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Study Information
Study Attribute Value
CEBS Accession Number: 002-02122-0001-0000-0
Chemical Name: Erythromycin stearate
CASRN: 643-22-1
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 756378_SCE
Study Result: Negative

Study Result: Negative
Activation Trial Trial Call
No Activation  1  Negative 
No Activation  2  Negative 
Induced Rat Liver S9  1_S9  Negative 
Induced Rat Liver S9  2_S9  Negative 

Trial #: 1    Activation: No Activation    Date: 06/26/1984    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Negative (Not Specified) 
0         
 50 1046 476 0.455 9.52 26.0 3.397
Dimethyl Sulfoxide 
0         
 50 1052 463 0.440 9.26 26.0 0.000
Test Chemical Erythromycin stearate 
5         
 50 1050 462 0.440 9.24 26.0 -0.026 
16         
 31 650 278 0.428 8.97 26.0 -2.822 
50         
 50 1046 483 0.462 9.66 26.0 4.918 
160         
 50 1047 472 0.451 9.44 26.0 2.431 
500         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Mitomycin-C 
 0.0E-4    
 50 1049 853 0.813 17.06 26.0 84.760
Mitomycin-C 
 0.01      
 10 209 619 2.962 61.90 26.0 572.944
Trend: 0.659        
Probability: 0.255        

Trial #: 2    Activation: No Activation    Date: 07/31/1984    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1041 425 0.408 8.50 26.5 0.000
Test Chemical Erythromycin stearate 
25         
 50 1029 377 0.366 7.54 26.5 -10.260 
50         
 50 1027 425 0.414 8.50 26.5 1.363 
100         
 50 1016 396 0.390 7.92 26.5 -4.531 
160         
 0 0 0 0.000 0.00 31.5 N/A
Positive Control Mitomycin-C 
 0.0E-4    
 50 1044 557 0.534 11.14 26.5 30.682
Mitomycin-C 
 0.01      
 10 210 490 2.333 49.00 26.5 471.529
Trend: -0.064        
Probability: 0.525        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 07/10/1984    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1050 418 0.398 8.36 27.0 0.000
Negative (Not Specified) 
0         
 50 1052 417 0.396 8.34 27.0 -0.429
Test Chemical Erythromycin stearate 
50         
 50 1050 374 0.356 7.48 27.0 -10.526 
160         
 50 1050 426 0.406 8.52 27.0 1.914 
500         
 50 1051 449 0.427 8.98 27.0 7.314
Positive Control Cyclophosphamide 
 0.3       
 50 1052 765 0.727 15.30 27.0 82.666
Cyclophosphamide 
2         
 10 210 493 2.348 49.30 27.0 489.713
Trend: 1.576        
Probability: 0.058        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 07/31/1984    Trial Call: Negative   
  Dose
µg/mL		 Number
Cells
Examined		 Number
Chromosomes
Examined		 Total
Number
SCEs		 SCE /
Chromosome		 SCE /
Cell		 Hours in
BRDU		 % Increase
Over Solvent
Control
Vehicle Control Dimethyl Sulfoxide 
0         
 50 1042 467 0.448 9.34 26.0 0.000
Test Chemical Erythromycin stearate 
300         
 50 1049 450 0.429 9.00 26.0 -4.283 
400         
 50 1050 440 0.419 8.80 26.0 -6.499 
500         
 50 1050 475 0.452 9.50 26.0 0.938
Positive Control Cyclophosphamide 
 0.3       
 50 1048 643 0.614 12.86 26.0 36.899
Cyclophosphamide 
2         
 10 210 356 1.695 35.60 26.0 278.252
Trend: -0.018        
Probability: 0.507