Rigidity versus flexibility. A review of experimental and theoretical studies pertaining to the cyclodextrin nonrigidity

Dodziuk, Helena

doi:10.1016/s0022-2860(02)00236-3

Cited by 69 publications

(53 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12 The molecular volume is the main restrictive factor of the inclusion process of sunscreens in the cavity of cyclodextrins. 32 The molecular volume of OMC, calculated by molecular modeling, was larger (367.53 Å 3 ) than the cavity of the β-CD (cavity volume = 262 Å 3 ). 20 The inclusion of OMC in α-CD (174 Å 3 ) produces low reproducibility and yield; however, the use of γ-CD (472 Å 3 ) produces an increase in the yield (20%).…”

Section: Lipo/omc Complex Characterizationmentioning

confidence: 92%

Evaluation of octyl p-methoxycinnamate included in liposomes and cyclodextrins in anti-solar preparations: preparations, characterizations and in vitro penetration studies

Monteiro¹,

Ozzetti²,

Vergnanini³

et al. 2012

IJN

View full text Add to dashboard Cite

Purpose: Awareness of the harmful effects of ultraviolet radiation has led to the increasing use of sunscreens, thus, the development of safe and effective antisolar preparations is important. The inclusion of sunscreen molecules in different release systems, like liposomes (lipo) and cyclodextrins (CD) is therefore required. Methods: The in vivo sun protection factor (SPF), water resistance, and in vitro transdermal penetration test of octyl p-methoxycinnamate (OMC) in different dispersions, such as OMC encapsulated in liposomes (lipo/OMC), OMC encapsulated in β-cyclodextrins (β-CD/OMC), OMC encapsulated in both release systems (lipo/OMC and β-CD/OMC), and an OMC-free formulation were determined. Results: Although the formulation containing only the lipo/OMC system revealed high value of in vivo SPF (11.0 ± 1.3) and water resistance (SPF = 10.3 ± 2.2), the formulation containing both release systems (lipo/OMC + β-cyclodextrin/OMC) showed the best result in the in vivo SPF test (11.6 ± 1.6). In the penetration test, the formulation containing the lipo/OMC system had better performance, since a high amount of OMC in the epidermis (18.04 ± 1.17 µg) and a low amount of OMC in the dermis (9.4 ± 2.36 µg) were observed. These results suggest that liposomes interact with the cells of the stratum corneum, promoting retention of OMC in this layer. Conclusion: According to our study, the lipo/OMC system is the most advantageous release system, due to its ability to both increase the amount of OMC in the epidermis and decrease the risk of percutaneous absorption.

show abstract

Section: Lipo/omc Complex Characterizationmentioning

confidence: 92%

Evaluation of octyl p-methoxycinnamate included in liposomes and cyclodextrins in anti-solar preparations: preparations, characterizations and in vitro penetration studies

Monteiro¹,

Ozzetti²,

Vergnanini³

et al. 2012

IJN

View full text Add to dashboard Cite

show abstract

“…5, 2007 The phenomenon of conformational flexibility in CDs is still nowadays matter of debate. 73 For a long while CD molecules have been considered conformationally quite rigid, but this view has undergone revisions. 73,74 Supporting the latter is the ability of CDs to accommodate themselves to the spatial and electronic character of a wide variety of guests.…”

mentioning

confidence: 99%

“…The highly symmetrical representation of these cyclic carbohydrates is in contrast to their physicochemical plasticity. [1][2][3][4][5][6]73 Most of the discussions about CDs flexibility have been based on crystallographic information obtained from solid state studies or gas-phase analyses, as discussed in the review by Dodziuk. 73 The presence of H-bonds between the neighbor secondary hydroxyl groups OH2 and OH3 is generally considered a factor that enhance the rigidity of these cyclic molecules.…”

mentioning

confidence: 99%

“…[1][2][3][4][5][6]73 Most of the discussions about CDs flexibility have been based on crystallographic information obtained from solid state studies or gas-phase analyses, as discussed in the review by Dodziuk. 73 The presence of H-bonds between the neighbor secondary hydroxyl groups OH2 and OH3 is generally considered a factor that enhance the rigidity of these cyclic molecules. 10,75 In studies concerning CDs conformational flexibility, the inter-glucose H-bonds are normally considered to be the dominant factor for the macrocycle rigidity, having influence even on the conformational space defined by ψ and φ.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Revisiting the internal conformational dynamics and solvation properties of cyclodextrins

