| 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 | |
A.Colour reactions | 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
|
B.Spectrometry | 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 |
C.pH | 5,5 to 7,5 (1 % w/v solution in previously neutralised mixture of 20 parts dimethylformamide and 80 parts of water) |
D.Specific rotation | [α]D 20 = + 250o to + 295o (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 |