8(3(3 



DESCRIPTIONS OP^ ANTIBIOTICS 



citrate buffer, pH 5.0). Active fractions extracted 

 with chloroform at alkaline pH, concentrated, 

 and resubjected to countercurrent distribution. 

 Active fractions crystallized from ethyl ether- 

 petroleum ether to give the complex (27). Compo- 

 nents separated by (a) countercurrent distribution 

 between an aromatic hydrocarbon {e.g., benzene) 

 or a chlorinated solvent (dichloroethane) and a 

 phosphate buffer (pH 6 to 7). The aqueous phase 

 of the active fractions adjusted to pH 9 to 10, and 

 the benzene layer separated and distilled off in 

 vacuo. Spiramycins II and III are cr>'stallized from 

 benzene; (b) chromatography on alumina. To ob- 

 tain spiramycin I, column washed with benzene 

 to elute II and III, then I eluted with benzene- 

 acetone, benzene -ethanol, ethanol, or acetone. 

 Spiramycins II and III are separated by elution 

 of III from the alumina column with cyclohexane- 

 benzene or cyclohexane-ether. II is then eluted 

 with ether or ether-acetone; (c) fractional crys- 

 tallization from benzene (20). 



Chemical and physical properties: Macrolide 

 antibiotics (16). Basic substances (19). Complex: 

 Cream-colored amorphous substance with a bitter 

 taste. Soluble in chloroform, chlorinated solvents, 

 alcohols, hexane, benzene, ketones, ethyl and amyl 

 acetate. Negative Sakaguchi, Molisch, ninhydrin 

 (before and after hydrolysis), Fehling, biuret, and 

 maltol (before and after hydrolysis) tests. Violet- 

 pink in sulfuric or hydrochloric acids. [aYo = 

 — 72° (c = 2 per cent in ethanol). Ultraviolet ab- 

 sorption spectrum maximum at 231 niju (£'^0111 340) . 

 Contains three or four components (depending on 

 producer). Spiramycins II and III differ only by 

 the esterification of the hydroxyl group of I by 

 acetic and propionic acid, respectively (4, 12, 16). 

 Spiramycin I: m.p. 133-137°C. Solubility same as 

 that of complex. Ultraviolet absorption spectrum 

 maximum at 232 niju (£'ilm 322). Infrared absorp- 

 tion spectrum given in references 12 and 19. [afo 

 = —96° (c = 1 per cent in methanol); —57° (c = 

 1 per cent in CHCI3). Rf = 0.04 on paper chroma- 

 tography (paper impregnated with Na2HP04 

 buffer at pH 9.0; with the light phase of cyclo- 

 hexane -methyl isobutyl ketone -water, 85:15:25, 

 as developer). pK,, = 7.7. C = 60.8%; H = 8.7%; 

 O = 28.5%; N = 3.1%. C45H78O15N2 (12, 16, 19, 

 20). Spiramycin II: m.p. 130-133°C. Same solubil- 

 ity as I. Ultraviolet absorption spectrum maxi- 

 mum at 232 m^ (jE'i'cm 307). Infrared spectrum 

 given in reference 12. [aji" = —80° (c = 1 per cent 

 in methanol). pKb = 7.6. C = 60.7%; H = 9.0%; 

 O = 26.8%;; N = 3.1%. Rf = 0.15 (same system as 

 for I). C47HS0O16N2 (16, 19, 20). Spiramycin III: 

 m.p. 128-131°C. Same solubility as I. Ultraviolet 



absorption spectrum maximum at 232 m/j. (£'^0111 

 327). Infrared spectrum given in reference 12. 

 [a]n" = —85° (c = 1 per cent in methanol). pK|, = 

 7.6. Rf = 0.22 (see system under I). C = 61.0%; 

 H = 8.5%; O = 26.7%; N = 3.0%. C48H8,Oi6N2 

 (16, 19). Foromacidin D: Colorless powder; m.p. 

 135-140°C. Ultraviolet absorption spectrum maxi- 

 mum at 231 niyu (log e = 4.44). Infrared absorp- 

 tion spectrum given in reference 13. [ajn = —75° 

 (c = 0.81 per cent in ethanol). C = 59.85%; H = 

 8.48%; N = 3.35% (13). Spiramycins lo.se biologi- 

 cal activity on acid hydrolysis. Products include 

 a- and /3-mycarose (dimethyl-4,6 trihydroxy-2,4,5 

 tetrahydropyran), also isolated from carbomycin, 

 and neospiramycins I, II, and III. N eospiramycin 

 I: m.p. 119-120°C. [a]f = -57° (c = 1 per cent in 

 methanol). CssHeeOieNi . N eospiramycin II: m.p. 

 116-119°C. [«][," = —56° (c = 1 per cent in meth- 

 anol). C40H68O13N2 . Xeospiromycin III: m.p. 117- 

 118°C. Ml" = -52° (c = 1 per cent in methanol). 

 C41H70O13N2 (16). The neospiramycins, on further 

 acid hydrolysis, give rise to the "forocidins" (13, 

 17, 18). Forocidin A: CsoHmOhN. Forocidin B: 

 m.p. 236-238°C. C32H33O12N. Forocidin C: m.p. 

 218-220°C. C33H65O12N. Neospiramycin hydrolysis 

 also yields dimethylamino-5-methyl-6-hydroxy-2- 

 tetrahydropyran (17, 18), the formula of which is 

 given in Chapter 6. Both the neospiramycins and 

 forocidins have an ultraviolet absorption spec- 

 trum maximum at 232 ni/i (16, 17). Like the spira- 

 mycins and the neospiramycins, the forocidins 

 differ in the esterification of the hydroxyl group of 

 A with acetic acid (B) and propionic acid (C) (18). 

 On further hydrolysis, the forocidins give rise to 

 mycaminose (dimethylamino-4 -methyl -6-trihy- 

 dro.xy-2,3,5 tetrahydropyran), which has also 

 been isolated from carbomycin (18). 



Biological activity: Complex: Active on gram- 

 positive bacteria. Slight to no activity on myco- 

 bacteria, gram-negative bacteria, and fungi (4, 6, 

 12, 13). Most active at alkaline pH. Less active in 

 vitro than carbomycin or erythromycin, but 

 equally active in vivo (8). Partial cross-resistance 

 with picromycin, carbomycin, and erythromycin 

 (4, 13), but this is not always found clinically (15). 

 In vivo: Active on infections (mice) caused by 

 Diplococcns, Streptococcus, Staphylococcus, D. 

 pneumoniae, Pasteurella, and Borrelia (4, 6, 12, 13). 

 Active on psittacosis, Rickettsia orientalis (11, 22), 

 and other rickettsiae (rabbits) (2). Antitoxoplas- 

 mic activity in rabbits (3, 5). Active on Plasmo- 

 dium berghei (9) and Endamoeba histolytica in mice 

 (13). Inactive (mice) on trypanosomes (9). Spira- 

 mycins I, II, and III do not differ markedly in 

 their activity' (15). Spiramycin activity in vivo is 



