Investigation on the interaction between theophylline and alkaline substances using the DAOSD approach

The interaction between theophylline and ethylenediamine, choline hydroxide and other alkaline compounds was investigated via UV–Vis spectroscopic method. Upon introduction of alkaline compounds, the π-π transition band of theophylline undergoes a red shift. This phenomenon is a result of removing a proton from the 7-position of a theophylline molecule. Moreover, cross peaks appear in 2D asynchronous spectra generated via the DAOSD approach on theophyllinate and various cation systems. These results suggest that cation-π interaction and cation-anion interactions occur between theophyllinate and various cations including ethylenediamine, choline, tetramethyl ammonium, K+ and Cs+. The interaction between anionic theophyllinate and various cation may play a considerable role in the transmembrane transport of theophylline in medicinal process.