Supramolecular Interactions of a Biguanide-Type Antidiabetic Drug and <scp>d</scp> -(+)-Glucose in Aqueous Solution: Exploring the Role of Temperature and Concentration

In this work, volumetric, acoustic, viscometric, photon correlation, and near-infrared spectroscopic studies of a biguanide-type antidiabetic drug, metformin hydrochloride (M·HCl), have been reported for binary solutions with water and ternary solutions with d-(+)-glucose in aqueous media. The volumetric and acoustic studies show a kosmotropic nature of M·HCl in aqueous systems (from 0.1534 × 10–3 mol·kg–1 to 60.9483 × 10–3 mol·kg–1). Structure breaking progresses with increasing temperature (from 290.0 to 330.0 K). Strong interactions between M·HCl and water are revealed by viscometric analysis, and compared to the transition state, the ground state shows more prominent interactions. Again, the studies unveil that water structure breaking occurs with the addition of d-(+)-glucose molecules for ternary systems (up to 10.0 × 10–3 mol·kg–1). Self-association of glucose occurs with an increasing concentration of d-(+)-glucose. Water molecules surround glucose molecules more, and the kosmotropic nature of M·HCl is observed (from 10.0 × 10–3 mol·kg–1 to 20.0 × 10–3 mol·kg–1). Photon correlation and near-infrared spectroscopy studies also yielded the same result. Structure making progresses with rising temperature (from 290.0 to 315.0 K), but a rise to a greater extent (from 315.0 to 330.0 K) leads to the breaking of the water structure.