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

Abstract

Binary and ternary systems composed of dapsone, sulfobutylether-β-cyclodextrin (SBE-β-CD), β-CD and egg phosphatidylcholine (EPC) were evaluated using 1D ROESY, saturation transfer difference NMR and diffusion experiments (DOSY) revealing the binary complexes Dap/β-CD (K(a) 1396 l mol(-1)), Dap/SBE-β-CD (K(a) 246 l mol(-1)), Dap/EPC (K(a) 84 l mol(-1)) and the ternary complex Dap/β-CD/EPC (K(a) 18 l mol(-1)) in which dapsone is more soluble.

Do Cyclodextrins Encapsulate Volatiles in Deep Eutectic Systems?

“…This means that in the presence of a complex, the diffusion of the encapsulated molecule will be slower than that measured for the free compound. DOSY maps are well suited to study aggregation and quantify molecular interactions in chemical systems, ,− and many examples can be found in the literature where DOSY NMR has been used to investigate the structure, stoichiometry, host bound and unbound fractions to guests, association binding constant, and host–guest relative positioning in CD complexes. ,,− DOSY maps were acquired for samples 1 to 4 (Fig. S4).…”

“…Assuming a rapidly equilibrating system, the diffusion coefficients are weight-averaged NMR values between free and bound species. In this condition, diffusion coefficients measured using DOSY experiments for the guest molecule, D G obs , can be used to calculate the molar fraction of the bound guest x G bound and apparent association constants K a of host–guest complexes (see the Supporting Information for a theoretical treatment). ,,− In brief, the observed diffusion coefficients ( D G obs ) of AN and Tol measured in the equimolar host–guest mixtures (samples 5 and 7 ) are the averaged values weighed by mole fractions of their bound and free molecules. The diffusion coefficients of free guests, D G free , can be measured directly in the absence of the host (samples 6 and 8 ).…”

Inclusion Complex between Local Anesthetic/2-hydroxypropyl-β-cyclodextrin in Stealth Liposome

“…With the aid of the 1 H STD technique, it was observed that prilocaine was released from βCD to liposome vesicles, and the formation of the PLC-Liposomes complex was higher at pH 10. Martins et al [34] observed a strong interaction between the antibiotic dapsone and egg phosphatidylcholine liposome (EPCL), with the complete insertion of dapsone in the lipid bilayer of the liposome.…”