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Study Information
Study Attribute Value
CEBS Accession Number: 002-02418-0001-0000-8
Chemical Name: Methdilazine hydrochloride
CASRN: 1229-35-2
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 645558_SCE
Study Result: Negative

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

Trial #: 1    Activation: No Activation    Date: 07/26/1982    Trial Call: Questionable   
  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 1048 394 0.376 7.88 26.0 9.037
Medium 
0         
 50 1047 361 0.345 7.22 26.0 0.000
Test Chemical Methdilazine hydrochloride 
1         
 50 1048 397 0.379 7.94 26.0 9.867 
2         
 50 1041 434 0.417 8.68 26.0 20.915 
5         
 50 1046 420 0.402 8.40 26.0 16.455 
10         
 50 1049 393 0.375 7.86 26.0 8.657
Positive Control Mitomycin-C 
 0.005     
 50 1041 1499 1.440 29.98 26.0 317.629
Mitomycin-C 
 0.01      
 50 1045 2078 1.989 41.56 26.0 476.725
Trend: 1.322        
Probability: 0.093        

Trial #: 2    Activation: No Activation    Date: 07/27/1982    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 351 0.336 7.02 26.0 -0.385
Medium 
0         
 50 1039 350 0.337 7.00 26.0 0.000
Test Chemical Methdilazine hydrochloride 
 0.05      
 50 1048 392 0.374 7.84 26.0 11.038 
 0.16      
 50 1044 389 0.373 7.78 26.0 10.611 
 0.5       
 50 1046 384 0.367 7.68 26.0 8.980 
1.6       
 50 1045 413 0.395 8.26 26.0 17.322 
5         
 50 1045 387 0.370 7.74 26.0 9.937 
16         
 0 0 0 0.000 0.00 26.0 N/A
Positive Control Mitomycin-C 
 0.005     
 50 1049 1487 1.418 29.74 26.0 320.807
Mitomycin-C 
 0.01      
 50 1054 2338 2.218 46.76 26.0 558.493
Trend: 1.431        
Probability: 0.076        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 07/25/1982    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 Medium 
0         
 50 1047 505 0.482 10.10 26.0 0.000
Negative (Not Specified) 
0         
 50 1051 492 0.468 9.84 26.0 -2.945
Test Chemical Methdilazine hydrochloride 
 0.05      
 50 1047 461 0.440 9.22 26.0 -8.713 
 0.16      
 50 1047 495 0.473 9.90 26.0 -1.980 
 0.5       
 50 1047 488 0.466 9.76 26.0 -3.366 
1.6       
 50 1051 437 0.416 8.74 26.0 -13.795 
5         
 50 1046 428 0.409 8.56 26.0 -15.166 
16         
 50 1046 458 0.438 9.16 26.0 -9.220 
50         
 0 0 0 0.000 0.00 0.0 N/A
Positive Control Cyclophosphamide 
2         
 50 1046 2609 2.494 52.18 26.0 417.128
Trend: -2.312        
Probability: 0.990        

Trial #: 2_S9    Activation: Induced Rat Liver S9    Date: 07/27/1982    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 Medium 
0         
 50 1051 408 0.388 8.16 26.0 0.000
Negative (Not Specified) 
0         
 50 1049 415 0.396 8.30 26.0 1.910
Test Chemical Methdilazine hydrochloride 
5         
 50 1046 412 0.394 8.24 26.0 1.463 
10         
 50 1046 428 0.409 8.56 26.0 5.403 
20         
 50 1051 402 0.382 8.04 26.0 -1.471 
30         
 50 1049 403 0.384 8.06 26.0 -1.037 
50         
 0 0 0 0.000 0.00 26.0 N/A
Positive Control Cyclophosphamide 
2         
 50 1051 2638 2.510 52.76 26.0 546.569
Trend: -0.313        
Probability: 0.623