Solubility Study of Betulonic Acid in the Presence of Hydroxypropyl-γ-cyclodextrin by Capillary Electrophoresis

Попова, О В; Sursyakova, Viktoria V.; Burmakina, Galina V.; Maksimov, N. G.; Levdansky, Vladimir A.; Rubaylo, Anatoly I.

doi:10.17516/1998-2836-2016-9-2-171-176

Cited by 7 publications

(8 citation statements)

References 8 publications

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“…The coefficient allowing the correction for viscosity change for each BGE, υ, was calculated as follows: [5,15]:

υ = \frac{t^{'}}{t^{0}}

where t' and t 0 are the times for the DMSO peaks obtained at a voltage of 0 kV and a pressure of 100 mbar in BGEs with the HP‐β‐CD addition and without it, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…Betulin and its derivatives, pentacyclic lupane triterpenoids with anticancer and other types of biological activities, can be attributed to such drugs [3]. Recently, the complexation of a number of betulin derivatives (betulinic and betulonic acids, and sulphated betulin derivatives) with β‐CD, (2‐hydroxypropyl)‐β‐cyclodextrin (HP‐β‐CD), and (2‐hydroxypropyl)‐γ‐cyclodextrin (HP‐γ‐CD) has been studied [4–9], as well as the complexation of betulin 3,28‐diphthalate (DPhB) and betulin 3,28‐disuccinate (DScB) with HP‐γ‐CD [10].…”

Section: Introductionmentioning

confidence: 99%

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Determining binding constants for 1:1 and 1:2 inclusion complexes of ester betulin derivatives with (2‐hydroxypropyl)‐β‐cyclodextrin by affinity capillary electrophoresis

2020

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The complexation of ester betulin derivatives with (2‐hydroxypropyl)‐β‐cyclodextrin (HP‐β‐CD) was studied by mobility shift affinity CE. Electrophoretic mobility for triangular peaks was calculated using the parameter a1 of the Haarhoff–Van der Linde function instead of the peak top time. Dependences of the viscosity corrected electrophoretic mobility on HP‐β‐CD concentration were not described on the basis of only complexes with 1:1 stoichiometry due to the fact that these binding curves did not reach a plateau. However, the dependences were well described taking into account both 1:1 and 1:2 complexes. The presence of higher order equilibria was also revealed by x‐reciprocal plots. The values of apparent binding constant logarithm, obtained for the first time, for 1:1 and 1:2 HP‐β‐CD complexes of betulin 3,28‐diphthalate and betulin 3,28‐disuccinate with 95% confidence interval limits in brackets are the same within error and are equal to 4.85 (4.73–4.95), 8.56 (7.75–8.82), 4.92 (4.86–4.97), and 8.54 (8.23–8.72) at 25°C, respectively. These values for 1:1 and 1:2 HP‐β‐CD complexes of betulin 3,28‐disulfate at 25°C are 4.61 (4.57–4.64) and 7.11 (6.57–7.34), respectively. The binding constants for betulin 3,28‐disulfate agree with the previously obtained results from the separation in the thermostatted capillary segment.

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“…The coefficient allowing the correction for viscosity change for each BGE, υ, was calculated as follows: [5,15]:

υ = \frac{t^{'}}{t^{0}}

where t' and t 0 are the times for the DMSO peaks obtained at a voltage of 0 kV and a pressure of 100 mbar in BGEs with the HP‐β‐CD addition and without it, respectively.…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Determining binding constants for 1:1 and 1:2 inclusion complexes of ester betulin derivatives with (2‐hydroxypropyl)‐β‐cyclodextrin by affinity capillary electrophoresis

2020

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“…Pentacyclic lupane triterpenoids, such as betulin and its derivatives, exhibit antitumor and other types of biological activities [45]. Previously, the interaction of a number of betulin derivatives (betulinic and betulonic acids, and sulphated betulin derivatives) with β-CD, (2-hydroxypropyl)-β-cyclodextrin and (2-hydroxypropyl)-γ-cyclodextrin (HP-β-CD, HP-γ-CD) has been studied [7][8][9][46][47][48].…”

Section: Introductionmentioning

confidence: 99%

Determination of binding constants for strong complexation by affinity capillary electrophoresis: the example of complexes of ester betulin derivatives with (2-hydroxypropyl)-γ-cyclodextrin

