Comparative Disruption Behavior of Essential Oil and Fixed Oil Dietary Supplement Softgels Under Biorelevant Conditions.

Abstract

Softgel capsules are widely used in dietary supplements to deliver lipophilic ingredients, including essential and fixed oils. This study evaluated the disruption behavior of 104 commercially available softgel formulations under biorelevant conditions designed to approximate the gastrointestinal environment. Products were categorized as essential oil-containing (n = 40), fixed oil-containing (n = 48), combination (n = 6), and cannabidiol (CBD)-containing (n = 10) formulations. Disruption testing was conducted in biorelevant media, with enzyme supplementation applied according to shell composition when predefined rupture criteria were not achieved. Essential oil-containing softgels exhibited significantly lower pass rates than fixed oil formulations (35% vs 94%, χ², p < 0.0001). Shell composition also affected outcomes, as gelatin-based systems demonstrated higher overall pass rates than vegetable-based shells (77% vs 26%, χ², p < 0.0001). A partial rupture-resealing phenomenon characterized by transient fissuring and formation of a persistent hydrated pellicle was observed in certain products. Lot-to-lot variability was identified among selected formulations. These findings indicate that fill composition, shell material, and manufacturing variables contribute to disruption variability in dietary supplement softgels. Evaluation under physiologically informed testing conditions may reveal performance differences not evident under conventional water-based methods and may be particularly relevant for essential oil-containing formulations.