Abstract
Host-guest complexation of dapoxyl sodium sulphonate (DSS), an intramolecular charge transfer dye with water-soluble and non-toxic macrocycle γ-cyclodextrin (γ-CD), has been investigated in a wide pH range. Steady-state absorption, fluorescence and time-resolved fluorescence measurements confirm the positioning of DSS into the hydrophobic cavity of γ-CD. A large fluorescence enhancement ca. 30 times, due to 1 : 2 complex formation and host-assisted guest-protonation have been utilised for developing a method for the utilisation of CD based drug-delivery applications. A simple fluorescence-displacement based approach is implemented at physiological pH for the assessment of binding strength of pharmaceutically useful small drug molecules (ibuprofen, paracetamol, methyl salicylate, salicylic acid, aspirin, and piroxicam) and six important antibiotic drugs (resazurin, thiamphenicol, chloramphenicol, ampicillin, kanamycin, and sorbic acid) with γ-CD.
Highlights
dapoxyl sodium sulphonate (DSS) was purchased from Invitrogen (USA); g-cyclodextrin (g-CD) and Na2HPO4 were purchased from Spectrochem (India); paracetamol, NaOH, NaCl, KCl and HCl were purchased from SDfine (India); salicylic acid was obtained from Merck (India); methyl salicylate was obtained from Loba Chemie (India); ibuprofen was obtained from Alfa-Aesar (India); piroxicam, aspirin, resazurin, sorbic acid, and thiamphenicol were purchased from Sigma-Aldrich (India), chloramphenicol, ampicillin, kanamycin were purchased from BR Biochem Life Science (India)
The quality of the fitted data was judged from the reduced chi-squared value (w2), which is calculated using the IBH software provided with the instrument
A displacement assay was performed in an aqueous solution at pH ca. 7.4 containing 5 mM DSS and 5 mM g-CD in a 1 ml fluorescence cuvette
Summary
Formulation of water-insoluble drugs with the help of watersoluble and non-toxic macrocyclic host molecules has received substantial interest.[1,2,3,4,5,6,7,8,9,10] The encapsulation of small drug molecules by water-soluble macrocyclic hosts due to non-covalent interactions can reinforce bioavailability and solubility by modulating their physical and chemical properties.[5,6,7,8] The encapsulation of drug molecules inside hydrophobic cavities leads to modulations of their solution properties, and this triggers the activation of the drug from its proactive form to its active state.[11,12,13,14] Supramolecular drug–macrocycle complexes have already been shown to have great promise for their usefulness in targeted drug delivery applications.[15,16,17]. Due to noncovalent interactions in the complex, the physical and chemical properties of the encapsulated molecules can be modulated to provide protection against photochemical and thermal decomposition, oxidation or hydrolysis.[22,23] The larger cavity size together with higher water-solubility compared to its homologues,[24,25] prompted us to select g-CD (see Fig. 1a), which is sufficiently spacious to accommodate moderate-to-large drug molecules for assessing its utility for drug-delivery applications. The modulated properties have been used to foster a novel, fluorescencebased and easy-to-perform turn-off fluorescence displacement method for assessing the drug-binding ability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
