STUDIES CONCERNING THE RESORPTION PROPERT IES OF A LOW-MOLECULAR HUMIC SUBSTANCE AFTER SINGLE ORAL APPLICATION TO RATS

By labeling HS 1500 with a radioactive C-14, it was proofen that after oral application and under certain circumstances, low amounts of low molecular humic acids are for a short time absorbed from the gastroint estinal tract. But the biological availibility of the substance is ver y low (less than 0.1 % of the applied high doses). The plasma concentr ation curve assumes a first order kinetic for invasion and excretion. After oral application of 500 mg/kg b.w. HS 1500 the half life period was 1.5 hours and maximum plasma concentration was 3 mu g/ml. The resu lt obtained indicate that HS 1500 is toxicological riskless after oral administration. Taking into account the pharmacokinetic data, residue s of the substance in animal tissues can be ruled out with high signif icance.