition of the proliferation of fibroblasts and keratinocytes; inhibition of collagen contraction by fibroblasts; and cell morphology changes in confluent cultures of fibroblasts and keratinocytes. In all assays performed, the same trend was observed: ethanol was the least toxic, propylene glycol, dimethylsulfoxide, and dimethylformamide were moderately potent, and Brij 96 was the most toxic agent. An obvious advantage of the in vitro model presented here is its immediate availability and reproducibility, which allows for the comparison of a large series of topical agents (e.g., penetration enhancers) with respect to their cell toxicity under standardized conditions. However, this single-cell model lacks some of the properties found in intact skin, such as the stratum corneum barrier, and interactions between keratinocytes and other cells, such as Langerhans cells. Hence, extrapolation of these data to in vivo should be done with caution.

Adjuvants, Pharmaceutic↗

PubMed2004

New hydrolyzable pH-responsive cationic polymers for gene delivery: a preliminary study.

Here we want to report the synthesis and the characterization of 2-methylacrylic acid 2-(3-imidazol-1-yl-propionyloxy)ethyl ester (IPEMA), a new methacrylate derivative monomer bearing an hydrolyzable side chain terminated by an imidazole group. The kp/kt(1/2) value for its homopolymerization in N,N-dimethylformamide at 60 degrees C was found to be 0.120 mol(-1/2) x L(1/2) x s(-1/2). The free radical copolymerization of N,N-dimethylaminoethyl methacrylate and this monomer was studied in N,N-dimethylformamide at 60 degrees C, the reactivity ratios of this couple of monomers were determined to be r(DMAEMA) = 1.13 +/- 0.09 and r(IPEMA) = 0.82 +/- 0.09 (using distinct calculation methods). Molecular weights analysis, parallely with refractive index increments measurements, were performed to characterize the obtained polymers. Potentiometric titrations showed the ability of these copolymers to act as a 'proton sponge'. Preliminary study of the copolymers hydrolysis proved that imidazole units could be slowly cleaved from the polymer backbone at 37 degrees C in neutral aqueous buffer. Agarose gel electrophoresis of plasmid DNA/polymer complexes demonstrated the DNA complexing properties of these imidazole-based copolymers.

Cations↗

PubMed1980

Biomonitoring of industrial solvent exposures in workers' alveolar air.

Ten different solvents, viz., toluene, styrene, methylethyl ketone, acetone, dimethylformamide, cyclohexane, n-hexane, methylcyclopentane, 2-methylpentane, and 3-methylpentane were determined in environmental air and in the alveolar air of workers during the work shift. As regards all ten solvents studied, alveolar concentration (Ca) and the difference between environmental concentration (Ci) and alveolar concentration (Ci-Ca), were correlated with environmental concentration. According to the slopes of the regression lines, the ratio between alveolar and environmental concentration (Ca/Ci) and the alveolar retention ((Ci-Ca)/Ci) in the case of all ten solvents studied were complementary, i.e., their sum was equal to unity. The solvents with high solubility in blood, i.e., toluene, styrene, methylethyl ketone, acetone, and dimethylformamide showed a Ca/Ci ratio lower than 0.5 and the solvents with low solubility, i.e., cyclohexane, hexane, and their isomers showed a Ca/Ci ratio higher than 0.5. According to the findings which prove that the alveolar concentration of all solvents studied during the work shift is a function of variations in the environmental concentrations it seems reasonable to suggest the use of alveolar tests for monitoring environmental exposure to solvents during the work shift.

Air Pollutants↗

PubMed1993

Severe hepatic failure occurring with T61 ingestion in an attempted suicide. Early recovery with the use of intravenous infusion of reduced glutathione.

