Photochemistry in Cyclodextrin Cavities

Bortolus, Pietro; Monti, Sandra

doi:10.1002/9780470133521.ch1

Cited by 86 publications

(19 citation statements)

References 347 publications

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“…Fluorescence has been extensively used to characterize the interaction of guests with host systems (56–58), because the shape of the emission spectrum, the fluorescence intensities and lifetimes are frequently dependent on the environment surrounding the fluorophore. The fluorescence of BP depends on the nature of the solvent.…”

Section: Resultsmentioning

confidence: 99%

Influence of Planarity and Size on Guest Binding with Sodium Cholate Aggregates

Waissbluth

Morales

Bohne

2006

Photochem & Photobiology

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Bile salt aggregates are supramolecular structures with two types of binding sites, called primary and secondary sites. The objective of this work was to explore how the nonplanarity and size of guests (biphenyl [BP], 1-1'-binaphthyl [BNP] and dibenz[b,f]oxepin [DBX]) affected their binding affinity and dynamics to sodium cholate (NaC) aggregates. Fluorescence and laser-flash photolysis experiments were performed to obtain information on the binding environment for the guests, the accessibility of quenchers to guests in the aggregate and the dissociation rate constants of the guests from the aggregates. All guests were bound to the more hydrophobic primary aggregate, showing that this site can accommodate nonplanar molecules. However, the structure of the guest affects the structure of the primary aggregates, leading to changes in the accessibility of anions to aggregate-bound guests and to changes for the guest dissociation rate constants from the aggregates.

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Section: Resultsmentioning

confidence: 99%

Influence of Planarity and Size on Guest Binding with Sodium Cholate Aggregates

Waissbluth

Morales

Bohne

2006

Photochem & Photobiology

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“…Biological targets are often very complex structures that require models of much less complexity to investigate the abovementioned aspects. Micelles, vesicles and cyclodextrins represent simple models for biological systems and investigation addressed at elucidating both binding and photochemical features in these media is an extremely active research area (41)(42)(43)(44)(45). However, to the best of our knowledge, little is known in this regard for FQ compounds (46,47).…”

Section: Introductionmentioning

confidence: 99%

Selective Entrapment of the Cationic Form of Norfloxacin within Anionic Sodium Dodecyl Sulfate Micelles at Physiological pH and its Effect on the Drug Photodecomposition†

Sortino

2006

Photochem Photobiol

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The binding of the photosensitizing fluoroquinolone (FQ) antibiotic norfloxacin (NX) to sodium dodecyl sulfate (SDS) micelles and the photoreactivity of the NX/SDS complex under physiological pH conditions are investigated by means of absorption and emission spectroscopy, steady-state and laser flash photolysis. It is shown that the photolabile zwitterionic form of NX, which is dominant at physiological pH, is not the most abundant species in the presence of SDS micelles. This medium exhibits a high preference for the cationic form of the drug, which is selectively and successfully entrapped within the micellar cage (K(ass) = 6 x 10(4) M(-1) +/- 3000), becoming the largely dominant species at neutral pH. The effect of this trapping is drastically reflected on both efficiency and nature of the drug photodecomposition. It is observed that the photostability of NX incorporated in the micellar pseudophase increases of more than one order of magnitude if compared to that of the "free" drug. Furthermore, the radical photodecomposition mechanism occurring in phosphate buffered solution is suppressed by the micellar medium and the low photodegradation observed seems to take place preferentially through an ionic pathway. Hopefully, the results presented herein may contribute to a better understanding of the bio-distribution of NX in biological systems and provide helpful and stimulating information in order to get the control of FQ photoreactivity under physiological pH conditions.

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“…The solvent effect on the photostability of curcumin is probably due to curcumin's ability to form inter‐ and intra‐molecular bondings, which might have a stabilizing or destabilizing effect on the molecule 29, 51. The mode of complexation between a drug and CDs will alter the microenvironment of the drug and thereby affect the photodegradation of the molecule incorporated or interacted with the CDs 52. Thus, CD‐inclusion complexation may have a stabilizing or a destabilizing effect on the photostability of drugs.…”

Section: Discussionmentioning

confidence: 99%