324 



DESCRIPTIONS OF ANTIBIOTICS 



l)()iling Skellysolve C, cold ether, and cold acetone; 

 re.sidue extracted with boiling ethanol, from which 

 crude nybomycin crystals separate on cooling. 

 Filtered broth successively extracted with n-bu- 

 tanol at pH (i.O, or, after acidification to pH 2.5 

 and filtration, with chloroform. After evaporation 

 to dryness of this extract, crude nybomycin is ob- 

 tained in the same way as from mycelium. Pure 

 nybomycin precipitates from a concentrated HCl 

 solution which has been treated with charcoal, 

 after dilution with 5 to 10 parts water. Recrystal- 

 lization from boiling acetic acid solution by cool- 

 ing, or on addition of water, acetone, or other 

 organic solvents (1). II. Filtered mycelium 

 extracted with boiling dimethylformamide, boiling 

 n-butanol, or water at 120-12()°C under 20 to 25 

 pounds of pressure. Crystalline crude nyl)omycin 

 precipitates from these extracts on cooling, and is 

 washed with a hot acjueous solution of sodium 

 versenate (to remove calcium salt) and hot water; 

 recrystallized from dimethylformamide (2). 



Chemical and physical properties: Weakly basic 

 substance. Exists in two interconvertil)le forms: 

 I. white needles, rods, or rhomboid crystals 

 (crystallized from glacial acetic acid); II. crystal- 

 lized from dimethyl formamide or concentrated 

 HCl-water; characterized by their different in- 

 frared spectra in potassium bromide briquette. 

 Sublimes in vacuo at 250°C with no change of 

 ultraviolet absorption spectrum or l)iological 

 activity. Darkens at about 330°C without melting. 

 Solul)le in concentrated HCl and sulfuric acids, 

 and somewhat soluble in dichloroacetic acid. 

 Recovered from these solvents unchanged on ad- 

 dition of water. Very slightly solulilc in boiling 

 dimethylformamide, boiling water, pyridine, and 

 methyl isobutyl ketone. Insoluble (at 24°C or 

 boiling point ) in 2-propanol, acetonitrile, benzene, 

 chloroform, n-butyl ether, dioxane, ethyl acetate, 

 lower alcohols, water, 1 A^ NaOH, and 1 A' HCl 

 (1,2). Ultraviolet absorption spectrum maxima at 

 266 and 285 m^ (ethanol) (1) or at 222, 266, 286, and 

 369 niM, with inflections at 236, 298, and 355 m^ 

 (a = 61.8, 103.1, 136.2, 41.1, 50.2, 107.7, and 37.4, 

 respectively) in dimethylformamide, methanol, 

 0.01 A^ ethanolic H.2SO4 , or 0.01 A" ethanolic KOH 

 (2). Infrared spectra of Forms I and II given in 

 reference 2. Optically inactive. Negative FeCls , 

 biuret, ninhydrin, ToUen, Benedict, neutral 

 permanganate, Ehrlich (p-dimethylaminobenz- 

 aklehyde), Ehrlich, Pauly, and Br. in CCI4 tests. 

 CsHtO.N or C16HHN.2O4: C = 64.41%; H = 4.87%; 

 N = 9.12%. Molecular weight, 164 (1) or 298 (2). 

 Hydrochloride: Yellow substance Acclatc: White, 

 crystals; m.p. 235-237°C. Ultraviolet absorption 



spectrum same as the base. Dichloroacetate: Crys- 

 talline; m.p. 253-256°C (1, 2). On paper chroma- 

 tography, nybomycin gives a blue fluorescence in 

 neutral and alkaline systems and a yellow fluo- 

 rescence in acid (2). 



Biological activity: Nybomycin and its salts are 

 active on gram-positive bacteria, certain gram- 

 negative l)acteria, certain fungi, and phages. 

 Against bacteria, nybomj'cin and its acetate differ 

 in activity, the base being active against certain 

 gram-positive organisms at 1.5 to 32 /xg per ml and 

 the acetate being active against the same organisms 

 at 0.8 to 8 /xg per ml. The acetate is also active at 

 4 to 15 ixg per ml against a number of bacteria 

 resistant to nybomycin. Both are active against K. 

 pneumoniae (2 fj.g per ml), but not against other 

 gram-negative bacteria. Nybomycin is active 

 against M. tuberculosis H37Rv at 0.5 /xg per ml. 

 Nybomycin acetate, but not nybomycin, is active 

 on .4. niger (6.2 /xg per ml) and Endothia parasitica 

 (12.5 ng per ml). Both are active on Microsponun 

 canis (10 /xg per ml), but not on other fungi tested. 

 Both are active on a variety of phages, including 

 certain staphylophages, coliphages, B. cereus 

 phage. Staph, aureus phage, and S. griseus phage. 

 No obvious correlation between antiphage and 

 antibacterial (antihost) activity. Certain coli- 

 phages are stimulated. Neither nybomycin nor its 

 salts are active inraice on St reptncocc us hemoiyticus , 

 Pasteurella multocida, Sal. typhi, Sal. paratyphi, 

 or M. tuberculosis. Nybomycin, liut not its acetate, 

 gives partial protection against K. pneumoniae 

 (mice). Also inactive on Newcastle disease virus 

 NJ-Kl), vaccinia (eggs), influenza A (PR 8, mice 

 and eggs), and SK poliovirus (mice) (1, 3). 



Toxicity: Nybomycin: LD50 (mice) 650 mg per kg 

 intraperitoneally. Nybomycin acetate: LD50 (mice) 

 200 mg per kg intraperitoneally (3). 



References: 



1. Strelitz, F. et al. Proc. Natl. Acad. Sci, U. 



S. 41:620-624, 1955. 



2. l']V)le, T. E. et al. Antibiotics & Chemo- 



therapy 8:627-630, 1958. 



3. lirock, T. 1). and Sokolski, W. T. Anti- 



biotics & Chemotherapy 8:631-636, 1958. 



Nystatin 



Produced by: Streptomyces noursei (5, 30); this 

 organism also produces cycloheximide (1). Strep- 

 tomyces sp. (40). S. albulus; this strain also pro- 

 duces two forms of cycloheximide and antitumor 

 antibiotic E 73 (37). 



Synonyms: Fungicidin (1). Closely related to 

 antimycoin. 



Method of extraction: I. Mycelium heated at 



