Analytical investigation of solubility and solid-state transformation of Amikacin sulphate in magnetized water compared with organic solvents

The present work investigates the solubility of amikacin sulphate in five solvents, namely magnetized water, distilled water, methanol, ethanol, and propanol, over a range of temperatures of 298.15-328.15 K. To perform the measurements, the gravimetric method was used. The results showed an apparent solvent-dependent behaviour. Magnetized water consistently exhibited the highest solubility of amikacin sulphate among the tested temperatures. At 328.15 K, the mole fraction solubility in magnetized water reached 33.945 ×10⁻³, whereas it was 21.258 ×10⁻³ and 11.866 ×10⁻³ in distilled water and propanol, respectively. The findings were acceptable using both the modified Apelblat equation (R² = 0.99468) and the Van’t Hoff model, enabling the extraction of thermodynamic parameters. Moreover, the dissolution in magnetized water was characterized by a negative Gibbs free energy (ΔG= –51.301 kJ mol-1) and a high positive entropy change (ΔS = 65.588 J/mol. K). This will suggest a spontaneous and entropy-driven process. Additionally, scanning electron microscopy (SEM) images showed a reduction in particle size to 16.29-30.91 nm at 25 °C in magnetized water, and to 18.10-26.45 nm at 55 °C. The tests of X-ray diffraction (XRD), Thermogravimetric analysis and Differential Scanning Calorimetry (TGA and DSC) further confirmed an improved amorphous character with enhanced thermal stability. These findings clearly indicate that magnetized water is a highly effective medium for dissolving amikacin sulphate. This could motivate research into the implications of magnetized water for improving bioavailability in pharmaceutical formulations.