Issue 37, 2021

Cyclodextrin complexes of the anticonvulsant agent valproic acid

Abstract

Six cyclodextrin (CD) complexes of the antiepileptic drug valproic acid (VAL) were prepared by kneading and/or co-precipitation methods and characterized by thermal analysis, powder X-ray diffraction and spectroscopic (1H NMR and FT-IR) techniques. The complexes (with host–guest stoichiometries in parentheses) included α-CD·VAL (2 : 1), β-CD·VAL (1 : 1), γ-CD·VAL (3 : 4), DMB·VAL (1 : 1), TMB·VAL (1 : 1) and TMA·VAL (1 : 1). Single crystal X-ray structures of four of the complexes were determined, those with β-CD and γ-CD featuring severely disordered guest molecules. Instead, the VAL molecules in the complexes with dimethylated β-CD (DMB) and permethylated α-CD (TMA) could be modelled, revealing modes of inclusion of valproic acid in CDs for the first time. The aqueous solubility values at 27 °C for VAL in the form of the solid complexes α-CD·VAL, β-CD·VAL and γ-CD·VAL were in the range 0.26–0.58 times that of the pure liquid phase of VAL. The merits of CD inclusion of VAL (e.g. transformation of the liquid guest into a solid, potential for reduction of adverse side effects) are discussed.

Graphical abstract: Cyclodextrin complexes of the anticonvulsant agent valproic acid

Supplementary files

Article information

Article type
Paper
Submitted
04 Aug. 2021
Accepted
01 Sept. 2021
First published
01 Sept. 2021

CrystEngComm, 2021,23, 6582-6590

Cyclodextrin complexes of the anticonvulsant agent valproic acid

A. I. Vicatos and M. R. Caira, CrystEngComm, 2021, 23, 6582 DOI: 10.1039/D1CE01024G

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