Food Packaging Materials for One-Dose Packaging for Enhanced Stability of Hygroscopic Medications

Background/Objectives: One-dose packaging is beneficial for older adults and those on multiple medications because it ensures that no doses are missed and supports medication adherence. However, conventional one-dose packaging materials have high moisture permeability, making them unsuitable for the storage of hygroscopic medications. We evaluated the barrier performance of food packaging materials against moisture and oxygen and investigated their potential to enhance the physical stability of the highly hygroscopic sodium valproate, under stressed storage conditions. Methods: Barrier performance was evaluated by measuring the water vapor transmission (WVTR) and oxygen transmission rates of each packaging material. Then, we evaluated the stability of sodium valproate tablets in different food packaging films by measuring weight change, breaking force, and visual appearance over 14 days under stressed storage conditions (35 °C and 75% relative humidity). Conventional cellophane-laminated polyethylene was used as the reference. Results: The WVTR of the food packaging films were below 2 g/m²/day, less than that of the conventional material. Tablets stored in Materials A and B showed weight increases of no more than 1.2% after 3 days, whereas the maximum increase among all food films was 3.7% (Material C). For Materials A and B, the breaking force remained measurable and the visual appearance unchanged throughout the 14-day period, whereas Material C became unmeasurable by day 14. Tablets packaged in cellophane-laminated polyethylene exhibited deliquescence, with visible deformation and stickiness within 3 days, rendering them unmeasurable. Conclusions: Food packaging materials with high barrier performance offer a practical, safe, and effective solution for one-dose packaging of hygroscopic medications, potentially expanding their clinical use and improving adherence.