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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

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%.

3

The modified method of spectro-pehametric determination of dissociation constants

Michałowski T., Wybraniec S., Ponikvar M.

Chemia Analityczna

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2008

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Vol. 53, No. 5

737-742

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

Potentiometric determination of pKa values of 1,4,5,8-tetrahydroxy-9-oxo-10-pentyl- 9,10-dihydro-acridine-2,3,6,7-tetracarboxylic acid (TPAT) extracted from Laurus Nobilis

Ibaoglu K., Sari H., Tuzen M., Mendil D., Soylak M.

Chemia Analityczna

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2004

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Vol. 49, No. 5

635-642

EN

The pKa values of 1,4,5,8-tetrahydroxy-9-oxo-10-pentyl-9,10-dihydro-acridine-2,3,6,7-tetracarboxylic acid (TPAT) extracted from Laurus nobilis were determined by Molspin potentiometric titration at 25°C in the presence of 0.1 mol dm-3 NaCl. The pKa values were calculated using SUPERQUAD computer program. Initially deprotonation occurs in carboxylic groups, then at the nitrogen atom of the alkyl group, and finally at the hydroxylic groups of TPAT. The following pKa values were computed: 2.65, 3.36, 4.08, 5.43, 6.84, 9.30, 10.42 and 10.53.

PL

Wyznaczono wartości pKa kwasu 1,4,5,8-tetrahydroksy-9-okso-1O-pentylo-9,10-dihydro-akrydyno-2,3,6,7-tetrakarboksylowego (TPAT) wyekstrahowanego z Laurus nobilis. Wyznaczanie pK przeprowadzono metodą potencjometry c zn ego miareczkowania Molspin'a wtemp. 25°C w obecności 0,1 mol dm(-3) NaCl. Wartości pK. obliczono przy użyciu programu komputerowego SUPERQUAD. W pierwszym rzędzie dysocjacji kwasowej ulegają grupy karboksylowe, później grupa =NH+ i na końcu grupy hydroksylowe. Dla poszczególnych stopni dysocjacji kwasowej wyliczono następujące wartości pK (a): 2,65; 3,36; 4,08; 5,43; 6,84:9,30; 10,42 and 10,53.