Host–guest interactions between dapsone and β-cyclodextrin (Part II): thermal analysis, spectroscopic characterization, and solubility studies

1 H NMR studies of binary and ternary dapsone supramolecular complexes with different drug carriers: EPC liposome, SBE-β -CD and β -CD

“…However, our aim to evaluate the change in chemical shift is only qualitative because the strength of the interaction was studied from variation in the diffusion coefficient of substances. The Dap / β ‐CD complex has been previously characterised; however, its characterisation on the same experimental conditions used for all drug carriers addressed in this study was important for better data comparison. Moreover, these data have to be consistent for a better understanding of the ternary complex formation containing Dap, EPCL and β ‐CD.…”

“…Analogous behaviour was observed for both Ha and Hb in the absence and presence of SBE‐ β ‐CD, changing T 1 from 2.84 to 1.59 s and from 3.29 to 1.85 s, respectively. The Dap / β ‐CD and Dap / SBE‐ β ‐CD stoichiometries were determined using the Job's plot method, which derives from the NMR analyses. The concentration sum of Dap and β ‐CD (or SBE‐ β ‐CD ) was maintained at 2 mmol l −1 , and the formation of the 1 : 1 complexes for Dap / β ‐CD and Dap / SBE‐ β ‐CD was observed, as described in the preceding texts for the Dap / β ‐CD complex (Fig.…”

“…Dap and β ‐cyclodextrin ( β ‐CD) interactions have been studied by applying different methodologies, and their apparent association constants in the presence and absence of various linear alcohols were determined by spectrofluorimetry . Dap‐ β ‐CD complex stoichiometry has been reported, and several structural models were proposed based on emission spectroscopy and nuclear magnetic resonance (NMR) experiments. Additionally, ternary systems composed of Dap, polyvinylpyrrolidone K30 or hydroxypropyl methylcellulose, and β ‐CD or 1‐HP‐ β ‐CD were investigated to improve Dap solubility and bioavailability .…”

Enhanced solubility of galangin based on the complexation with methylated microbial cyclosophoraoses

“…The phase solubility study (data not shown) of b-CD, DM-b-CD, Cys, and M-Cys complex with galangin clearly showed that the solubility of galangin was noticeably enhanced as the concentration of M-Cys increased. The galangin/M-Cys complex formed typical A L -type curves, indicating a 1:1 stoichiometry [35,36]. Furthermore, the apparent binding values of the various complexes calculated from phase solubility are shown in Table 2 more efficient complexation than that of DM-b-CD.…”

Imiquimod/β-Cyclodextrin Inclusion Complex: Experimental and Theoretical Studies

“…Negative entropy usually describe guest molecule that is partially inserted into cyclodextrin cavity or whose movement is restricted due to strong interactions with the host molecule which decrease its degree of freedom. 47 It should be mentioned that the low entropy value found for βCD (flx) molecule was due to the greater packaging of this form when optimized under solvent conditions; βCD optimized geometries, βCD (flx) and βCD (frz), are depicted in Figure S7 in the SI section.…”