Self-Association of Cyclodextrins and Cyclodextrin Complexes

Loftsson, Þorsteinn; Másson, Már; Brewster, Marcus E.

doi:10.1002/jps.20047

Cited by 393 publications

(270 citation statements)

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“…These compounds have the ability to form inclusion complexes by taking up a whole molecule or rather some non polar parts in its hydrophobic cavity [3][4][5][6][7][8][9]. The driving forces between hosts and drugs which have been proposed to justify the complex formation are hydrogen bonds, van der Waals forces, hydrophobic interactions and the release of "high energy water" molecules from the cavity [10].…”

Section: Introductionmentioning

confidence: 99%

The influence of the preparation methods on the inclusion of model drugs in a β-cyclodextrin cavity

Salústio

Feio

Figueirinhas³

et al. 2009

European Journal of Pharmaceutics and Biopharmaceutics

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The work aims to prove the complexation of two models drugs (ibuprofen, IB and indomethacin, IN) by beta-cyclodextrin (βCD), the effect of the water in such process, and the comparison of their complexation yields. Two methods were considered: kneading of a binary mixture of the drug:βCD and inclusion of either IB or IN in aqueous solutions of βCD. In the latter method the water was removed by air stream, spray-drying and freeze-drying. To prove the formation of complexes in final products optical microscopy, UV spectroscopy, IR spectroscopy, DSC, X-Ray and NMR were considered. Each powder was added to an acidic solution (pH = 2) to quantify the concentration of the drug inside βCD cavity. Others media (pH = 5 and 7) were used to prove the existence of drug not complexed in each powder as the drugs solubility increases with the pH. It was observed that complexation occurred in all powders, and that the fraction of drug inside the βCD did not depend neither on the method of complexation nor on the processes of drying considered.

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Section: Introductionmentioning

confidence: 99%

The influence of the preparation methods on the inclusion of model drugs in a β-cyclodextrin cavity

Salústio

Feio

Figueirinhas³

et al. 2009

European Journal of Pharmaceutics and Biopharmaceutics

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“…Noting references to self-aggregation of cyclodextrins (Loftsson andBrewster, 1996, 2012;Loftsson et al, 2002Loftsson et al, , 2004Messner et al, 2010Messner et al, , 2011Jansook et al, 2010;Loftsson, 2014;He et al 2008), sizing experiments were carried out with fluorescein in the same carrier medium as that for ICT01-2588, pH 8.4 Tris buffer with 10% HP--CD-s2, and also in the Tris buffer without any added cyclodextrin. Fluorescein, conjugated to the peptide sequence via an isothiocyanate linker, is one of the functional end groups of ICT01-2588 (see Fig.…”

Section: Hydrodynamic Radius For Fluorescein In Tris Buffer and Tris mentioning

confidence: 99%

“…Formulae for cases where drugs bind more than one cyclodextrin are given in papers by Loftsson et al (2004) and Loftsson and Brewster (2012). Distribution calculations (data not shown) suggest that the highest fractions of the population of ICT01-2588 species involve multiple bound CDs, and may indicate that the hydrophilic, highly water soluble cyclodextrin HP--CD helps solubilise ICT01-2588 through binding to more than one of the end or side chain groups.…”

Section: Ict01-2588 Binding To Hp--cdmentioning

confidence: 99%

“…The types of aggregation in cyclodextrin drug systems have been extensively researched and reviewed by Loftsson and his collaborators (Loftsson andBrewster, 1996, 2012;Loftsson et al, 2002Loftsson et al, , 2004Messner et al, 2010Messner et al, , 2011Jansook et al, 2010;Loftsson, 2014), Supramolecular assemblies of amphiphilic cyclodextrins alone or in self-assembled mixtures with other molecules of therapeutic significance are described in a recent review by Zerkoune et al (2014). A bis-adamantine molecule which binds cyclodextrins at both ends and forms a hydrophilic -cyclodextrin bis-inclusion complex has been shown to selfassemble into supramolecular vesicles (Nayak and Gopidas, 2015).…”

