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1

The comparative study of influence of lactic and glycolic acids copolymers type on properties of daunorubicin loaded nanoparticles and drug release

Nikolskaya E., Sokol M., Faustova M., Zhunina O., Mollaev M., Yabbarov N., Tereshchenko O., Popov R., Severin E.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 1

65--77

EN

The aim of this study was to compare the physico-chemical and biological properties of polymeric nanoparticles obtained from poly(DL-lactide-co-glycolide) (PLGA) with different ratios of monomers loaded with daunorubicin (DNR). Methods: DNR-loaded nanoparticles (NPs) were prepared with use of modified simultaneous double-emulsion solvent evaporation/diffusion technique. NPs were characterized using dynamic light scattering, atomic force microscopy, transmission electron microscopy, scanning electron microscopy, and differential scanning calorimetry and Fourier transform infrared spectroscopy. Results: NPs with DNR were differing in size and zeta potential, depending on the type of polymer. The data obtained show that total content of DNR correlates with the values of the binding constant of DNR with polymers. The release of DNR from NPs proceeds predominantly for polymers with lower binding constants. The in vitro study of NPs on the MCF-7 cells showed similar activity of particles and substances while for the anthracycline-resistant MCF-7Adr cells the cytotoxicity of the nanoparticles was 3 to 7 times higher depending on the type of copolymer. Conclusions: PLGA DNR-loaded nanoparticles can be used to overcome multidrug resistance (MDR) as well as for reducing the frequency of DNR reception due to the prolonged effect, which allows maintaining the concentration of the drug at the required level. The usefulness of binding constant calculations for obtaining nanoparticles with the maximum drug loading was proven. The rate of drug administration and the frequency of administration can be calculated based on the DNR release profiles and release parameters that depend on polymer type.

2

Dissociation Constants of Some Quinoline Derivatives in Mixed Solvent mixture

Baluja S.

International Letters of Chemistry, Physics and Astronomy

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2015

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Vol. 48

32--36

EN

The dissociation constants of some derivatives of quinoline have been determined by Calvin Bjerrum pH titration method in DMF–water (60:40 v/v) mixture at 308.15 K. It is observed that dissociation constant depends on the substituents present in the compound.

3

Investigations of selected properties of pharmacologically active compounds by chromatographic and potentiometric methods on the chrysin example

Pusz J., Zapała W., Papciak B.

Polish Journal of Chemical Technology

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2008

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Vol. 10, nr 1

41-44

EN

The RP-TLC method was used to determine the dissociation constant of chrysin (5,7-dihydroxyflavone) in methanol-aqueous (1:1 v/v) solutions. In this method the pK value was quantified on the basis of retention data and a retention model. The accuracy of determining the model parameters was analysed using the following statistical criteria: the sum of the squared differences between the experimental and theoretical data, approximation of standard deviation, and the Fisher test. Besides, in this work the potentiometric method was used. Investigations were carried out at ionic strength I=0.1 at T= 298 K. The dissociation constant were determined using the Rossotti method as well as the numerical method based on the procedures of non-linear curve fitting using Microsoft Excel Solver and the user-defined function. It has been found that the differences in the evaluated pK values were relatively small and did not exceed 1.2%.

4

Study of poly(itaconic acid) in aqueous solutions

Połowiński S.

Polimery

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2006

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T. 51, nr 4

270-275

EN

Poly(itaconic acid) (PIA) have been synthesized by hydrolysis of poly(itaconic anhydride) and by polymerization of itaconic acid initiated by redox system. Conductometric, potentiometric and spectrophotometric titration of aqueous solutions of PIA have been carried out. The results are discussed in terms of a conformational transition. Apparent dissociation constant and conductance of PIA solutions have been investigated as functions of concentration.

PL

Przeprowadzono syntezy poli(kwasu itakonowego) poprzez hydrolizę poli(bezwodnika kwasu itakonowego) oraz na drodze polimeryzacji inicjowanej układem redoks. Wykonano miareczkowania konduktometryczne, potencjometryczne i spektrofotometryczne roztworów wodnych otrzymanych polikwasów. Stwierdzono, że badane polikwasy zawierają około 66 % dostępnych grup karboksylowych (rys. 1 i 7). Wysunięto hipotezę o przemianie konformacyjnej, która powoduje niedostępność pozostałych grup karboksylowych. Wyznaczono zmiany potencjału termodynamicznego związanego z taką przemianą DG = 5,4-5,9 kJ/eq (tabela 1, rys. 4 i 5). Badano przewodnictwo elektryczne roztworów polikwasów (rys. 8 i 9) i zaobserwowano liniową zależność odwrotności przewodnictwa równoważnikowego od pierwiastka kwadratowego ze stężenia PIA.

5

Ability of 2,4D and 2,4DP Herbicides to Combine with Metal Ions of biological Interest (Part 2): Zine(II) Complexes

Zwolińska A., Ptaszyński B.

Polish Journal of Chemistry

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2005

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Vol. 79 / nr 4

645-654

EN

Zinc(II) complexes with the commercial auxin herbicides 2,4-dichlorophenoxyacetic acid (2,4D; C8H6O3Cl2) and 2-(2,4-dichlorophenoxy)-propionic acid (2,4DP; C9H8O3Cl2) were prepared and characterized. The formulae of the solid complexes Zn2(C8H5O3Cl2)3_5H2O (Zn-2,4D) and Zn(C9H7O3Cl2)2_1.5H2O (Zn-2,4DP) were established on the basis of the results of elemental analysis and Zn(II) determination.Water solubility of synthesized complexes at room temperature was examined. X-ray powder analysis was carried out. The discussion of IR spectra and conductivity data is presented. Thermal decomposition of these complexes in air was studied by TG, DTG, DTA and TG/MS methods with simultaneous analysis of the solid and gaseous products. The formation of complexes Zn-herbicide in the water solution by potentiometric pH titration was also investigated. The dissociation constants (pK) of 2,4D and 2,4DP were determined at 25°C and I = 0.1 (KNO3).