Description
Crystalline T3 (liothyronine sodium, Cytomel) has a rapid onset and short duration of action. It is the
therapy of choice when it is desirable to have rapid onset or cessation of activity, such as in patients with
heart disease.
Chemical Properties
Off-White Solid
Originator
Cytomel,SKF,US,1956
Uses
3,3’,5-Triiodo-L-thyronine (Levothyroxine EP Impurity A) is one of the hormones produced by the thyroid gland that is involved in the maintenance of metabolic homeostasis. Also produced in peripheral tissues as the active metabolite of Thyroxine.
Uses
One of the hormones produced by the thyroid gland that is involved in the maintenance of metabolic homeostasis. Also produced in peripheral tissues as the active metabolite of Thyroxine.
Uses
T3 or 3,3',5-Triiodo-L-thyronine is a thyroid hormone involved with many physiological processes in the human body including growth and development, metabolism, body temperature and heart rate. Free and total T3 serum levels are measured by LC-MS/MS for determination of hyperthyroidism caused by excess T3. This Certified Spiking Solution is suitable for use as a starting material in preparation of linearity standards, calibrators, and controls for thyroid hormone testing methods by LC-MS/MS.
Definition
ChEBI: An iodothyronine compound having iodo substituents at the 3-, 3'- and 5-positions. Although some is produced in the thyroid, most of the 3,3',5-triiodo-L-thyronine in the body is generated by mono-deiodination of L-thyroxi
e in the peripheral tissues. Its metabolic activity is about 3 to 5 times that of L-thyroxine. The sodium salt is used in the treatment of hypothyroidism.
Application
3,3′,5′-Triiodo-L-thyronine (T3) is an endocrine hormone produced by the thyroid gland and is regarded as an active thyroid hormone at cellular level. Thyroxine (T4) serves as a precursor for T3 and is generated in extrathyroidal tissues.
3,3′,5-Triiodo-L-thyronine sodium salt has been used for inducing thyroid hormone manipulations in mice. It has also been used In cell culturing of hippocampal, retinal, proximal tubule and glomerular explant.
Manufacturing Process
The 3,5-diiodo compound used as a starting material is a known material and
may be prepared by the method in British Patents 643,089 and 671,070 and
in the Journal of the Chemical Society, London, 1949, page 3424.
Synthesis: L-diiodo thyronine (1.05 g) is dissolved in ammonia (specific
gravity 0.880) (40 ml) and methanol (40 ml) and iodinated slowly with
shaking with N-iodine in KI solution at room temperature. After iodination,most of the ammonia and methanol are removed by evaporation under
diminished pressure, water is added to the original volume, the solution is
heated to 60°C and brought to pH 4 with hydrochloric acid. A crystalline
precipitate is obtained which after cooling to room temperature is collected
and washed with water. At this stage, the crude triiodo thyronine is
contaminated with thyroxine and a little unchanged diiodo thyronine.
Purification: The crude precipitate is dissolved in boiling 2N HCl (300 ml) and
filtered from the relatively insoluble thyroxine hydrochloride. The hot filtrate is
brought to pH 4 with 5N NaOH and triiodo thyronine again separates; after
chilling at 0° to 4°C it is collected, washed with water and dried. The yield of
triiodo thyronine is 70 to 75% of the theoretical. This triiodo thyronine still
contains some thyroxine (about 10%).
The final purification consists of chromatographic separation of thyroxine and
triiodo thyronine on a kieselguhr column using 20% chloroform in n-butanol
equilibrated with 0.5N NaOH as the developing solvent. 80 to 100 mg triiodo
thyronine is purified during each run on a 50 g kieselguhr column. Pure Ltriiodo thyronine has MP 236° to 237°C (dec.) and [α]D29.5° = +21.5 in a
4.75% solution in a mixture of 1 part of N HCl and 2 parts of ethanol.
Liothyronine is commonly used as the sodium salt.
brand name
Triomet-131 (Abbott);
Tri-Thyrotope (Bristol-Myers Squibb).
Therapeutic Function
Thyroid hormone
Biological Activity
3,3′,5′-Triiodo-L-thyronine (T3) increases the rates of protein synthesis, stimulates the breakdown of cholesterol and effects embryonic development. In cell culture, T3 regulates cell differentiation and protein expression. The interaction of T3 with nonhistone proteins in the chromatin initiates the thyroid hormone activity. Thyroid hormones regulate the differentiation and development of tissues and affect a number of metabolic processes. The level of circulating T3 hormone is reduced in hypothyroidism.
Biochem/physiol Actions
3,3′,5-Triiodo-L-thyronine also referred to as O-(4-Hydroxy-3-iodophenyl)-3,5-diiodo-L-tyrosine or T3 is the biologically active thyroid hormone. In hypothyroidism pateints, triiodothyronine enhances mood and neuropsychological function. The product also positively regulates the hepatic FGF21 expression and stimulates the metabolic breakdown of glucose, fats, and proteins by enhancing the levels of numerous metabolic enzymes such as hexokinase, liver glucose 6-phosphatase as well as mitochondrial enzymes for oxidative phosphorylation. Additionally, the product facilitates the normal body growth in children and is pivotal for central nervous system maturation in foetus.
Purification Methods
Likely impurities are as in thyroxine. Purify it by dissolving in dilute NH3 at ~20o, then crystallise it by addition of dilute acetic acid to pH 6. Alternatively 35g are purified by dissolving it in a mixture of EtOH (250mL) and 2N NaOH (100mL), then hot 2N HCl is added to the boiling solution until the pH is 4-5. After cooling for a few hours, the solid is filtered off and dried in a vacuum [m 233-235o(dec)]. [Chambers et al. J Chem Soc 2433 1949, Beilstein 14 III 1566, 14 IV 2373.]
