Magnetic Field-Dependent Changes in ORP and UV Absorption of Lactose Solutions with Different Pretreatment Histories

Lactose is widely used as a pharmaceutical excipient, yet little is known about how its physicochemical behavior may be influenced by pretreatment history and weak environmental magnetic conditions. In this pilot study, we investigated oxidation–reduction potential (ORP) and UV absorbance of 0.2% aqueous lactose solutions prepared from lactose powders with different pretreatment histories: Active water, Native water, and untreated control. Samples were exposed for 30 min to three static magnetic field conditions: weak geomagnetic field (~4 µT), ambient geomagnetic field (~30 µT), and elevated static field (~750 µT). UV/VIS spectroscopy was performed in the 200–400 nm range, with particular focus on the deep-UV absorption maximum near 200 nm. The strongest differentiation between pretreated samples and control occurred under weak geomagnetic conditions. In this weak-field regime, pretreated lactose solutions showed higher ORP values and a same-direction trend toward increased UV absorbance near 200 nm relative to untreated lactose. Across all samples, both ORP and UV absorbance decreased with increasing magnetic field strength, indicating a consistent field-dependent shift in the overall physicochemical state of the lactose solutions, particularly in redox balance and deep-UV optical response. The same-direction changes in ORP and increased 200 nm absorbance at the group level suggests that weak-field conditions may influence oxidation-related processes, potentially including the formation or stabilization of lactose oxidation products such as lactobionic acid. These findings indicate that lactose-containing aqueous systems may be sensitive to both pretreatment history and low-intensity magnetic environments, with potential implications for pharmaceutical formulation stability, quality control, and biotechnological reproducibility.