2020

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Complexation plays an important role in many biological phenomena, the analysis of different samples, optimization of separation processes, and increasing the pharmacological activity of drugs. This paper discusses the features of using mobility shift affinity capillary electrophoresis for studying the strong complexation. Electrophoretic peaks for this case are often triangular. It was shown that the use of electrophoretic mobility obtained from the peak apex time in calculation of binding constants leads to significant systematic and random errors, and the parameter a 1 of the Haarhoff-Van der Linde function should be used instead of the apex time. Distorted triangular peaks with dips were shown to be observed at too high a ratio of analyte concentration in the sample to ligand concentration in the background electrolyte, and the peaks and parameter a 1 significantly shifted. It was found that the permissible excess of analyte concentration over ligand concentration is approximately 10-35, provided that the parameter a 1 is used, but the peak shape should be used as a landmark, and only triangular peaks without dips should be fitted with the function. The lowest possible analyte concentration should be utilized, which allows to use a wider range of ligand concentration leading to higher precision of determining the binding constants values. Kinetically labile 1:1 complexes between (2hydroxypropyl)-γ-cyclodextrin (HP-γ-CD) and betulin 3,28-diphthalate (DPhB) and betulin 3,28-disuccinate (DScB) were studied as an example. The binding constants logarithms at 25 °C are 7.23 ± 0.03 and 7.13 ± 0.10 for the HP-γ-CD complexes of DPhB and DScB, respectively.

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“…Data on the thermodynamic parameters of the complexation of betulin derivatives with CDs in aqueous solutions are fragmentary. Recently, the interaction of betulin derivatives with β‐CD and with (2‐hydroxypropyl)‐β‐cyclodextrin and HP‐γ‐CD has been studied using ACE and PS‐CZE. The binding (stability) constants of the complexes were determined at 25°C.…”

Section: Introductionmentioning

confidence: 99%

“…Most of the papers available in the literature deal with the properties of complexes of natural CDs. Papers concerning complexes of various compounds with CD derivatives, especially with (2‐hydroxypropyl)‐γ‐cyclodextrin (HP‐γ‐CD), are not numerous .…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic parameters for the complexation of water‐insoluble betulin derivatives with (2‐hydroxypropyl)‐γ‐cyclodextrin determined by phase‐solubility technique combined with capillary zone electrophoresis

2019

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The complexation of betulinic and betulonic acids (BIA and BOA) (pentacyclic lupane triterpenoids) with (2‐hydroxypropyl)‐γ‐cyclodextrin (HP‐γ‐CD) was studied at different temperatures using the method combining phase‐solubility technique and CZE. In contrast to mobility shift ACE utilizing the electrophoretic mobility, in this approach, the peak areas are used. The apparent binding (stability, formation) constants are obtained by the Higuchi and Connors method from the linear segment of compound solubility diagrams in CD solutions. It was found that the apparent binding constants of the HP‐γ‐CD complexes of BIA and BOA decrease with increasing temperature. The binding constants of BOA complexes are slightly higher than those of BIA complexes; this can be explained by difference in the hydration degrees of carbonyl and hydroxyl groups. On the basis of the binding constants obtained and their temperature dependences (van't Hoff plot), the enthalpy as well as entropy changes and Gibbs free energies were calculated. It was found that the complexation was characterized by negative changes of enthalpy and entropy, that is, it was controlled by enthalpy changes. The results obtained can be used for the optimization of microcapsulation processes of BOA and BIA with the HP‐γ‐CD application in order to increase solubility and bioavailability of these compounds.

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Solubility Study of Betulonic Acid in the Presence of Hydroxypropyl-γ-cyclodextrin by Capillary Electrophoresis

Cited by 7 publications

References 8 publications

Determining binding constants for 1:1 and 1:2 inclusion complexes of ester betulin derivatives with (2‐hydroxypropyl)‐β‐cyclodextrin by affinity capillary electrophoresis

Determining binding constants for 1:1 and 1:2 inclusion complexes of ester betulin derivatives with (2‐hydroxypropyl)‐β‐cyclodextrin by affinity capillary electrophoresis

Determination of binding constants for strong complexation by affinity capillary electrophoresis: the example of complexes of ester betulin derivatives with (2-hydroxypropyl)-γ-cyclodextrin

Thermodynamic parameters for the complexation of water‐insoluble betulin derivatives with (2‐hydroxypropyl)‐γ‐cyclodextrin determined by phase‐solubility technique combined with capillary zone electrophoresis

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