Study of the β‐Cyclodextrin Imipramine Hydrochloride Inclusion Complex and Determination of its Stability Constant (K) by UV‐Visible Spectroscopy

• Published in: E-journal of chemistry 2007-01, Vol.4 (4), p.550-558
• Main Authors: Ashnagar, Alamdar, Naseri, Nahid Gharib, Khanaki, Bita
• Format: Article
• Language: English
• ISSN: 2090-9063; 0973-4945; 2090-9071; 2090-9810
• DOI: 10.1155/2007/502718

In this research, the interactions of imipramine hydrochloride drug with β‐ cyclodextrin and the stability constant (K) of the inclusion complex formed between them were investigated by using UV‐visible spectroscopy. Solutions consisting of a known and constant amount of imipramine hydrochloride and varying amounts of β‐ cyclodextrin were prepared in 0.1 M phosphate buffer (pH 7.4). The final solutions had cyclodextrin concentrations between 0.0011 and 0.0153 M. UV‐visible spectra of each solution was taken at λ max = 250 nm. The absorbances at this wavelength were recorded and plotted against cyclodextrin concentrations. From the graph, the concentrations of free and bound imipramine hydrochloride and free β‐cyclodextrin were calculated using the Beer‐Lambert law. From these data, the stability constant was calculated and a value of K=52.26±11.41 mol -1 L was obtained. The magnitude of the stability constant is discussed in terms of the relative sizes and the chemical natures of β‐cyclodextrin and imipramine hydrochloride.