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G Sosnovsky

Publications and source records attributed to G Sosnovsky.

35 records · Page 2Linked to original sources
PubMed1986

In the search for new anticancer drugs. 17. Linear and cyclic polyether analogues of N,N:N',N':N'',N''-tri-1,2-ethanediylphosphoric triamide and N,N:N',N':N'',N''-tri-1,2-ethanediylphosphorothioic triamide.

Linear and cyclic polyether derivatives of N,N:N',N':N'',N''-tri-1, 2-ethanediylphosphoric triamide (TEPA) and N,N:N',N':N'',N''-tri-1,2-ethanediylphosphorothioic triamide (thio-TEPA) are synthesized and evaluated for their antineoplastic activity against the murine lymphocytic leukemia P388. All compounds, except for 7d, were active ranging from 42% to 287% increase in life span (% ILS). All CD2F1 male mice treated with the most active compound (7a) at 90 mg/kg per day for 9 days were alive after 30 days, whereas all mice treated with the clinical drug thio-TEPA were dead. The % ILS for compound 7a on day 60 was 525. A correlation is presented between the structural features of compounds and their lipophilicities and antineoplastic activities.

Animals↗
PubMed1986

In the search for new anticancer drugs. 19. A predictive design of N,N:N',N':N'',N''-tri-1,2-ethanediylphosphorothioic triamide (TEPA) analogues.

The nitroxyl-labeled analogues of N,N:N',N':N",N"-tri-1,2-ethanediylphosphoric triamide (TEPA), N,N:N',N'-bis(1,2-ethanediyl)-N"-[[(2,2,6,6-tetramethyl-1-oxypiperidi n-4- yl)amino]carbonyl]phosphoric triamide (5a) and N,N:N',N'-bis(1,2-ethanediyl)-N"-[[(2,2,5,5-tetramethyl-1-oxypyrrolid in-3- yl)amino]carbonyl]phosphoric triamide (11a), possess therapeutic indexes that are 8-12 times higher than those of thio-TEPA (1) and TEPA (2). The introduction of methyl groups into the aziridine ring, or the replacement of the nitroxyl moiety with hydroxylamine or amine derivatives, or with an adamantane moiety, results in compounds of lesser activity. An attempt is made to rationalize these results using a lipophilicity scale. A predictive design pattern is established.

Animals↗
PubMed1986

Diradical nitroxyl spin label contrast agents for magnetic resonance imaging. A comparison of relaxation effectiveness.

The proton relaxation enhancement characteristics of seven potential MRI contrast agents containing two nitroxyl spin labels per molecule (diradicals) were compared with eight similar agents with only one spin label per molecule (monoradicals). Diradical nitroxyls were evaluated to test the hypothesis that multiple paramagnetic centers in one molecule will result in stronger proton relaxation enhancement characteristics, allowing effective contrast enhancement at lower molar concentrations and thus a reduced osmotic load and greater safety. The acute toxicity of these agents is believed to be largely related to osmotic load. Five of seven diradical nitroxyls tested had spin-lattice relaxivities that were substantially greater than all eight of the monoradicals tested. The spin-spin relaxation properties of these agents and other pertinent characteristics are favorable for contrast enhancement. The results indicate that diradical nitroxyl spin labels may be used advantageously for the design of safer, more effective MRI contrast agents.

Chemical Phenomena↗
PubMed1985

In the search for new anticancer drugs. X. N,N; N',N'-bis(1,2-ethanediyl)-N''-(1-oxyl-2,2,6,6-tetramethyl- 4-piperidinylaminocarbonyl) phosphoric triamide--a new potential anticancer drug of high activity and low toxicity.

A new nitroxyl labeled TEPA derivative 5 containing the urea bridge between the phosphorus and the nitroxyl moiety, and the congeners containing the NOH and NH groups instead of the nitroxyl function were synthesized, and tested in vivo on CD2F1 mice for anticancer activity against P388 and L1210. The nitroxyl compound is more active than the reduced forms. The nitroxyl compound 5 elicits 170% ILS at 90 mg/kg after 30 days and 439% ILSmax after 60 days against P388, and has a higher therapeutic ratio (26.4) than the clinically used Thio-TEPA (2.75). The LD50 of 5 is 270 mg/kg, while that of Thio-TEPA is 18 mg/kg. Consequently, the nitroxyl compound 5 is a promising new anticancer drug.

Animals↗
PubMed1985

In the search for new anticancer drugs XII. Synthesis and biological evaluation of spin labeled nitrosoureas.

