Synthesis of Methyldopa
IUPAC Name of Methyldopa
α-methyl-3-hydroxy-L-tyrosine(S)-2-amino-3-(3,4-dihydroxyphenyl)-2-methyl-propanoic acid.
Merck Synthesis of L-Methyldopa
4-hydroxy 3-methoxy phenylacetone reacts with ammonium chloride and potassium cyanide yields the corresponding racemic mixture of α- aminonitrile. The L-isomer is separated by camphorsulphonic acid salt followed by concentrated sulphuric acid gives the official product methyldopa.Properties of Methyldopa
1. Methyldopa appears as colourless crystals or white to yellowish-white fine powder and it is present in sesquihydrate form.2. Molecular weight is 211.21 g/mol.
3. Melting point is 300°C.
4. Methyldopa is soluble in water, Isopropanol, ethanol, it is hydroscopic in nature and decomposed by oxidizing agents.
5. Absorption from the gastrointestinal tract is variable but averages approximately 50%.
6. Methyldopa is extensively metabolized. Approximately 70 percent of the drug which is absorbed is excreted in the urine as methyldopa and their conjugates.
7. Methyldopa is a potent antihypertensive agent and Antihypertensive effect develops over 4–6 hours and lasts for 12–24 hours.
Therapeutic Uses of Methyldopa
Methyldopa, sold under the brand name Aldomet.The drug used for the treatment of-
1. High blood pressure
2. Gestational hypertension (i.e. Pregnancy induced hypertension)
3. Pre-eclampsia
4. Renal Impairment (i.e. kidney's inability to perform its job)
5. Hypertensive Crisis (B.P. ≥ 180/110).