Chronocoulometry diffusion coefficients as a measure of cyclodextrin–estradiol complex association

Yáñez, Claudia; Basquinzay, R.

doi:10.1016/j.jelechem.2008.06.005

Cited by 11 publications

(5 citation statements)

References 14 publications

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“…Although SEC-MALS also reveals that 4·nPF 6 aggregates strongly in solution, the conformation plots do not indicate the presence of any spherical nanoparticles in solution. In a series of independent measurements, [22] diffusion coefficients (D 0 ) of (1.15 AE 0.05) 10 À12 m 2 s À1 for 5·nPF 6 and (1.51 AE 0.06) 10 À9 m 2 s À1 for 3·4PF 6 were measured by double potential step chronocoulometry [23] (see Supporting Information) in DMF at 298 K and applying the Cottrell relationship. [24] Dynamic light scattering (DLS) measured a diffusion coefficient of (2.22 AE 0.21) 10 À12 m 2 s À1 for 5·nPF 6 , and a hydrodynamic radius (R h ) of 174(AE32) nm, yielding an R g /R h value of 0.730(AE0.13)-again indicating [25] the prescence of spherical particles in solution.…”

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confidence: 99%

A Bistable Poly[2]catenane Forms Nanosuperstructures

et al. 2009

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Side‐chain poly[2]catenanes at the click of a switch! A bistable side‐chain poly[2]catenane has been synthesized and found to form hierarchical self‐assembled hollow superstructures of nanoscale dimensions in solution. Molecular electromechanical switching (see picture) of the material is demonstrated, and the ground‐state equilibrium thermodynamics and switching kinetics are examined as the initial steps towards processible molecular‐based electronic devices and nanoelectromechanical systems.

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confidence: 99%

A Bistable Poly[2]catenane Forms Nanosuperstructures

et al. 2009

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“…Consequently, interaction between -CD and the steroids was weakened when acetonitrile was used. The formation of inclusion complexes between estradiol and sulfobutyleter--CD (SBCD) and hydroxypropil--CD (HPCD) has been also studied by chronocoulometric and differential pulse voltammetry [69]. In presence of CD there was a decrease of the cathodic peak current with the increase of the amount of CD.…”

Section: Electrochemicalmentioning

confidence: 99%

Electrochemistry of Cyclodextrin Inclusion Complexes of Pharmaceutical Compounds

Radi¹

2010

TOCBMJ

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Electrochemistry of cyclodextrins (CDs) and cyclodextrin inclusion complexes with different pharmaceutical compounds is reviewed. The article highlights some electrochemical investigations of the CD-drugs interactions in solution. Cyclodextrin modified electrodes and their applications as electrochemical sensors in pharmaceutical analysis based on the self-assembly of CD derivatives on metal electrodes and nanoparticles, and cyclodextrin-modified multiwalled carbon nanotubes are also discussed.

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“…A substantial volume of research on the topic of CD inclusion of BES and PRO has already been published, the majority of the publications being focused on medicinal applications, for example, using formulations of these drugs with CDs for ophthalmic and nasal delivery [11][12][13][14][15][16][17][18][19][20][21]. The scientific literature abounds with reports featuring the use of a wide variety of analytical and confirmatory techniques [22][23][24][25][26][27][28] as well as solubility analyses [29][30][31][32][33][34][35][36][37][38] to investigate the physicochemical properties of CD inclusion complexes and multicomponent CD inclusion systems based on numerous derivatised CDs containing BES and PRO, thus confirming the sustained interest in this approach and its significance in drug delivery. Previous studies of the complexation of BES, PRO and related compounds by CDs in the solution phase have typically reported the use of NMR spectroscopy to investigate complex formation, complex structure, stoichiometry and association constants via the detection and measurement of small deviations in the 1 H NMR chemical shifts for both host and guest molecules upon complexation.…”

Section: Introductionmentioning

confidence: 99%

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

Vicatos¹,

Hoossen²,

Caira³

2022

Beilstein J. Org. Chem.

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Overcoming the challenges of poor aqueous solubility of active pharmaceutical ingredients (APIs) is necessary to render them bioavailable. This study addresses the poor solubility of two potent steroid hormones, 17β-estradiol (BES) and progesterone (PRO), via their complexation with two water-soluble native cyclodextrins (CDs) namely β-CD and γ-CD. The hydrated inclusion complexes β-CD·BES, β-CD·PRO, γ-CD·BES and γ-CD·PRO were prepared via kneading and co-precipitation, and 1H NMR spectroscopic analysis of solutions of their pure complex crystals yielded the host–guest stoichiometries 2:1, 2:1, 1:1 and 3:2, respectively. Both powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction (SCXRD) were employed for focused studies of the isostructurality of the CD complexes with known complexes and structural elucidation of the new complexes, respectively. SCXRD analyses of β-CD·BES, β-CD·PRO and γ-CD·PRO at 100(2) K yielded the first crystal structures of CD complexes containing the hormones BES and PRO, while the complex γ-CD·BES was readily shown to be isostructural with γ-CD·PRO by PXRD. Severe disorder of the encapsulated steroid molecules in the respective channels of the CD molecular assemblies was evident, however, preventing their modelling, but combination of the host–guest stoichiometries and water contents of the four hydrated inclusion complexes enabled accurate assignment of the chemical formulae of these ternary systems. Predicted electron counts for the complexed molecules BES and PRO correlated reasonably well with the complex compositions indicated by 1H NMR spectroscopy. Subsequent measurements of the aqueous solubilities of the four complexes confirmed significant solubility improvements effected by encapsulation of the steroids within the CDs, yielding solubility enhancement factors for BES and PRO in the approximate range 5–20.

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Chronocoulometry diffusion coefficients as a measure of cyclodextrin–estradiol complex association

Cited by 11 publications

References 14 publications

A Bistable Poly[2]catenane Forms Nanosuperstructures

A Bistable Poly[2]catenane Forms Nanosuperstructures

Electrochemistry of Cyclodextrin Inclusion Complexes of Pharmaceutical Compounds

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

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