Synonyms

Pimaricin

Definition

Natamycin is a fungicide of the polyene macrolide group, and is produced by natural strains of Streptomyces natalensis or of Streptococcus lactis

Einecs

231-683-5

Chemical formula

C₃₃H₄₇O₁₃N

Molecular weight

665,74

Assay

Content not less than 95 % on the anhydrous basis

Description

White to creamy-white crystalline powder

Identification

On adding a few crystals of natamycin on a spot plate, to a drop of:

• concentrated hydrochloric acid, a blue colour develops,

• concentrated phosphoric acid, a green colour develops,

which changes into pale red after a few minutes

A 0,0005 % w/v solution in 1 % methanolic acetic acid solution has absorption maxima at about 290 nm, 303 nm and 318 nm, a shoulder at about 280 nm and exhibits minima at about 250 nm, 295,5 nm and 311 nm

5,5 to 7,5 (1 % w/v solution in previously neutralised mixture of 20 parts dimethylformamide and 80 parts of water)

[α]_D²⁰ = + 250^o to + 295^o (a 1 % w/v solution in glacial acetic acid, at 20 ^oC and calculated with reference to the dried material)

Purity

Loss on drying

Not more than 8 % (over P₂O₅, in vacuum at 60 ^oC to constant weight)

Sulphated ash

Not more than 0,5 %

Arsenic

Not more than 3 mg/kg

Lead

Not more than 5 mg/kg

Mercury

Not more than 1 mg/kg

Heavy metals (as Pb)

Not more than 10 mg/kg

Microbiological criteria: total viable count

Not more than 100/g