The spin labeled nitrosourea 1-(2-chloroethyl)-3-(1-oxyl-2,2,6,6- tetramethyl-piperidinyl)-1-nitrosourea (SLCNU, 4) and its analogues 5-7 were synthesized either by a regio-selective method or by a conventional route via the nitrosation of the spin labeled intermediates (11a-e). Nitrosation of the ureas 11a-e with dinitrogen tetraoxide resulted in better yields than those obtained with sodium nitrite. The nitrosoureas 4-8 were tested for their anticancer activity against the lymphocytic leukemia P388 in mice. Thus, either at the equal molar dose or at the dose of equal toxicity level, the SLCNU (4) was found to be more active than the clinically used CCNU (1). Unlike CCNU (1) whose LD50 is 56 mg/kg, the SLCNU (4) possesses a low toxicity (LD50 123 mg/kg). Therefore, SLCNU (4) is a promising new entry into the nitrosourea class of anticancer drugs.

Animals↗
PubMed1985

On the search for new anticancer drugs 14: the plasma pharmacokinetics and tissue distribution of spin-labeled thio-TEPA (SL-O-TT).

We defined the plasma and tissue concentrations and pharmacokinetics of SL-O-TT, a spin-labeled analog of thio-TEPA, in 35-44-g male Swiss Webster mice that had received spin-labeled thio-TEPA at a dosage of 10 mg/kg. Concentrations of spin-labeled thio-TEPA in ethyl acetate extracts of tissue and plasma were determined by gas-liquid chromatography and electron spin resonance spectroscopy. Plasma concentrations of spin-labeled thio-TEPA declined in a biexponential fashion that was well described by the equation: Ct = 21.5e-0.276t + 2.30e-0.026t indicating a half-life alpha of 2.5 min and a half-life beta of 26.6 min. After 2 h there was still spin-labeled thio-TE-PA in plasma, but not in tissues. In tissues, no spin-labeled thio-TEPA was detected with gas-liquid chromatography 15 min after injection, but with electron-spin resonance label was found in lung and skeletal muscle. The main metabolite of spin-labeled thio-TEPA is spin-labeled TEPA, where oxidative desulfurization is invoked as the main metabolic mechanism. Reduction of the spin label to the hydroxylamine was also observed with time.

Animals↗
PubMed1985

In the search for new anticancer drugs. XV. Various aliphatic and aromatic hydrazones containing the N,N;N',N'-bis(1,2-ethanediyl)phosphoric diamide moiety.

The scope of the structure-anticancer activity relationship among various aliphatic and aromatic hydrazones containing the N,N,N',N'-bis(1,2-ethanediyl)-phosphoric diamide moiety was studied. A total of 19 compounds were tested in vivo, using murine lymphocytic leukemia P388. At optimum dose all these compounds were active. The highest activity was exhibited by the N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- hydrazin-1-yl]phosphoric triamide, N,N;N',N'-bis(1,2-ethanediyl)-N2-(p-chlorobenzylidene)-N1- methylhydrazin-1-yl]phosphoric triamide and N,N;N',N'-bis(1,2-ethanediyl)-[N2-(p-chlorobenzylidene)-N1- phenylhydrazin-1-yl]phosphoric triamide as is evidenced by the percent T/C of 212, 194 and 192, respectively. An attempt was made to correlate the anticancer activities with the corresponding lipophilicities. On the basis of the activity-lipophilicity results, it is concluded that, in general, the activity scale follows the lipophilicity scale in the reverse order, i.e. the more active compounds possess lower lipophilicity than the less active compounds.

Animals↗
PubMed1985

Magnetic field dependence of spin-lattice relaxation enhancement using piperidinyl nitroxyl spin-labels.

We examined the magnetic resonance properties of 12 paramagnetic piperidinyl nitroxyls in water and plasma solutions. Paramagnetic contributions to proton relaxation times were measured using 10.7 and 100 MHz spectrometers. Proton relaxation enhancement from nitroxyls increased with ascending molecular weight, in plasma solutions versus equimolar aqueous solutions, and with measurements at 10.7 MHz compared to 100 MHz. Relaxation rates were observed to approximately double at 10.7 MHz compared to 100 MHz and from water to plasma solutions. The data indicate that proton spin-lattice relaxation enhancement is magnetic field-dependent, and increases using nitroxyls of large molecular weight and with chemical substitutents that increase the microviscosity of solvent water molecules. The development of nitroxyls for diagnostic MRI will be aided by understanding these in vitro physical characteristics and trends.

Contrast Media↗
PubMed1985

Factors affecting nitroxide reduction in ascorbate solution and tissue homogenates.

Because of their paramagnetic properties, nitroxides are potentially useful as contrast agents in magnetic resonance imaging (MRI). They are reduced in vivo to their corresponding hydroxylamines which are nonparamagnetic and have no contrast enhancing property. Nitroxides with high resistance to reduction would be advantageous as pharmaceutical contrast enhancing agents. We show that in the presence of ascorbic acid and in tissue homogenates, the reduction is faster for piperidine than for pyrrolidine nitroxides and for positively-charged than for negatively-charged derivatives. The data also suggest that nitroxide reduction in tissue homogenates is mainly due to sulfhydryl groups on proteins and that endogenous ascorbic acid plays a relatively minor role.

