INCLUSION COMPLEXATION OF AMIDE-TYPED LOCAL-ANESTHETICS WITH BETA-CYCLODEXTRIN AND ITS DERIVATIVES .1. PHYSICOCHEMICAL CHARACTERIZATION

Qualitative aspects of the inclusion complexation of two local anaesth etics of the amide-type (LAs), bupivacaine (BVC) and lidocaine (LDC) w ith three cyclodextrins (CDs), beta-cyclodextrin (beta CD) and its alk ylated derivatives 2-hydroxypropyl-beta-cyclodextrin (HP beta CD) and heptakis (2,6-di-o-methyl)-beta-cyclodextrin (DM beta CD), were studie d in the solid state by infrared spectroscopy (IR) and differential sc anning calorimetry (DSC). The LDC-beta CD couple was also investigated in aqueous solution by nuclear magnetic resonance (H-1-NMR and C-13-N MR). This first part of a study dealing with improvement in LA adminis tration provided clear indications about LA-CD complexation. Qualitati ve modifications in a number of peaks or bands obtained from spectral methods as well as thermal analysis signed the inclusion, showing that the freeze-drying method was suitable for obtaining inclusion complex es of LAs with CDs.