188 



DESCRIPTIONS OF ANTIBIOTICS 



4. Packchanian, A. Antibiotics cV: Chemo- 



therapy 6: 084-691, IDoC. 



5. Giolitti, G. et al. (!iorn. iiiicroWiol. ."}: TO- 



SS, 1957. 



6. Ark, P. A. and Thompson, J. B. Plant 



Disease Reptr. 41: 452-454, 1957. 



Anipliotericin A 



Produced by: Streptomyces sp. The same culture 

 produces amphotericin B. 



Method of extraction: Whole culture mixed with 

 an equal volume of isopropanol; pH adjusted to 

 10.5. After removal of the mycelium, solution is 

 concentrated in vacuo, witli formation of a ]ire- 

 cipitate. Precipitate washed with water and ace- 

 tone before drying. This crude concentrate con- 

 tains both amphotericin A and B. Crude material 

 slurried in a 2 per cent (weight per volume) meth- 

 anol solution of calcium chloride. Amphotericin 

 A is dissolved by the methanolic calcium chloride 

 solution and can be precipitated from this solution 

 by the addition of water. Repeating this latter 

 procedure yields crystalline amphotericin A. 



Chemical and physical properties: Conjugated 

 tetraene. Slightly soluble (8 to 40 mg per ml) in 

 methanol, glacial acetic acid, and propylene 

 glycol. Soluble in N,N-dimethylformamide, meth- 

 anol-calcium chloride, and basic methanol to the 

 extent of 90 to 125 mg per ml. Insoluble in water, 

 ethanol, butanol, acetone, ethyl acetate, ether, 

 and benzene. Decomposition above 153°C. [«][, ' = 

 — 9.9° in 0.1 N methyl hydroxide-hydrochloric 

 acid. [a]f'' = +32° in acid dimethylformamide. 

 C = 60.3%; H = 8.4%; N = 1.7%. The ultraviolet 

 light absorption of amphotericin A is charac- 

 teristic of a conjugated tetraene, and is similar to 

 that of rimocidin and nystatin. Amphotericin A is 

 amphoteric and forms a water-soluble sodium salt. 

 Negative FeCls test; positive Alolisch test. Potas- 

 sium permanganate and bromine carljon tetra- 

 chloride solutions decolorized. 



Biological activity: Active in vitro against fungi 

 but not against bacteria. Amphotericin A has a 

 wide spectrum of antifungal activity, being active 

 against both filamentous fungi and yeasts. Active 

 in vivo against experimental C albicans, Histo- 

 plasma capsulatum, and Cryptococcus neoformans 

 infections of mice. Absorbed after oral administra- 

 tion to mice. 



Toxicity: LD50 (mice) 450 mg per kg intraperi- 

 toneally. 



Reference: 1. Steinberg, B. A. ct al . Antil)i- 

 otics Ann. 574-591, 1955-1956. 



Amphotericin B 



Produced by: Streptotnyces nodosus (15). This 

 culture also produces amphotericin A (1). 



Method of extraction: Whole culture mixed with 

 an equal volume of isopropanol; pH adjusted to 

 10.5. After removal of the mycelium, solution is 

 neutralized and concentrated in vacuo, with for- 

 mation of a precipitate. Precipitate washed with 

 water and acetone before drying. This crude con- 

 centrate contains both amphotericin A and B. 

 Crude material slurried in a 2 per cent (weight per 

 volume) methanol solution of calcium chloride. 

 Amphotericin B is not appreciably dis.solved in 

 this solvent. Previously undissolved material ex- 

 tracted with acidified N,N-dimethylformamide. 

 Methanol added to solution. Reaction of the form- 

 amide-methanol solution maintained at pH 5, 

 while water is added, resulting in precipitation of 

 amphotericin B. Repeating the latter procedure 

 yields crystalline amphotericin B (1). 



Chemical and physical properties: Amphoteric 

 conjugated heptaene. Deep yellow prisms (from 

 dimethylformamide). Decomposes at >170°C. 

 Soluble in dimethyl sulfoxide and acetic N,N-di- 

 methylformamide (GO to 80 mg per ml). Slightly 

 soluble (0.2 to 4 mg per ml) in propylene glycol, 

 glacial acetic acid, and N,N-dimethylformamide. 

 Insoluble in water, methanol, ethanol, butanol, 

 acetone, ethyl acetate, ether, benzene, chloroform, 

 pyridine, and alcoholic KOH. X^^^^, 363, 382, 406. 

 Infrared spectrum is given in reference 1. [a]'„ " — 

 -33.6 (in 0.1 N methyl hydroxide-HCl) or +33.3 

 (in acid dimethylformamide). Positive Molisch, 

 KMn(J4 , and Br-CCl4 tests. Negative FeCls test. 

 C46HT3-75NO,s-2n : C = 57.59%; H = 8.0%,; N = 

 1.7%. Neutralization equivalent, 959 (perchloric 

 acid in acetic acid). Possibly contains a lactone 

 group. Hydrogenation product is colorless, bio- 

 logically inactive, tetradecahydroamphotericin B, 

 C46H87NO2 , having an infrared spectrum similar 

 to the parent polyene and which darkens at 160°C 

 but is not decomposed at 250°C. Prolonged acetol- 

 ysis of amphotericin B yields tri- and tetraacetates 

 of an amino desoxyhexose "mycosamine," CeHis- 

 NO4 , which is also obtained from nystatin (see 

 Chapter 6). Amphotericin B forms a ])oorly water- 

 soluble sodium salt (1, 2, 5, 9). 



Biological activity: Active in vitro against fungi 

 but not against bacteria. Amphotericin B is more 

 active against yeasts and yeast -like fungi than 

 against filamentous fungi (1, 16). Active in tissue 

 culture at 0.1 to 1.0 Mg per ml against the patho- 

 genic form of Histoplasma capsulatum. Sporo- 

 trichium schenkii, Cryptococcus neoformans, C. 

 albicans, and Blastomyces dermatitidis (6). Cross- 

 resistance with nystatin but not pimaricin (17). 

 Active in vivo against experimental C. albicans, H. 

 capsulatum, Coccidioides immitis, Cr. neoformans. 



