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Study Information
Study Attribute Value
CEBS Accession Number: 002-02690-0001-0000-0
Chemical Name: Phthalic anhydride
CASRN: 85-44-9
NTP Study Type: Genetic Toxicology - Mammalian Cell Cytogenetics
NTP Study ID: 164933_SCE
Study Result: Negative

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

Trial #: 1    Activation: No Activation    Date: 10/21/1981    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         
 100 2098 1012 0.482 10.12 26.0 0.000
Test Chemical Phthalic anhydride 
10         
 50 1047 472 0.451 9.44 26.0 -6.541 
30         
 50 1047 518 0.495 10.36 26.0 2.567 
100         
 50 1051 495 0.471 9.90 26.0 -2.360 
300         
 50 1049 497 0.474 9.94 26.0 -1.779
Positive Control Triethylenemelamine 
 0.015     
 50 1049 1607 1.532 32.14 26.0 217.589
Trend: -0.139        
Probability: 0.555        

Trial #: 1_S9    Activation: Induced Rat Liver S9    Date: 10/21/1981    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 470 0.451 9.40 26.0 0.000
Test Chemical Phthalic anhydride 
10         
 50 1044 459 0.440 9.18 26.0 -2.528 
30         
 50 1048 472 0.450 9.44 26.0 -0.149 
100         
 50 1048 458 0.437 9.16 26.0 -3.111 
300         
 50 1043 501 0.480 10.02 26.0 6.494
Positive Control Cyclophosphamide 
1         
 50 1047 1043 0.996 20.86 26.0 120.855
Trend: 0.840        
Probability: 0.200