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At least 19 recordsLinked to original sources

The determination of oxalic acid, oxamic acid, and oxamide in a drug substance by ion-exclusion chromatography.

Oxalic acid, oxamic acid and oxamide are potential impurities in some active pharmaceutical ingredients (API). The retention and separation of oxalic and oxamic acids are particularly challenging using conventional reversed-phase HPLC due to their high polarity. An ion-exclusion chromatography (IEC) method has been shown to provide good separation and sensitivity for the three oxalate-related impurities in a hydrophobic API matrix. The method uses a Dionex IonPac ICE-ASI column with 95/5 (v/v) 0.1% sulfuric acid/acetonitrile as the mobile phase and UV detection at 205 nm. Development and validation of this method are described.

Chromatography, Gel↗

(2-Carboxy-1,4-dihydro-4-oxoquinolyl)oxamic acids and (2-carboxy-1,4-dihydro-4-oxobenzo[h]quinolyl)oxamic acids as antiallergy agents.

A group of (2-carboxy-1,4-dihydro-4-oxoquinolyl)oxamic acids (5) containing the oxamic acid group in the 5,6, or 7 positions were synthesized and investigated for antiasthma activity as indicated by the passive cutaneous anaphylaxis (PCA) reaction in rats. Also synthesized and investigated were two (2-carbosy-1,4-dihydro-4-oxobenzo[h]-quinolyl)oxamic acids (9 and 10). Several of the compounds synthesized (viz. 5e, 5f, and 10) showed activity in the PCA test approximately 25 times that shown by disodium cromoglycate (1), as measured by the ID50 doses.

Animals↗

The anaerobic metabolism of metronidazole forms N-(2-hydroxyethyl)-oxamic acid.

N-(2-hydroxyethyl)-oxamic acid is formed when metronidazole is reduced either chemically or by the action of the intestinal bacteria. When metronidazole, labeled with carbon-14 in the hydroxyethyl side chain, is administered by gavage to rats in doses of 200 mg/kg, an average of 1.4% of the administered radioactivity is recovered in the urine in the form of N-(2-hydroxyethyl)-oxamic acid. The presence of conjugated N-(2-hydroxyethyl)-oxamic acid in some samples was suggested by the detection of small additional amounts of the free acid after treatment of the urine with beta-glucuronidase. The metabolite is not found in the feces. In contrast N-(2-hydroxyethyl)-oxamic acid is not found in the urine or feces of germfree rats which receive metronidazole. Thus, the finding of N-(2-hydroxyethyl)-oxamic acid in the urine of rats which receive metronidazole appears to depend on the activity of the bacterial flora.

Anaerobiosis↗

Selective isolation of Vibrio cholerae neuraminidase using an immobilized 4-(nitrophenyl)oxamic acid.

N-(4-Nitrophenyl)oxamic acid[1] (1) was coupled with Sepharose 4B containing 1,6-diaminohexane as spacer group. This material was used as a specific adsorbent in the purification of Vibrio cholerae neuraminidase. The enzyme was completely retarded and separated from the bulk of the protein when washed with 50mM sodium acetate buffer, pH 5.0. A stepwise increase of sodium chloride concentration from 1.0 to 2.0M was found to be necessary for a sharp elution of neuraminidase activity. The purification was tenfold, and a recovery of more than 90% was obtained. Neuraminidase is only weakly retarded on a column of 1,6-diaminohexane coupled with Sepharose 4B and is not adsorbed by Sepharose 4B.

Chromatography, Affinity↗

N-(4-Isoxazolylthiazol-2-yl)oxamic acid derivatives as potent orally active antianaphylactic agents.

A series of N-(4-isoxazolylthiazol-2-yl)oxamic acid derivatives was synthesized and tested on the passive cutaneous anaphylaxis (PCA) model in rats to verify its potential antianaphylactic activity. These compounds were prepared by reaction of an appropriate bromoacetylisoxazole with thiourea to give the corresponding aminothiazole and subsequent condensation with an oxalic acid monoester chloride to yield, following the usual process, the oxamic acid derivatives. Most of the new compounds exhibited, by intraperitoneal route in rats, a very potent antianaphylactic activity on PCA response, higher than that of the reference compound disodium cromoglycate (DSCG). The new derivatives, in contrast with DSCG, were effective on PCA even by oral route. The most interesting derivative of the new series was N-[4-(3-methyl-5-isoxazolyl)-2-thiazolyl]oxamic acid 2-ethoxyethyl ester (49), which was also active and more potent than DSCG in experimental models involving either IgE- or IgG-mediated anaphylactic responses at bronchopulmonary level.

Administration, Oral↗

Regulation of gene expression in cardiomyocytes by thyroid hormone and thyroid hormone analogs 3,5-diiodothyropropionic acid and CGS 23425 [N-[3,5-dimethyl-4-(4'-hydroxy-3'-isopropylphenoxy)-phenyl]-oxamic acid].

The heart is an important target of thyroid hormone actions. Only a limited number of cardiac target genes have been identified, and little is known about their regulation by T(3) (3,3',5-triiodothyronine) and thyroid hormone analogs. We used an oligonucleotide microarray to identify novel cardiac genes regulated by T(3) and two thyroid hormone analogs, 3,5-diidodothyropropionic acid (DITPA) and CGS 23425 [N-[3,5-dimethyl-4-(4'-hydroxy-3'-isopropylphenoxy)-phenyl]-oxamic acid]. DITPA binds with lower affinity than T(3) to thyroid hormone receptor alpha1 and beta1 isoforms, whereas CGS 23425 binds selectively to beta1. Fluorescent-labeled cDNA was prepared from cultured heart cells maintained in medium stripped of thyroid hormone ("hypothyroid" control) or treated with T(3), DITPA, and CGS 23425 at concentrations 5 times their respective K(d) values for 48 h. The arrays were scanned and analyzed using an analysis of variance program. Sixty-four genes were identified that were >1.5 times up- or down-regulated by one of the treatments with P < 0.05. The genes regulated by T(3) and DITPA were nearly identical. Thirteen genes were differentially regulated by CGS 23425. Genes encoding contractile proteins, Ca(2+)-ATPase of sarcoplasmic reticulum and several proteins of mitochondrial oxidative phosphorylation, were up-regulated by T(3) and DITPA but not by CGS 23425. These results indicate that some, but not all, of the actions of thyroid hormone analogs can be explained by differences in gene activation.

Animals↗

N-(4-substituted-thiazolyl)oxamic acid derivatives, a new series of potent, orally active antiallergy agents.

A series of N-(4-substituted-thiazolyl)oxamic acid derivatives were synthesized and tested for antiallergy activity in the rat PCA model. These compounds were conveniently prepared by treatment of the appropriate acetophenone with thiourea and iodine or by reaction of the chloroacetylbenzene with thiourea to give the corresponding aminothiazoles; subsequent condensation with ethyloxalyl chloride gave the thiazolyloxamates. Many of the analogues showed a 50% inhibition at less than 2 mg/kg po or less than 0.4 mg/kg iv and were significantly more potent than disodium cromoglycate, which in the rat PCA model is orally inactive and gives a 50% inhibition at 1.2 mg/kg iv. Hydrolysis of the oxamates generally resulted in enhanced activities, while substitution of the phenyl ring with a variety of substituents (e.g., 4-F, 4-OEt, and 4-NHCOCH3) did not significantly enhance the activity of the unsubstituted phenyl derivative. One of the ethanolamine salts, N-[4-(1,4-benzodioxan-6-yl)-2-thiazolyl]oxamic acid ethanolamine salt (61, PRH-836-EA), has been selected for further pharmacological evaluation.

Animals↗

Synthesis and structure-activity relationships of oxamic acid and acetic acid derivatives related to L-thyronine.

Aryloxamic acids 7 and 23, (arylamino)acetic acids 29, arylpropionic acids 33, arylthioacetic acids 37, and (aryloxy)acetic acid 41 related to L-triiodothyronine (L-T3) were prepared and tested in vitro for binding to the rat liver nuclear L-T3 receptor and the rat membrane L-T3 receptor. The structure-activity relationships for these compounds are described, with 7f, 23a, 29c, 33a, 37b, and 41 showing excellent potency (IC50's of 0.19, 0.16, 1.1, 0.11, 3.5, and 0.10 nM, respectively) to the nuclear receptor and significantly lower binding affinity to the membrane receptor (IC50's > 5 microM). Some of these compounds, especially in the oxamic acid series 7 and 23, showed an unprecedented potency for methyl-substituted derivatives such as 7f and 23a. Compounds 7f and 23a showed good lipid lowering effects in rats with ED50's of 20 and 5 micrograms/kg po, respectively, and a lack of cardiac side effects in rats at doses as high as 10 and 25 mg/kg po, respectively.

Acetates↗

Magnetic Properties of a Series of Trinuclear Complexes (CuL)(2)Mn.xB (L Representing the Deprotonated Form of N-(4-Methyl-6-oxo-3-azahept-4-enyl)oxamic Acid and B Representing Respectively H(2)O (x = 5, 4.5, 3, 1), (CH(3))(2)SO (x = 2), and C(5)H(5)N (x = 4)). Crystal and Molecular Structure of (CuL)(2)Mn.2(CH(3))(2)SO.

A series of (Cu, Mn, Cu) complexes have been prepared and characterized. They may be described by the overall formula (CuL)(2)Mn.xB where L stands for the deprotonated form of N-(4-methyl-6-oxo-3-azahept-4-enyl)oxamic acid and B for respectively H(2)O (with x = 5, 4.5, 3, 1), (CH(3))(2)SO (with x = 2), and C(5)H(5)N (with x = 4). The crystal and molecular structures of (CuL)(2)Mn.2(CH(3))(2)SO have been solved. The crystals are monoclinic, space group P2(1)/n with cell constants a = 8.362(2) Å, b = 14.426(3) Å, c = 24.442(6) Å, and Z = 4. In each (Cu, Mn, Cu) molecular unit the central Mn(II) ion is bridged to two copper(II) ions through two oxamato groups. Short intermolecular Cu.Cu distances lead to the formation of a chain-like packing pattern running parallel to the c-axis. Magnetic susceptibility measurements have been performed for the six complexes. Five complexes display the same behavior which corresponds to the occurrence of antiferromagnetic Cu-Mn interactions within isolated trinuclear units. The J values are between -29.4(2) and -33.8(5) cm(-)(1). Surprisingly the field and temperature dependence of the magnetization for (CuL)(2)Mn.4.5H(2)O confirms that a magnetic phase transition occurs at low temperature and that, below T(c) = 37 K, the complex displays weak ferromagnetism.

Journal Article↗