Effect of Temperature in Inclusion Complex Formation Between Amitriptyline Hydrochloride, as an Antidepressant Drug and β –Cyclodextrin in Water/n-Alcohol mixture

Cyclodextrins (CDs) are toroidally shaped oligosaccharides consisting of six to eight glucopyranose units connected with α(1→4) glycosidic bonds. The internal diameter of their relatively hydrophobic cavities, varying 5.7A° for α-CD to 7.8A° for β-CD and 10A° for γ-CD, allows inclusion complex formation selectivity to a certain degree, based on the gust size and structure .Interaction of drug with cyclodextrins is of biopharmaceutical interest. When drugs are administered as cyclodextrin complexes,dissolution, absorption, and bioavailability many be altered. The behavior of the inclusion complex consisting of Amitriptyline hydrochloride (AMH) and β-cyclodextrin was studied using conductometric technique. The results show that the stochemeteryof inclusion complex of β–CD with Amitriptyline was 1:1. The experiments were carried out at different temperatures and in different solvent compositions. Further investigation showed that K1 was decreased with increasing of hydrophobicity of solvents.The association constant values are used for evaluation of thermodynamic parameters of complexation, such as ΔG°, ΔH° and ΔS°.