Synthonics to Begin Clinical Trial of Extended Release T3

Synthonics, Inc., a specialty pharmaceutical company focused on the development of proprietary metal coordinated pharmaceuticals, today announced the approval of the Phase 1 clinical trial of PolyZincLiothyronine (PZL), a novel extended release Liothyronine (LT3) compound for the management of hypothyroidism. Enrollment of healthy volunteers is now underway following authorization of the study by the FDA and the University of Chicago’s Institutional Review Board. The study will be conducted in the Clinical Research Center of the University of Chicago under the leadership of Dr. Alexandra Dumitrescu, the Principal Investigator. The study, which is scheduled to start in mid-February, is designed to demonstrate that the release and absorption of LT3 from ingested PZL capsules can mimic physiological serum triiodothyronine (T3) levels observed in healthy individuals.  Dr. Scott Palmer, an assistant professor at Rush Medical College and the chairman of Synthonics’ scientific advisory board, stated that “a sustained release LT3 product will represent the most significant advance in the treatment of hypothyroidism in over forty years.”

About PZL:  PZL is a proprietary copolymer of zinc and LT3 designed to be released in the intestine over time, reducing or eliminating the peaks in circulating T3 levels produced by existing LT3 formulations.  These peaks in T3 levels are associated with side effects, and depending on their magnitude, may pose health risks.  PZL is designed to reduce these peaks and produce steady, euthyroid-like, T3 levels in the blood of hypothyroid patients.

When administered orally, PZL adheres to the intestinal lining of the small bowel where it creates a gastrointestinal depot of drug product from which T3 molecules gradually break free and are absorbed into the bloodstream.  Pre-clinical proof of principle studies were conducted at Rush University Medical Center under the direction of Dr. Antonio C. Bianco (Thyroid 2018 Nov;28(11):1425-1433. doi: 10.1089/thy.2018.0205).   

About Hypothyroidism:  Hypothyroidism, a chronic condition that affects approximately fifteen million Americans, occurs when the thyroid fails to produce adequate quantities of thyroid hormones.  Patients with hypothyroidism typically take levothyroxine (LT4), a prohormone that the body converts to T3, the active hormone that controls metabolism.  A significant subset of the hypothyroid population, however, fails to respond fully to LT4 administration and continues to suffer from symptoms such as fatigue, lethargy, weight gain and depression. Large population surveys have shown that even patients that are otherwise asymptomatic on LT4 report increased memory and quality of life issues as compared to age-matched control patients.

From a physiological standpoint, administration of LT3 could materially improve subjective and objective health parameters for the population of symptomatic hypothyroid patients. However, the rapid absorption and clearance rates of conventional LT3 products may cause side effects, such as palpitation and tightness of the chest that, along with the lack of long-term safety data, have limited its broader clinical use.  PZL is designed to address those issues and provide steady blood T3 levels like those produced by a healthy thyroid gland. 

About Synthonics:  Synthonics is a specialty pharmaceutical company focused on the discovery and development of metal coordinated pharmaceuticals (“MCPs”).  Metal coordination entails attaching a metal, such as magnesium, zinc or bismuth, to a known drug to improve that drug’s pharmacokinetics, performance and safety.  MCP’s of approved drugs are both patentable as new compositions of matter and eligible for FDA review under 505(b)(2). 

For further information, contact John Tinkham, CEO of Synthonics, at

The National Institute Of Diabetes And Digestive And Kidney Diseases of the National Institutes of Health has provided funding for the clinical trial under Award Number R44DK116396. The content of this press release is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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