Section: Aggregationmentioning

confidence: 99%

“…Cyclodextrins are often used to increase drug solubility through complex formation (Uekama et al, 1998). The ability of cyclodextrins to self-associate and the role of cyclodextrin-drug complexes and aggregates in solubilisation and delivery of drugs have been well documented in a series of papers by Loftsson and coworkers amongst others (Loftsson andBrewster, 1996, 2012;Loftsson et al, 2002Loftsson et al, , 2004Messner et al, 2010Messner et al, , 2011Jansook et al, 2010;Loftsson, 2014). The body of work showed that solubilisation and stabilisation of drugs in aqueous CD formulations are strongly influenced by other commonly used excipients.…”

Section: Introductionmentioning

confidence: 99%

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Characterisation of aggregates of cyclodextrin-drug complexes using Taylor Dispersion Analysis

Zaman

Bright

Adams

et al. 2017

International Journal of Pharmaceutics

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There is a need to understand the nature of aggregation of cyclodextrins (CDs) with guest molecules in increasingly complex formulation systems. To this end an innovative application of Taylor dispersion analysis (TDA) and comparison with dynamic light scattering (DLS) have been carried out to probe the nature of ICT01-2588 (ICT-2588), a novel tumor-targeted vascular disrupting agent, in solvents including a potential buffered formulation containing 10% hydroxypropyl-betacyclodextrin. The two hydrodynamic sizing techniques give measurement responses are that fundamentally different for aggregated solutions containing the target molecule, and the benefits of using TDA in conjunction with DLS are that systems are characterised through measurement of both mass-and z-average hydrodynamic radii. Whereas DLS measurements primarily resolve the large aggregates of ICT01-2588 in its formulation medium, methodology for TDA is described to determine the size and notably to quantify the proportion of monomers in the presence of large aggregates, and at the same time measure the formulation viscosity. Interestingly TDA and DLS have also distinguished between aggregate profiles formed using HP-beta-CD samples from different suppliers. The approach is expected to be widely applicable to this important class of drug formulations where drug solubility is enhanced by cyclodextrin and other excipients. To: The Editor, International Journal of Pharmaceutics From: Rob Forbes and David GoodallWe have revised the manuscript to reflect the amendments of the reviewers. The original cover letter is below.We are submitting this article, which describes novel work showing benefits of use of Taylor dispersion analysis in conjunction with dynamic light scattering to characterize ICT01-2588, a tumour-targeted vascular disrupting agent, in a potential formulation medium containing 10% hydroxypropyl--cyclodextrin as a solubility enhancing agent. Our approach is expected to be widely applicable to this important class of drug formulations where drug solubility is enhanced by cyclodextrin and other excipients, and is a contribution to advancing an understanding of the nature of self-assembly in such complex systems.The lead reviwer suggested is Thorsteinn Loftsson, who is a member of your Editorial Advisory Board. We cite a number of his papers. Of the other suggested referees. We cite work on Taylor dispersion analysis by the other two proposed referees, Ana Ribeiro and Jesper Ostergaard, and Robert HoylstPlease note that if possible we would like to name two corresponding authors, Robert T. Forbes (lead corresponding author) and David M. Goodall (second corresponding author). If this is not possible, it should be just Robert T. Forbes. The bulk of this work was conducted whilst Professor Forbes was at the University of Bradford, which is listed as his affiliation #1. He is currently at the University of Central Lancashire, which is listed as affiliation #2.Regarding declaration of conflict of interest guidelines, please note the foll...

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Electronic Circular Dichroism Spectroscopy

Zsila¹

2010

Pharmaceutical Sciences Encyclopedia

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Electronic circular dichroism (ECD or CD) is the manifestation of the important property of chiral compounds to absorb left and right circularly polarized light to different extents. Electronic circular dichroism (CD) spectroscopy technique has been used for investigation of chiral drugs and other pharmaceutical preparations. This article focuses on basic features, instrumentation, advantages, limitations, and practical applications of electronic circular dichroism (CD) spectroscopy in pharmaceutical sciences.

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Self-Association of Cyclodextrins and Cyclodextrin Complexes

Cited by 393 publications

References 53 publications

The influence of the preparation methods on the inclusion of model drugs in a β-cyclodextrin cavity

The influence of the preparation methods on the inclusion of model drugs in a β-cyclodextrin cavity

Characterisation of aggregates of cyclodextrin-drug complexes using Taylor Dispersion Analysis

Electronic Circular Dichroism Spectroscopy

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