A case of acute hepatic failure following ingestion of the veterinary euthanasia drug T61 is described. Presenting symptoms were drowsiness, disorientation, muscle hypertonia, and upper limb myoclonus, which faded within a few hours. Two days later, acute liver failure occurred, manifested as encephalopathy, jaundice, and a severe coagulopathy. The hepatic damage was thought to be due to the solvent dimethylformamide, which is the only known hepatotoxin included in the preparation utilized in the suicide attempt. High-dose (1.2 g/day) intravenous reduced glutathione was administered, with a rapid improvement of liver function. The patient was discharged after 17 days. Normalization of all liver function tests was achieved within two months. The favorable outcome in this case stands in contrast to the report of a previous case of lethal T61-induced hepatic failure. Although a different amount of dimethylformamide was ingested in each case (0.45 vs 0.60 ml/kg body wt) and individual differences in susceptibility to the effects of the hepatotoxic agent may have played a major role in these two cases, it is not unlikely that the infusion of high doses of glutathione to our patient contributed to her survival and hepatic recovery.

Adult↗

PubMed1984

Fractionation techniques in a hydro-organic environment. II. Acryloyl-morpholine polymers as a matrix for electrophoresis in hydro-organic solvents.

The properties of gels prepared either from acryloyl-morpholine (ACM) or from its mixtures with acrylamide and crosslinked either with bisacrylylpiperazine or with methylenebisacrylamide have been described. ACM-containing gels are compatible with organic solvents. If polymerized in water and dried, they are able to reswell, e.g., in dimethyl sulfoxide or dimethylformamide. If polymerized in presence of dimethylformamide, they form perfectly clear gels, whose mechanical properties are by far superior than those of similar plain polyacrylamide formulations.

Acrylic Resins↗

PubMed1984

Reverse-phase purification and silica gel thin-layer chromatography of porphyrin carboxylic acids.

Thin-layer chromatography on silica gel 60 plates in the solvent N,N-dimethylformamide/methanol/ethylene glycol/glacial acetic acid/1-chlorobutane/chloroform (4/35/6/0.4/18/20 by volume) separates porphyrin carboxylic acids by the number of free carboxyl groups. Coproporphyrins I and III and isocoproporphyrin are separated in 30 min, other porphyrins in 15 min. The N,N-dimethylformamide and acetic acid in the solvent strongly increase porphyrin fluorescence on the plates. Fading and diffusion of the fluorescent patterns is prevented by storage of the plates in the cold and dark without oxygen and with desiccant. In a preliminary step, porphyrins are purified in high yields, concentrated, and deacidified rapidly (2 min) by reverse-phase chromatography on cartridges containing a C18 spacer or on Amberlite XAD-2 columns. The methods are applied to urines of porphyria patients and for following porphyrin ester hydrolysis.

Carboxylic Acids↗

PubMed1985

Detection of a novel cyclooxygenase metabolite produced by human promyelocytic leukemia (HL-60) cells.

Arachidonic acid metabolism via the lipoxygenase pathway was examined in HL-60 cells before and after N,N-dimethylformamide induced differentiation along granulocytic lines. Untreated HL-60 cells produced small amounts of the 5-lipoxygenase products, 5-hydroxy-eicosatetraenoic acid and leukotriene B4 upon stimulation with calcium ionophore A23187. N,N-dimethylformamide treatment, caused a 10 to 20 fold increase in the amount of ionophore A23187-induced 5-lipoxygenase metabolites. An additional, and as yet unidentified arachidonic acid metabolite was routinely observed during reverse-phase high pressure liquid chromatography analyses of lipoxygenase products. Sensitivity to inhibition by less than 10(-7)M indomethacin coupled with other characteristics of its production, strongly suggest the compound is a cyclooxygenase product. The unusual UV absorbance and chromatographic elution pattern, however, suggest that it is not a typical prostaglandin, thromboxane or prostacyclin product.

Arachidonate Lipoxygenases↗

PubMed1987

Synthesis of 2-acetamido-2-deoxy-4-O-(2-O-methyl-beta-D-galactopyranosyl)- D-glucopyranose (N-acetyl-2'-O-methyllactosamine).

