Proparacaine complexation with β-cyclodextrin and p-sulfonic acid calix[6]arene, as evaluated by varied 1H-NMR approaches
✍ Scribed by Lucas Micquéias Arantes; Camilla Scarelli; Anita Jocelyne Marsaioli; Eneida de Paula; Sergio Antonio Fernandes
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 145 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.2460
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✦ Synopsis
Abstract
This study focused on the use of NMR techniques as a tool for the investigation of complex formation between proparacaine and cyclodextrins (CDs) or p‐sulfonic acid calix[6]arene. The pH dependence of the complexation of proparacaine with β‐CD and p‐sulfonic acid calix[6]arene was studied and binding constants were determined by ^1^H NMR spectroscopy [diffusion‐ordered spectroscopy (DOSY)] for the charged and uncharged forms of the local anesthetic in β‐CD and p‐sulfonic acid calix[6]arene. The stoichiometries of the complexes was determined and rotating frame Overhauser enhancement spectroscopy (ROESY) 1D experiments revealed details of the molecular insertion of proparacaine into the β‐CD and p‐sulfonic acid calix[6]arene cavities. The results unambiguously demonstrate that pH is an important factor for the development of supramolecular architectures based on β‐CD and p‐sulfonic acid calix[6]arene as the host molecules. Such host–guest complexes were investigated in view of their potential use as new therapeutic formulations, designed to increase the bioavailability and/or to decrease the systemic toxicity of proparacaine in anesthesia procedures. Copyright © 2009 John Wiley & Sons, Ltd.