Preparation, characterization and binding behaviors of host-guest inclusion complexes of metoclopramide hydrochloride with α- and β-cyclodextrin molecules

• Published in: Journal of molecular structure Vol. 1155; pp. 503 - 512
• Main Authors: Barman, Siti, Barman, Biraj Kumar, Roy, Mahendra Nath
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.03.2018
• Subjects: Association constant; Cyclodextrin; Inclusion complex; Job's plot; Metoclopramide hydrochloride; Supramolecular study; Association constant; Job's plot; Cyclodextrin; Supramolecular study; Metoclopramide hydrochloride; Inclusion complex
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2017.11.041

The supramolecular interaction of metoclopramide hydrochloride (MP) with α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD) has been inspected by ultraviolet–visible (UV–vis) light, infra-red (IR) light, fluorescence and 1H NMR spectroscopy. The formation of an inclusion complex greatly affects the physical–chemical properties of the guest molecules, such as solubility, chemical reactivity and the spectroscopic and electrochemical properties. Thus the changes in the spectral properties and physico-chemical properties confirm the inclusion complex formation. Surface tension, conductivity studies and Job's plot indicate a 1: 1 stoichiometry of the MP:CD host–guest inclusion complexes. The binding/association constants have been evaluated by both UV–Vis and fluorescence spectroscopic study indicating a higher degree of encapsulation for β-cyclodextrin (β-CD). Furthermore, the negative value of thermodynamic parameter (ΔG°) of the host-guest system suggests that the inclusion process proceeded spontaneously at 298.15 K. Based on the NMR data, the plausible mode of interaction of MP:α-CD and MP:β-CD complexes were proposed, which suggested that lipophilic aromatic ring of the MP entered into the cavity of CDs from the wider side, with the amide (CONH) and methoxy (-OMe) residues inside the CD cavity. [Display omitted] •1:1 inclusion complex formation of MP with α and β-CD are shown.•The inclusion behavior was studied by fluorescence, UV, FT-IR, MS and NMR.•Host–guest complex formation changed the physicochemical properties of free drug.•The various factors affecting the inclusion process were examined in detail.•Van der Waals, hydrophobic and hydrogen bonding interactions play a vital role.