Attachment IV - Page 32 
-10- DRAFT 
NOVEMBER 7, 1983 
6. Circular Dlchrolam and Optical Rotatory Dispersion (CD and ORD) 
Comparison of the CD or the ORD spectrum of the material prepared 
by recombinant DNA technology with the corresponding spectrum of the native 
material or the reference preparation may support conformational similarity. 
7 . Other Characterization 
Additional physicochemical characterizations may be appropriate 
for recombinant DNA products incorporating carbohydrates, DNA, lipids, and other 
nonprotein components. 
B. Biological tests for Identity and Potency 
Comparing the recombinant DNA product to the natural product in a 
suitable bloassay will provide additional evidence relating to the identity and 
potency of the recombinant DNA product. 
Various types of bloassay may be used. In vitro assays are usually 
faster, less expensive, and more precise than animal studies, yet adequate testing 
of a biological product before introduction into humans may involve animal studies. 
Most vaccines produced by recombinant DNA techniques should be compared to the 
natural substance with respect to their ability to promote immune responses in 
animals. The extent and frequency of animal testing should be determined on a 
case-by-case basis. 
C. Tests for contaminants 
Reliable and sensitive tests will be needed to assay for trace 
contamination and product related impurities in individual production batches. 
Although physicochemical characterization can ensure a high degree of purity of a 
recombinant product, tests for trace contaminants will rely heavily on biological 
indicator systems. 
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