PHYSICOCHEMICAL CHARACTERIZATION OF DIFFERENT BATCHES OF ETHYLATED BETA-CYCLODEXTRINS

Different ethylated beta-cyclodextrin (Et-beta-CD) derivatives were ob tained by various synthetic routes and their chemical structures and p hysical properties were elucidated. The aqueous solubility studies wer e carried out at 25 and 37 degrees C. A gas phase chromatography analy sis, with head space extraction, was developed to detect the presence of residual solvents in the dry preparations. Electrospray ionization mass spectrometry allowed the determination of the average degree of s ubstitution and the molecular mass of the Et-beta-CDs. Nuclear magneti c resonance analysis was used to elucidate the relationship between th e solubility behavior and substituted positions of ethyl groups on the CD glucopyranose units. Finally, this paper deals with different phys icochemical methods used to fully characterize the different batches o f Et-beta-CD to correlate the data obtained with the pharmacotechnical behavior of these cyclodextrins.