title: Proparacaine complexation with beta-cyclodextrin and p-sulfonic acid calix[6]arene, as evaluated by varied (1)H-NMR approaches.
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 beta-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 beta-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 beta-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 beta-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.
authors: Grupo de Química Supramolecular e Biomimética (GQSB), Departamento de Química, Universidade Federal de Viçosa (UFV), Viçosa, 36570-000, MG, Brazil.
authors: Lucas Micquéias
authors: LM
authors: Arantes
authors: Camilla
authors: C
authors: Scarelli
authors: Anita Jocelyne
authors: AJ
authors: Marsaioli
authors: Eneida
authors: E
authors: de Paula
authors: Sergio Antonio
authors: SA
authors: Fernandes
mesh_terms: D000779:Anesthetics, Local; D001665:Binding Sites; D047250:Calixarenes / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010636:Phenols / Q000737:chemistry*; D011430:Propoxycaine / Q000737:chemistry*; D013451:Sulfonic Acids / Q000737:chemistry; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000779:Anesthetics, Local; D010636:Phenols; D013451:Sulfonic Acids; D047392:beta-Cyclodextrins; C476540:calix(6)arene; D047250:Calixarenes; C005717:proxymetacaine; D011430:Propoxycaine