Abstract
Cyclodextrins are very well known to form the inclusion complexes with various drugs owing to their internal cavity. In this paper we have studied the interaction of β-cyclodextrin (β-CD) with amphiphilic drug amitriptyline hydrochloride (AMT) exploiting conductometry, surface tensiometry and viscometry. It was found that addition of β-CD to the drug solution causes the shifting of micellization of amphiphilic drug toward higher concentrations. This confirms the complex formation between the drug and the host molecule as a result of the interaction between them. Surface tension isotherms suggest that the addition of β-CD results in the surface tension of the solution to decrease as compared to the pure solution of drug due to the encapsulation of surface active drug inside the hydrophobic cavity of β-CD. Similarly, viscosity of the solution decreases drastically on the addition of β-CD which further increased on increasing the drug concentration. Free energy of micellization (∆Gmic) was computed with the help of degrees of micelle ionization obtained from the specific conductivity−[AMT] plots.
► β-Cyclodextrin increases the critical micelle concentration of amitriptyline hydrochloride. ► Free energy of micellization suggests that the micellization becomes less favorable in presence of β-cyclodextrin. ► It was revealed from surface tension measurements that the complex was not surface active.