Pharmacokinetic fate of 14C‐Labelled fumonisin B1 in Swine

Abstract

The pharmacokinetics of the mycotoxin fumonisn B₁ (FB₁) were investigated in pigs. Animals were administered ¹⁴C-FB₁ intravenously (IV; 0.25 μCi, 0.40 mg/kg) or intragastrically (IG;0.35 μCi, 0.50 mg/kg); separate groups of pigs undewent bile cannulation prior to dosing (groups IV/B and IG/B, respectively). Blood, urine, faeces, (and bile), were collected at specific time intervals over 72 gr, and assayed for specific activity. Following IV dosing, plasma concentration-time profiles were triexponential, with the following mean values: t½ α, 2.2 min; t½ β, 10.5 min; t½ γ 182 min; apparent volume distribution (Vdγ), 2.4 1 kg⁻¹; plasmaclearance, 9.1 ml min⁻¹ kg⁻¹. After 3 days, clearance of FB₁-derived radioactivity from the body had slowed to trace levels; total recoveries in urine and faeces were 21.2% and 58.3%, respectively. In bile-interruped pigs (IV/B) the absence of the slow terminal elimination phase (γ) suggested FB₁ underwent enterohepatic circulation. Biliary recovery was 70.8% of the IV-dose. Radioactivity remaining in tissues after 72 hr amounted to 19.8% and 11.9% of the dose given to IV and IV/B pigs, respectively; highest activities were measured in liver and kidney equivalent to 1,076 and 486 ng FB₁, and/or metabolites per g tissue, respectively. Based on plasma and excretion data, systemic bioavailability following IG dosing was estimated to be a very limited 3-4%. Tissue residue levels following IG dosing were 10-20-fold less than IV dosing.