Pereira¹,

Moura²,

Freitas³

et al. 2007

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Simulações de dinâmica molecular são utilizadas para investigar a dinâmica conformacional interna e propriedades de solvatação das três ciclodextrinas naturais, α-, β-e γ-ciclodextrina em água e temperatura ambiente. Estes oligossacarídeos derivados da glicose apresentam uma estrutura molecular peculiar que lhes confere a habilidade de formar complexos de inclusão e modificar as propriedades físico-químicas das moléculas complexadas. As características estruturais das ciclodextrinas em solução são determinantes para a complexação. As análises das trajetórias obtidas mostram que ligações de hidrogênio secundárias entre resíduos de glicose adjacentes estão presentes em solução e apresentam um caráter altamente dinâmico, onde ligações de hidrogênio alternativas podem ser formadas com moléculas de água. Apesar do baixo caráter hidrofílico, as cavidades apresentam-se solvatadas e o número de moléculas de água dentro da cavidade é aproximadamente duplicada por unidade de glicose adicionada ao macrociclo. Os tempos de residência para as moléculas de água dentro das cavidades são inversamente proporcionais ao seu respectivo tamanho.Molecular dynamics simulations were used to investigate the internal conformational dynamics and solvation properties of the three natural cyclodextrins, α-, β-and γ-cyclodextrin in aqueous solution at room temperature. These glucose-derived oligosacharides present a molecular structure that confers them the ability to complex guest molecules and change their physicochemical properties. The structural behavior of cyclodextrins in solution is crucial for their complexation abilities. Analyses of the obtained trajectories show that inter-glucose hydrogen bonds between the secondary hydroxyl groups are present in solution, but show a very dynamical character where alternative hydrogen bonds to water molecules can be formed. Despite the lower hydrophilicity of the cyclodextrins inner-cavities, they were found to be solvated and the number of water molecules inside the cavity roughly doubles per glucose unit added to the ring. The residence times for water molecules inside the cavities are inversely proportional to the cavity size. Keywords: cyclodextrins, molecular dynamics, solvation, flexibility IntroductionCyclodextrins (CDs) have been extensively studied since their discovery in the late nineteenth century.1 Their peculiar properties and behavior have interested scientists in many different fields.2 These cyclic oligosaccharides, obtained from starch by glucanotransferase degradation, are formed by a certain number of α-D-glucopyranose units linked by α(1→4) glycosidic bonds. This arrangement produces a truncated cone shape with a central cavity relatively hydrophobic and an external surface relatively hydrophilic.1-3 Naturally occurring CDs, known as α-, β-and γ-CD, present six, seven and eight glucose units, respectively.1-3 The structural features of these saccharides allow them to form inclusion complexes with a great variety of compounds.3 Due to their ability to form host-guest complexe...

show abstract

“…An inhibiting property of β-CD has been its relatively low solubility in water compared with those of α-and γ-CDs that are nine and eleven times more soluble, respectively [1][2][3][4][5]. Therefore, a detailed understanding, based on molecular mechanisms, of the anomalous behavior of β-CD is important for catalytic, industrial, and pharmaceutical applications of CDs [4,5]. Diphenyl sulphone derivatives are found to be pharmaceutically and industrially important.…”

Section: Introductionmentioning

confidence: 99%

Quantifying the Possible Short- and Long-term Impacts of Superoxide Redox Chemistry on Seawater pH

2015

Can Chem Trans

View full text Add to dashboard Cite

Absorption, steady state and time resolved fluorescence spectra of 4,4′-sulfonyldiphenol (SDP), 3,3'-dimethyl 4,4′-sulfonyldiphenol (DMSP), 4,4′-sulfonyldibenzoic acid (SDBA) were studied in the presence of α-and β-cyclodextrins. Both in water and CD, SDP and SDBA exhibit two emission maxima while DMSP exhibit three emission maxima. In β-CD, the rate of enhancement of longer wavelength (LW) emission is higher than that of shorter wavelength (SW) band, where as in α-CD the enhancement of SW is larger than that of LW. The normal Stokes shifted band was originated from the locally excited state and the large Stokes shifted band was due to the emission form a TICT state. In these molecules, the presence of OH or COOH groups at para position of the aromatic rings increase the coplanar geometry in the excited state. Semi-empirical quantum-mechanical calculations were also carried out to assign the encapsulation of the SDP, DMSP and SDBA. PM3 calculations show that most of the SDBA values are different from SDP and DMSP because the values are dependent on the size of the CD cavities and nature of the functional group of the guest.

show abstract

Rigidity versus flexibility. A review of experimental and theoretical studies pertaining to the cyclodextrin nonrigidity

Cited by 69 publications

References 60 publications

Evaluation of octyl p-methoxycinnamate included in liposomes and cyclodextrins in anti-solar preparations: preparations, characterizations and in vitro penetration studies

Evaluation of octyl p-methoxycinnamate included in liposomes and cyclodextrins in anti-solar preparations: preparations, characterizations and in vitro penetration studies

Revisiting the internal conformational dynamics and solvation properties of cyclodextrins

Quantifying the Possible Short- and Long-term Impacts of Superoxide Redox Chemistry on Seawater pH

Contact Info

Product

Resources

About