Animals↗
PubMed1985

In the search for new anticancer drugs XI. Anticancer activity of nitroxyl labeled phosphoric N,N;N',N';N",N"-tris[1,2-ethanediyl]triamide(TEPA) and phosphorothioic N,N;N',N';N",N"-tris[1,2-ethanediyl]triamide(thio-TEPA) derivatives.

In order to further evaluate the effect of the nitroxyl moiety on the anticancer activity of nitroxyl labeled analogues of phosphoric N,N;N',N';N",N"-tris[1,2-ethanediyl]triamide (TEPA) and phosphorothioic N,N;N',N';N",N"-tris[1,2-ethanediyl]triamide (thio-TEPA), the activity of these compounds was compared in vivo, using murine lymphoid leukemia L1210, with the reduced forms of the drugs, i.e. the hydroxylamines and amine congeners. At optimum dose, all compounds were active. However, the nitroxyl containing compounds were more active than the corresponding reduced forms. An admixture of 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl had no effect on the activity of thio-TEPA. Consequently, the nitroxyl moiety must be an integral part of the anticancer drug's structure in order to influence that drug's performance.

Animals↗
PubMed1985

In the search for new anticancer drugs. 13. Phosphonic and phosphinic analogues of ornithine.

Phosphonic (4a,b) and phosphinic (5a-d) analogues of ornithine were synthesized and evaluated for their inhibitory activity against ornithine decarboxylase and against the lymphocytic leukemia P388. The title compounds possess a low degree of inhibition against rat liver ornithine decarboxylase as compared to alpha-(difluoromethyl)ornithine. Thus, compounds 4a and 5a inhibit by 40% the ornithine decarboxylase activity at a 5 mM concentration. The other derivatives are less potent. Compounds 4a, 4b, 5b, and 5d are inactive against P388 tumor in CD2F1 mice at doses of 50 and 150 mg/kg.

Animals↗
PubMed1984

In the search for new anticancer drugs. VII. Platinum complexes of diaziridines and azetidine.

Three new diaziridine platinum(II) complexes (4a)-(4c), and a new azetidine platinum(II) complex (3b) were synthesized and tested against the lymphocytic leukemia P388 in mice. (formula; see text) Moderate to good activity was found for all compounds as evidenced by a T/C value of 162 at a dose of 32 mg/kg for (3b), 190 at a dose of 32 mg/kg for (4a), 139 at a dose of 4 mg/kg for (4b), and 142 at a dose of 20 mg/kg for (4c).

Animals↗
PubMed1984

In the search for new anticancer drugs. 9. Synthesis and anticancer activity of spin-labeled analogues of N,N:N',N':N",N"-Tri-1,2-ethanediylphosphoric triamide and N,N:N',N':N",N"-tri-1,2-ethanediylphosphorothioic triamide.

A number of N,N:N',N':N",N"-tri-1,2- ethanediylphosphoric triamide (TEPA) and N,N:N',N':N",N"-tri-1,2- ethanediylphosphorothioic triamide (thio-TEPA) derivatives containing either two aziridine moieties (1a) or two (2-chloroethyl)amino functions (1b) and either a 2,2,6,6-tetramethylpiperidine, 1-oxy-2,2,6,6-tetramethylpiperidine or 1-hydroxy-2,2,6,6-tetramethylpiperidine component were synthesized and tested against lymphocytic leukemia P388 in mice. In a structure-activity comparison it was found that at optimum dose all compounds containing the nitroxyl radical were more active than the corresponding hydroxylamine derivatives. The open-chain compounds (1b) were less active than the corresponding aziridine ring compounds (1a). The replacement of the X = bridge in 1a with the X = N(CH3) group resulted in lowering of the anticancer activity.

Animals↗
PubMedDate not supplied

In the search for new anticancer drugs, XXI. Spin labeled nitrosoureas.

The spin labeled nitrosoureas 7a-e and 12 were synthesized and evaluated in vivo for their anticancer activities against the murine lymphocytic leukemia P388. Compounds 7a-c, 7e and 12 possessed activities ranging from 31 to 542 percent increase in life span (%ILS), whereas compound 7d was marginal (%ILS = 21). All CD2F1 male mice treated with the most active compounds (7a and 12) at 35 mg/kg for 9 days were alive after 30 days, whereas all mice treated with the clinical drug CCNU (1c) succumbed. Compounds 7a-e and 12 were further evaluated for their antineoplastic activity against lymphoid leukemia L 1210. Compounds 7a and 12 exhibited, on day 60, a %ILS of 713 and 620, respectively. The lipophilicities of compounds 7a-e and 12 were determined using the EPR and UV methods. Compounds 7a and 12 which differ from CCNU and MeCCNU by the replacement of the cyclohexyl and methylcyclohexyl groups with six and five membered nitroxyl radical moieties were more hydrophilic than the clinical drugs.

Animals↗