NARASIN
Overview
Synonyms
(4s)-4-methylsalinomycin;Narasin A
Functional Class
Veterinary Drug
ANTIMICROBIAL_AGENT
ANTIMICROBIAL_AGENT
Evaluations
Evaluation year: 2012
ADI:0–0.005 mg/kg bw
ADI:
0–0.005 mg/kg bw
Comments:
The 70th Committee meeting considered narasin A to be a suitable marker residue for narasin in animal tissues of cattle, pigs and chickens and recommended temporary MRLs for narasin A in cattle tissues, as the available analytical method was not considered fit for purpose. The 75th Committee recommended full MRLs for narasin of 15 μg/kg for cattle muscle and kidney and 50 μg/kg for liver and fat tissues, determined as narasin A. The 70th Committee had previously established an ADI for narasin of
0–0.005 mg/kg bw, based on the NOAEL of 0.5 mg/kg bw/d from GLP-compliant, 1-year dog oral study and a total safety factor of 100.
MRL Comment:
Full MRLs for cattle: 15 μg/kg (muscle & kidney), 50 μg/kg (liver & fat), as narasin A.
Meeting:
75
Report:
Residues:
Toxicological study
Pivotal Study:
GLP-compliant one-year dog study (Novilla & Bernhard, 1986): 5-month-old Beagles (4/sex/group) were given daily oral doses of mycelial narasin by capsule at 0, 0.5, 1.0 or 2.0 mg narasin activity/kg bw/d for 1 year. An additional group (4/sex) was given 2.0 mg/kg bw/d crystalline narasin by capsule. Compound-related effects included: excessive salivation, leg weakness, decreased appetite, laboured respiration, hypoactivity and recumbency, reduced body weight, transient increases in creatine phosphokinase and AST values, and degenerative and/or regenerative changes in cardiac and skeletal muscles and peripheral nerves. A higher proportion of high-dose dogs showed clinical signs and had lesions than mid-dose dogs. Based on mortality, clinical signs, effects on body weight, clinical chemistry and microscopic findings in skeletal and cardiac muscle and peripheral nerves, the NOAEL was 0.5 mg narasin activity/kg bw/day .
Animal Specie:
Dog
Effect:
Minimal to slight peripheral nerve changes & focal skeletal muscle degeneration
NOAEL:
0.5 mg narasin activity/kg bw/day
Point of departure:
0.5 mg narasin activity/kg bw/day
Evaluation year: 2008
ADI:
0-0.005 mg/kg bw
Comments:
The Committee established an ADI of 0–5 μg/kg body weight
on the basis of a NOAEL of 0.5 mg/kg body weight per day
and a safety factor of 100.
MRL Comment:
Recommended maximum residue limits (MRLs) for Cattle, chicken and Pigs of :
- Fat 50 (μg/kg),
- Kidney 15 (μg/kg),
- Liver 50 (μg/kg),
- Muscle 15 (μg/kg)
Report:
Tox Monograph:
Specification: