placenta. The plasma half-life is one hour and is not altered appreciably by the thyroid status of the patient. Due to the concentration in the thyroid, however, dosing intervals may last 8 hours or longer. Less than 10% of the drug is excreted unchanged, with the remaining fraction undergoing extensive hepatic metabolism via glucuronidation. Chemical synthesis Propylthiouracil can be prepared from ethyl 3-oxohexanoate and thiourea. Role in taste Propylthiouracil, together with phenylthiocarbamide (PTC), are known to have bitter taste. However, it seems the propensity for tasting these compounds is genetically based and the bitter taste is likely to be engendered by the thiocyanate moiety, also present in PTC. History It was approved by the United States Food and Drug Administration in 1947. References External links Antithyroid drugs Bitter compounds IARC Group 2B carcinogens Pyrimidines Thioureas Wikipedia medicine articles ready to translate Nucleobases