1,3,4,6-Tetra-O-acetyl-2-O-methyl-D-galactopyranose, prepared from known methyl 6-O-acetyl-3,4-O-isopropylidene-beta-D-galactopyranoside, was treated with hydrogen bromide in dichloromethane to afford 3,4,6-tri-O-acetl-2-O-methyl-alpha-D-galactopyranosyl bromide. Condensation with benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-alpha-D-glucopyranoside in acetonitrile in the presence of mercuric cyanide gave an approximately 1:1 mixture of benzyl 2-acetamido-3, 6-di-O-benzyl-2-deoxy-4-O-(3,4,6-tri-O-acetyl-2-O-methyl-beta- (8) and -alpha-D-galactopyranosyl)-alpha-D-glucopyranoside. O-Deacetylation and catalytic hydrogenolysis of the benzyl group furnished 2-acetamido-2-deoxy-4-O-(2-O-methyl-beta- and alpha-D-galactopyranosyl)-D-glucopyranose. Alternatively, benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-beta-D- galactopyranosyl-alpha-D-glucopyranoside was treated with tert-butyldiphenyl-chlorosilane in N,N-dimethylformamide, in the presence of imidazole, to give a 6'-O-tert-butyldiphenylsilyl intermediate that was in turn converted into its 3',4'-O-isopropylidene acetal. Methylation with methyl iodide-silver oxide in N,N-dimethylformamide, followed by removal of the silyl and isopropylidene groups gave benzyl 2-acetamido-3,6-di-O-benzyl-2-deoxy-4-O-(2-O-methyl-beta-D- galactopyranosyl)-alpha-D-glucopyranoside, which was further characterized as its triacetate 8.

Amino Sugars↗

PubMed1988

Synthesis of O-alpha-L-fucopyranosyl-(1----3)-O-beta-D-galactopyranosyl-(1----4)-2- acetamido-2-deoxy-D-glucopyranose (N-acetyl-3'-O-alpha-L-fucopyranosyllactosamine).

Methyl 2-O-benzyl-beta-D-galactopyranoside (6) was obtained in five, good yielding steps from methyl beta-D-galactopyranoside (1). Treatment of 1 with tert-butylchlorodiphenylsilane in N,N-dimethylformamide in the presence of imidazole afforded a 6-(tert-butyldiphenylsilyl) ether, which was converted into its 3,4-O-isopropylidene derivative (3). Benzylation of 3 with benzyl bromide-silver oxide in N,N-dimethylformamide, and subsequent cleavage of its acetal and ether groups then afforded 6. On similar benzylation, followed by the same sequence of deprotection, benzyl 2-acetamido-3,6-di-O-benzyl-4-O-[6-O-(tert-butyldiphenylsilyl)-3,4 -O- isopropylidene-beta-D-galactopyranosyl]-2-deoxy-alpha-D-glucopyranoside gave the 2-O-benzyl derivative (10). Compound 10 was converted into its 4,6-O-benzylidene acetal (11). Glycosylation (catalyzed by halide-ion) of 11 with 2,3,4-tri-O-benzyl-alpha-L-fucopyranosyl bromide afforded the fully protected trisaccharide derivative (13). Cleavage of the benzylidene and then the benzyl groups of 13 furnished the title trisaccharide (16). The structure of 16 was established by 13C-n.m.r. spectroscopy.

Benzyl Compounds↗

PubMed1991

Comparative study of chromatography on thin layers impregnated with organic stationary phases. Chromatographic separation of nitrophenols.

The chromatographic behaviour of nitrophenols on thin layers of silica gel and cellulose was compared, both without impregnation and impregnated with non-aqueous polar stationary phases (formamide, dimethylformamide) and less polar stationary phases (liquid paraffin, octan-1-ol, 1-bromonaphthalene). Cellulose is preferred when using formamide or dimethylformamide if a pure partition process is required. For each particular analyte a certain amount of the stationary phase is always required to suppress the adsorption activity of silica gel. Separation by reversed-phase thin-layer chromatography is strongly affected by the type of stationary phase (the possibility of forming charge-transfer complexes with 1-bromonaphthalene) and its support (the acidic properties of silica gel and its adsorption activity), the mobile phase (content of organic modifier, pH, presence of salts) and the properties of the solutes (polarity, ionizability).

Cellulose↗

PubMed1991

Exposure limits for occupational and environmental chemical pollutants in various media.

