Title: Cycloserine
CAS Registry Number: 68-41-7
CAS Name: D-4-Amino-3-isoxazolidinone
Additional Names: D-4-amino-3-isoxazolidone; orientomycin
Manufacturers' Codes: PA-94; 106-7
Trademarks: Closina; Farmiserina (Farmitalia); Micoserina; Oxamycin (Merck & Co.); Seromycin (Lilly)
Molecular Formula: C3H6N2O2
Molecular Weight: 102.09
Percent Composition: C 35.29%, H 5.92%, N 27.44%, O 31.34%
Literature References: Antibiotic substance produced by Streptomyces garyphalus sive orchidaceus: Kuehl, Jr., et al., J. Am. Chem. Soc. 77, 2344 (1955); Hidy et al., ibid. 2345; Shull, Sardinas, Antibiot. Chemother. 5, 398 (1955); Shull et al., US 2773878 (1956 to Pfizer); Harned, US 2789983 (1957 to Commercial Solvents); GB 768007 (1957 to Commercial Solvents), C.A. 51, 10847e (1957); US 3124590 (1964 to Commercial Solvents); Howe, US 2845433 (1958 to Merck & Co.). Synthesis: Stammer et al., J. Am. Chem. Soc. 77, 2346 (1955); Peck, US 2772280 (1956 to Merck & Co.); Plattner et al., Helv. Chim. Acta 40, 1531 (1957); Holly, Stammer, US 2840565 (1958 to Merck & Co.). Prepn of crystalline calcium and magnesium salts: Harris et al., US 2832788 (1958 to Merck & Co.). HPLC determn in plasma and urine: D. G. Musson et al., J. Chromatogr. 414, 121 (1987). Comprehensive description: J. W. Lamb, Anal. Profiles Drug Subs. 1, 53-64 (1972); H. A. El-Obeid, A. A. Al-Badr, ibid. 18, 567-597 (1989).
Properties: Crystals, decomp 155-156°. [a]D23 +116° (c = 1.17); [a]25546 +137° (c = 5 in 2N NaOH). uv max: 226 nm (E1%1cm 402). Sol in water, slightly sol in methanol, propylene glycol. Aq solns have a pH around 6. Forms salts with acids and bases. Neutral or acid solns are unstable. Aq solns buffered to pH 10 with sodium carbonate can be stored without loss for one week at refrigerator temps.
Optical Rotation: [a]D23 +116° (c = 1.17); [a]25546 +137° (c = 5 in 2N NaOH)
Absorption maximum: uv max: 226 nm (E1%1cm 402)
Therap-Cat: Antibacterial (tuberculostatic).
Keywords: Antibacterial (Antibiotics); Antibacterial (Tuberculostatic).
Cyclosporins Cyclotheonamides Cyclothiazide Cyclovalone Cycothiamin(e)

Cycloserine ball-and-stick.png
Systematic (IUPAC) name
Clinical data
Trade names Seromycin
AHFS/ monograph
Pregnancy cat. C
Legal status  ?
Pharmacokinetic data
Bioavailability ~70% to 90%
Metabolism Hepatic
Half-life 10 hrs (normal renal function)
Excretion Renal
CAS number 68-41-7 YesY
ATC code J04AB01
PubChem CID 6234
DrugBank DB00260
ChemSpider 5998 YesY
KEGG D00877 YesY
ChEBI CHEBI:40009 YesY
NIAID ChemDB 007654
Chemical data
Formula C3H6N2O2 
Mol. mass 102.092 g/mol
 YesY (what is this?)  (verify)

Cycloserine (4-amino-3-isoxazolidinone) is a drug sold under the brand name Seromycin. It is an antibiotic effective against Mycobacterium tuberculosis. Since the discovery that cycloserine is able to penetrate into the central nervous system, numerous studies have been conducted to assess the efficacy of cycloserine for psychiatric disorders. It has been found to be effective in the treatment of some neurological disorders, due to its effect as a selective partial agonist of the N-methyl-D-aspartic acid (NMDA) glutamatergic receptors found in the basolateral nucleus of the amygdala. Specifically, cycloserine affects the glycine-binding sites which are important for opening these NMDA channels.[1][2] Cycloserine is stable under basic conditions, with the greatest stability at pH = 11.5.[3] Under mildly acidic conditions, ite breaks down into hydroxylamine and D-serine, whereas under prolonged hydrolysis, it breaks down into hydroxylamine and DL-serine.[3][4]