Bioavailability of Thymol Incorporated into Gastro-Resistant Self-Emulsifying Pellets in Rabbits

Thymol gastro-resistant self-emulsifying pellets were used to achieve thymol targeted release on the side of the intestine with the most intensive absorption to enhance its oral bioavailability. Forty-eight rabbits (35 d of age) were divided into two groups fed with a standard diet containing gastro-resistant enteric pellets (control, CG; without thymol, initial live weight 1350.0 +/- 18.0, and experimental, EG; with thymol 250 mg/kg, initial live weight 1352.0 +/- 19.9 g). The experiment lasted 28 days: thymol was administered for 21 days and then withdrawn for 7 days. Thymol was significantly higher in duodenal wall (DW) than in plasma during both periods (p = 0.0053, p < 0.0001). Significant correlation was established between thymol concentration in plasma and DW during its application (rs = 0.9333, p < 0.001). Thymol was below the limit of quantitation in plasma, spleen and muscle only after its withdrawal, and its significantly higher concentration in kidney and fat than in plasma (p = 0.0182, p = 0.0003) and muscle (p = 0.0236, p = 0.0004) indicates its efficient accumulation. Thymol in gastro-resistant form prevented its degradation due to adverse conditions in the stomach and ensured its release at the site of greatest absorption in the small intestine.

Slovak Academy of Sciences
University of Veterinary Medicine and Pharmacy in Košice
National Agricultural and Food Centre
City College of New York