Exposure limits for occupational and environmental chemical contaminants are based on animal experimentation and observation in humans. Usually, the final recommendations are "predictions" which can hardly guarantee the absolute safety for all. Late effects were discovered to lately in the past. The impact of the biotransformation of pollutants on their biological activity is demonstrated with trichloroethylene, styrene and N,N-dimethylformamide, which are suspected of having carcinogenic potential. In addition, trichloroethylene and N,N-dimethylformamide cause intolerance of alcohol with hyperacetaldehydemia; acetaldehyde is claimed to be carcinogenic as well. The biotransformation of these three widely used substances differs among various species. Different fate of chemicals in human and animal organisms results in the necessity to consider kinetic and metabolic studies in setting limits; in microorganisms also metabolites supposed to be formed in humans should be tested. Limits for some pollutants in various media are given.

Animals↗

PubMed1997

Use of metal complexation in non-aqueous capillary electrophoresis systems for the separation and improved detection of tetracyclines.

Metal complexation in non-aqueous capillary electrophoresis systems was evaluated for the separation and improved detection of tetracycline antibiotics using laser-induced fluorescence detection. It was found that three factors were important for the choice of complexing agent: (i) it should be soluble in the organic solvent used for the separation, (ii) it should have a sufficient fast complexing rate so as not to invalidate the electrophoretic separation and, (iii) it should give a large increase in the fluorescence intensity. Mg2+ ions were found to be the most suitable ions for the separation of the tetracyclines as the acetate salt of magnesium is very soluble in organic solvents and only a relatively low current was generated during electrophoresis making it possible to use high concentrations of the complexing metal ion. Metal complexation strongly intensified the fluorescence of tetracyclines and all organic solvents investigated further intensified the fluorescence, e.g. dimethylformamide improved the fluorescence of the oxytetracycline metal complex by a factor of 34 compared to water. However, magnesium acetate was not sufficiently soluble in dimethylformamide and therefore N-methylformamide, improving the fluorescence intensity by only a factor of 9, was used. It was demonstrated that the method can be used for the detection of tetracyclines at the ppb level in milk and plasma.

Animals↗

PubMed1996

The use of substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group in the localization of protease activities in situ.

A method for the localization of activities of proteases using substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group is described. 0.1 ml of 5-20 mMol solution of the respective substrate (Gly-Pro-AFC, Ala-Pro-AFC, Z-Ala-Arg-Arg-AFC, Z-Gly-Arg-Arg-AFC, Z-Gly-Gly-Arg-AFC, D-Val-Leu-Lys-AFC) in dimethylsulfoxide or dimethylformamide was added to 0.9 ml of 0.1 M Tris-HCl buffer, pH 7.4-7.8 or 0.1 M cacodylate buffer, pH 5-5.5. In the case of Z-Ala-Arg-Arg-AFC (cathepsin B substrate) 15 mM EDTA and 12 mM dithiothreitol were added. 7 mM amiloride or 2 mg/1 ml aprotinin were used as inhibitors with Z-Gly-Gly-Arg-AFC (urokinase substrate) and with D-Val-Leu-Lys-AFC (plasmin substrate). Substrate solutions were mixed with an equal amount of 2% agar solution in distilled water or in the respective buffer the pH of which was adjusted according to the pH optimum of the enzyme to be demonstrated. The agar solution was kept in a water bath at a temperature of 50-60 degrees C. After careful mixing, the substrate solution in agar was poured into a cylindrical vessel closed with a semipermeable membrane (Nephrophan) on which unfixed cryostat sections were mounted. 1-5 mM AFC solution in dimethylsulfoxide or dimethylformamide instead of the substrate was used as the control. Quenched samples of rat kidney and jejunum, biopsies of human jejunal mucosa, and of colorectal and uterine tumors were employed for the preparation of sections. After gelification of the medium in a refrigerator the vessels with sections were incubated in the dark at 37 degrees C for 0.5-several h. The reaction was controlled in a fluorescence microscope with an epiillumination adjusted to the FITC fluorescence and documented. A yellowish green fluorescence depicts sites where AFC was set free (sites with enzyme activity). When the reaction reached the required intensity the membranes were cut off, transferred to glass slides, mounted in glycerol, observed and photographed immediately (due to the solubility of AFC in glycerol). An acceptable cellular localization was achieved. The method with AFC substrates can be recommended for comparative biochemical and histochemical studies of proteases using the same substrate and for cases in which no other reliable procedure for the localization of the respective enzyme activity is available (e.g. urokinase, plasmin).

