Significance of Phosphorus-Nitrogen Ratio in U.S.P. Thyroid

Biologically defective U.S.P. thyroid tablets which have appeared recently on the American market have been prepared from triple strength U.S.P. desiccated thyroid powder supplied by a European distributor. This material, with an unnaturally high iodotyrosine and low iodothyronine content, also has a phosphorus-nitrogen ratio greater than that found in genuine U.S.P. thyroid. Chemical evidence suggests that suboptimally iodinated casein was added to thyroid powder to increase the organic iodine content of the blend. Artificial mixtures have been prepared which closely resemble the physical, chemical, and biological characteristics of known defective U.S.P. thyroid.