Title: Avoparcin
CAS Registry Number: 37332-99-3
Manufacturers' Codes: AV-290; C-254; CL-81588; LL-AV290
Trademarks: Avotan (Roche)
Literature References: Animal feed glycopeptide antibiotic complex produced by Streptomyces candidus. Prodn: M. P. Kunstmann, J. N. Porter, US 3338786 (1967 to Am. Cyanamid). Fermentation, isoln, characterization: M. P. Kunstmann et al., Antimicrob. Agents Chemother. 8, 242 (1968). Isoln, purif of major components: W. J. McGahren et al., J. Antibiot. 36, 1671 (1983). HPLC separation of a-, b-avoparcin: F. Sztaricskai et al., ibid. 1691. Structural studies: J. J. Hlavka et al., Tetrahedron Lett. 1974, 175; W. J. McGahren et al., J. Am. Chem. Soc. 101, 2237 (1979). Structure: eidem, ibid. 102, 1671 (1980). Stereochemistry and epimerization: G. A. Ellestad et al., J. Antibiot. 36, 1683 (1983). Relationship between structure, antibacterial activity: S.W. Fesik et al., Mol. Pharmacol. 25, 275 (1984). Effect on resistance patterns in chickens: J. R. Walton, Zentralbl. Veterinaermed. (B) 25, 290 (1978), C.A. 89, 173507 (1978). Prevention of exptly induced necrotic enteritis in chickens: J. F. Prescott, Avian Dis. 23, 1072 (1979). Effect on feedlot performance: R. J. Johnson et al., J. Anim. Sci. 48, 1338 (1979).
Properties: White, hygroscopic, amorphous solid; no definitive mp. uv max: 280 nm in neutral or acidic solns; 300 nm in basic solns. Sol in water, DMF, DMSO. Max stability of aq solns is at pH 4-8. Moderately sol in methanol. LD50 in mice, rats, and chickens: >10000 mg/kg orally (Am. Cyanamid, company literature).
Absorption maximum: uv max: 280 nm in neutral or acidic solns; 300 nm in basic solns
Toxicity data: LD50 in mice, rats, and chickens: >10000 mg/kg orally (Am. Cyanamid, company literature)
Derivative Type: a-Avoparcin
CAS Registry Number: 73957-86-5
Molecular Formula: C89H102ClN9O36
Molecular Weight: 1909.25
Percent Composition: C 55.99%, H 5.38%, Cl 1.86%, N 6.60%, O 30.17%
Properties: [a]D25 -96 ±2° (c = 0.62 in 0.1N HCl). uv max (0.1N HCl): 280 nm (E1%1cm 42.0).
Optical Rotation: [a]D25 -96 ±2° (c = 0.62 in 0.1N HCl)
Absorption maximum: uv max (0.1N HCl): 280 nm (E1%1cm 42.0)
Derivative Type: b-Avoparcin
CAS Registry Number: 73957-87-6
Molecular Formula: C89H101Cl2N9O36
Molecular Weight: 1943.70
Percent Composition: C 55.00%, H 5.24%, Cl 3.65%, N 6.49%, O 29.63%
Properties: [a]D25 -102 ±2° (c = 0.65 in 0.1N HCl). uv max (0.1N HCl): 280 nm (E1%1cm 44.0).
Optical Rotation: [a]D25 -102 ±2° (c = 0.65 in 0.1N HCl)
Absorption maximum: uv max (0.1N HCl): 280 nm (E1%1cm 44.0)
Therap-Cat-Vet: Antibacterial; growth promotant.
Azacitidine Azaconazole Azacosterol Azacyclonol Azafenidin

α-Avoparcin (R=H)
β-Avoparcin (R=Cl)
CAS number 37332-99-3 (α/β mix) YesY, 73957-86-5 (α) YesY, 73957-87-6 (β) YesY
ChemSpider 16736403 (α), 16736404 (β)
Jmol-3D images Image 1
Image 2
Molecular formula C89H102ClN9O36 (α)
C89H101Cl2N9O36 (β)
Molar mass 1909.254 (α)
1943.699 (β)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Avoparcin is a glycopeptide antibiotic that is effective against Gram-positive bacteria. It has been used in agriculture as an additive to livestock feed to promote growth in chickens, pigs, and cattle.[1] It is also used as an aid in the prevention of necrotic enteritis in poultry.[1]

Avoparcin is a mixture of two closely related chemical compounds, known as α-avoparcin and β-avoparcin, which differ by the presence of an additional chlorine atom in β-avoparcin. Avoparcin also shares a chemical similarity with vancomycin. Because of this similarity, there is concern that widespread use of avoparcin in animals may lead to an increased prevalence of vancomycin-resistant strains of bacteria.[2][3][4][5]

Avoparcin was once widely used in Australia and the European Union, but it is currently not permitted in either of these regions.[1][6] It was never approved for use in the United States.[7]