Abstract: The aim of the present study is to enhance the solubility and stability of drugs in addition of water-soluble polymer and carbohydrate complexes. The data show that the polymer polyvinyl alcohol (PVA) interacts with the free Lamivudine and with the Lamivudine; β-cyclodextrin (β-CD) inclusion complex, in both cases with particular intermolecular interaction was studied using ultrasonic technique under different concentrations at a temperature 303 K. Consequently, the reason of this study was to improve the biological performance of the drug through enhancing its solubility and stability. The binary and ternary mixtures prepared inclusion complexes of Lamivudine in β-CD and PVA. The presence of PVA, changes the drug: β-CD interaction, a Lamivudine: β-CD: PVA complex was formed. In addition, the presence of PVA produces a strong increase in the binding constant at a particular concentration (1.25%). In the ternary complex, the Lamivudine is wrapped at both ends for the β-CD. In this complex, the polymer seems to act as a bridge between both β-CD molecules that bind the Lamivudine.