The Determination of Non-covalent Complexes of Diclofenac Sodium and Cyclodextrins by Electrospray Ionization/Time-of-Flight Mass Spectrometry

Abstract

The formation of the gas-phase non-covalent complexes of diclofenac sodium with cyclodextrins (CDs) was studied by electrospray ionization/time-of-flight mass spectrometry (ESI/TOFMS). The continuous variation method was utilized to elucidate the stoichiometry. Mass spectrums revealed the stoichiometric ratios of complexes with 1:1, 2:1, 3:1 and 1:2 (b-cyclodextrin:diclofenac sodium) in deionized water or ethanol. The influence of cavity size of CD and the pH values of solution on the mixture system were investigated in detail. Only one complex peak was observed in a-CD, which is different from band g-CD. These results demonstrated that ESI/ TOFMS is a complementary technique for study of the non-covalent complex.

Electrospray Ionization Mass Spectrometric Analysis of Noncovalent Complexes of Hydroxypropyl-β-cyclodextrin and β-Cyclodextrin with Progesterone

“…In addition, ions corresponding to higher ratio complexes were also observed. These higher order noncovalent complex patterns of some guest molecules with CDs or their derivatives have been often observed in supramolecular chemistry using mass spectrometry in the pattern of specific noncovalent complex [19][20][21][22][23] or nonspecific ones. [24][25][26] Although the complex of β-CD-progesterone with stoichiometry of 1:1 was thermodynamically characterized using differential pulse polarography, 18 higher complex ratios between β-CD and progesterone formed in mixture of ) complexes, respectively.…”