Animals↗

PubMed2000

Low-temperature crystal structures of tetrakis-mu-3,5-diisopropylsalicylatobis-dimethylformamidodico pper(II) and tetrakis-mu-3,5-diisopropylsalicylatobis-diethyletheratodicopp er(II) and their role in modulating polymorphonuclear leukocyte activity in overcoming seizures.

Two binuclear copper(II) complexes of 3,5-diisopropylsalicylic acid were characterized by single crystal X-ray diffraction methods and examined for anti-inflammatory activity using activated polymorphonuclear leukocytes and for anticonvulsant activities using electroshock and metrazol models of seizures. These complexes were crystallized from dimethylformamide (DMF) or diethylether. Tetrakis-mu-3,5-diisopropylsalicylatobis-dimethylformamidodicop per(II) [Cu(II)2(3,5-DIPS)4(DMF)2] I is in space group P 1; a = 10.393 (2), b = 11.258 (2), c = 12.734 (2) A, alpha = 96.64 (2), beta = 92.95 (2), gamma = 94.90 (2) degrees; V = 1471.7 (4) A3; Z = 1. Tetrakis-mu-3,5-diisopropylsalicylatobis-etheratodicopper(II ) [Cu(II)2(3,5-DIPS)4(ether)2] II is in space group P 1; a = 10.409 (3), b = 11.901 (4), c = 12.687 (6) A, alpha = 91.12 (5), beta = 90.84 (5), gamma = 100.90 (4) degrees; V = 1542 (1) A3; Z = 1. The structure of I was determined at 140 K from 4361 unique reflections (I > 2sigma(1)) and refined on F2 to R1 = 0.04 and wR2 = 0.09. The structure of II was determined at 180 K from 4605 unique reflections (I > 2sigma(I)) and refined on F2 to R1 = 0.05 and wR2 = 0.13. Each compound is a crystallographically centrosymmetric binuclear complex with Cu atoms bridged by four 3,5-diisopropylsalicylate ligands related by a symmetry center [Cu-Cu(i): 2.6139 (9) A in I and 2.613 (1) in II]. The four nearest O atoms around each Cu atom form a nearly rectangular planar arrangement with the square pyramidal coordination completed by the dimethylformamide (or diethylether) oxygen atom occupying an apical position, at a distance of 2.129 (2) A in I and 2.230 (3) A in II. Each Cu atom is displaced towards the DMF (or diethylether) ligand, by 0.189 A in I and 0.184 A in II, from the plane of the four O atoms. The crystal structures of I and II are essentially similar to each other, except for the DMF or diethylether accommodation. Many disorder phenomena were found in the crystal structure of I. Copper(II)2(3,5-DIPS)4(DMF)2 inhibited polymorphonuclear leukocyte (PMNL) oxidative metabolism in vitro. This effect was concentration related and significant for concentrations higher than 10 microg or 0.68 nmol/ml. Copper(II)2(3,5-DIPS)4(DMF)2 was more active than the parent ligand, 3,5-DIPS, as has been demonstrated with copper complexes of other non-steroidal anti-inflammatory drugs. The DMF and diethylether ternary complexes of Cu(II)2(3,5-DIPS)4 were found to have anticonvulsant activity in the maximal electroshock model of grand mal epilepsy in doses ranging from 26 to 258 micromol/kg of body mass following intraperitoneal, subcutaneous, or oral treatment. The DMF ternary complex was also found to be effective in the subcutaneous injection of metrazol model of petit mal epilepsy. We conclude that both ternary copper complexes are lipophilic and bioavailable, capable of facilitating the inflammatory response to brain injury and causing the subsidence of this response in bringing about remission of these disease states.

Animals↗