Potency test.
Potency test. Bulk or final container samples of completed product shall be diluted with physiological saline so that each 0.25 ml contains not more than 1/800th of the dose recommended on the label and shall be tested for potency, using the two-stage test provided in this paragraph.
(1) Vaccinates. Inject each of at least 10 but not more than 12 young adult hamsters, each weighing 50 to 90 grams, with 0.25 ml of the diluted bacterin either subcutaneously or intramuscularly, in accordance with the label recommendations for use.
(2) Controls. Retain at least 10 but not more than 12 additional hamsters from the same group as unvaccinated controls.
(3) Challenge. From 14 to 18 days postvaccination, challenge each of 10 vaccinates and each of 10 controls intraperitoneally with a suspension of virulent Leptospira grippotyphosa organisms, using a dose of 10–10,000 hamster LD50 as determined by titration.
(4) Post-challenge period. Observe the vaccinates and controls for 14 days post-challenge and record all deaths. If eight or more controls die of leptospirosis, the test is valid and the results shall be evaluated according to the following table:
(1) Vaccinates. Inject each of at least 10 but not more than 12 young adult hamsters, each weighing 50 to 90 grams, with 0.25 ml of the diluted bacterin either subcutaneously or intramuscularly, in accordance with the label recommendations for use.
(2) Controls. Retain at least 10 but not more than 12 additional hamsters from the same group as unvaccinated controls.
(3) Challenge. From 14 to 18 days postvaccination, challenge each of 10 vaccinates and each of 10 controls intraperitoneally with a suspension of virulent Leptospira grippotyphosa organisms, using a dose of 10–10,000 hamster LD50 as determined by titration.
(4) Post-challenge period. Observe the vaccinates and controls for 14 days post-challenge and record all deaths. If eight or more controls die of leptospirosis, the test is valid and the results shall be evaluated according to the following table: