[Code of Federal Regulations]
[Title 9, Volume 1]
[Revised as of January 1, 2001]
From the U.S. Government Printing Office via GPO Access
[CITE: 9CFR113.35]

[Page 569]
 
                  TITLE 9--ANIMALS AND ANIMAL PRODUCTS
 
  CHAPTER I--ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF 
                               AGRICULTURE
 
PART 113--STANDARD REQUIREMENTS--Table of Contents
 
Sec. 113.35  Detection of viricidal activity.

    The test for detection of viricidal activity provided in this 
section shall be conducted when such a test is prescribed in an 
applicable standard requirement or in the filed Outline of Production 
for each inactivated liquid biological product used as diluent for a 
desiccated live virus vaccine in a combination package.
    (a) Bulk or final container samples of completed product from each 
serial shall be tested.
    (b) The product shall be tested with each virus fraction for which 
it is to be used as a diluent. If the vaccine to be rehydrated contains 
more than one virus fraction, the test shall be conducted with each 
fraction after neutralization of the other fraction(s), and/or dilution 
of the vaccine beyond the titer range of the other fraction(s), or the 
test shall be conducted using representative single-fraction desiccated 
vaccines which are prepared by the licensee and which are licensed. 
Provided, That the Administrator may authorize licensees to prepare and 
use unlicensed single-fraction vaccines for this purpose.
    (c) Test procedure: (1) Rehydrate at least two vials of the vaccine 
with the liquid product under test according to label recommendations 
and pool the contents.
    (2) Rehydrate at least two vials of the vaccine with the same volume 
of sterile purified water and pool the contents.
    (3) Neutralize to remove other fractions, if necessary.
    (4) Hold the two pools of vaccine at room temperature (20  deg.to 25 
 deg.C) for 2 hours. The holding period shall begin when rehydration is 
completed.
    (5) Titrate the virus(es) in each pool of vaccine as provided in the 
filed Outline of Production or an applicable standard requirement.
    (6) Compare respective titers.
    (d) If the titer of the vaccine virus(es) rehydrated with the 
product under test is more than 0.7 log10 below the titer of 
the vaccine virus(es) rehydrated with sterile purified water, the 
product is unsatisfactory for use as diluent.
    (e) If the product is unsatisfactory in the first test, one retest 
to rule out faulty techniques may be conducted using four vials of the 
vaccine for each pool and the acceptability of the product judged by the 
results of the second test.
    (f) Liquid products found to be unsatisfactory for use as diluent by 
this test are not prohibited from release as separate licensed products 
if labeled as prescribed in Sec. 112.7(g).

[44 FR 25412, May 1, 1979, as amended at 56 FR 66784, Dec. 26, 1991; 64 
FR 43044, Aug. 9, 1999]