Percutaneous absorption and excretion of alachlor in rhesus monkeys

The percutaneous absorption and excretion profile of alachlor were evaluated in rhesus monkeys. A preliminary study demonstrated that an average of 86.7 and 9.7% of the administered dose was recovered in the urine and feces, respectively, following intravenous administration of radiolabeled alachlor to rhesus monkeys. In subsequent studies, diluted and undiluted emulsifiable concentrate (EC) and microencapsulated (ME) formulations of radiolabeled alachlor were applied to a 40-cm2 shaved abdominal area and allowed to remain on the skin for 12 hr. The radioactivity excretion profiles in all animals were comparable. In all cases, approximately 88% of the absorbed dose was eliminated via the urine, primarily within the first 48 hr. Comparison of the amount of radiolabel recovered in the topical studies with that recovered following intravenous administration indicated that an average of 8.5 and 3.7% of the alachlor in the topically applied EC and ME formulations, respectively, was absorbed.