Editorial Note on Part 113
Editorial Note: Nomenclature changes to part 113 appear at 79 FR 55969, Sept. 18, 2014.

§ 113.454 Clostridium Perfringens Type C Antitoxin. Clostridium Perfringens Type C Antitoxin is a specific antibody product containing antibodies directed against the toxin of *Clostridium perfringens* Type C. Each serial shall be tested as provided in this section. Any serial found unsatisfactory by a prescribed test shall not be released. ( a ) Each serial shall meet the applicable general requirements provided in § 113.450.
( b ) *Potency test.* Bulk or final container samples of completed product from each serial shall be tested using the toxin-neutralization test for Beta Antitoxin provided in this section. Dried products shall be rehydrated according to label directions. ( 1 ) When used in this test, the following words and terms shall mean: ( i ) *International antitoxin unit.* (I.U.) That quantity of Beta Antitoxin which reacts with L0 and L+ doses of Standard Toxin according to their definitions.
( ii ) L 0 dose. The largest quantity of toxin which can be mixed with one unit of Standard Antitoxin and not cause sickness or death in injected mice.
( iii ) L + dose. The smallest quantity of toxin which can be mixed with one unit of Standard Antitoxin and cause death in at least 80 percent of injected mice.
( iv ) *Standard antitoxin.* The Beta Antitoxin preparation which has been standardized as to antitoxin unitage on the basis of the International *Clostridium perfringens* Beta Antitoxin Standard and which is either supplied by or acceptable to Animal and Plant Health Inspection Service. The antitoxin unit value shall be stated on the label.
( v ) *Standard toxin.* The Beta toxin preparation which is supplied by or is acceptable to Animal and Plant Health Inspection Service.
( vi ) *Diluent.* The solution used to make proper dilutions prescribed in this test. Such solution shall be made by dissolving 1 gram of peptone and 0.25 gram of sodium chloride in each 100 ml of distilled water; adjusting the pH to 7.2; autoclaving at 250 °F. for 25 minutes; and storing at 4 °C. until used.
( 2 ) The antitoxin content of the test sample shall be determined as follows: ( i ) Make a dilution of Standard Antitoxin to contain 10 International Units of antitoxin per ml.
( ii ) Make one dilution of Standard Toxin to contain 10 L0 doses per ml and make a second dilution of Standard Toxin to contain 10 L+ doses per ml.
( iii ) Dilute 1 ml of the test sample with 49 ml of diluent and combine 1 ml of this dilution with 1 ml of the Standard Toxin diluted to contain 10 L0 doses.
( iv ) Combine 10 International Units of Standard Antitoxin with 10 L0 doses of diluted Standard Toxin and combine 10 International Units of Standard Antitoxin with 10 L+ doses of diluted Standard Toxin.
( v ) Neutralize all toxin-antitoxin mixtures at room temperature for 1 hour and hold in ice water until injections of mice can be made.
( vi ) Five Swiss white mice, each weighing 16-20 grams, shall be used for each toxin-antitoxin mixture. A dose of 0.2 ml shall be injected intravenously into each mouse. Conclude the test 24 hours post-injection and record all deaths.
( 3 ) *Test Interpretation.* ( i ) If any mice inoculated with the mixture of 10 International Units of Standard Antitoxin and 10 L0 doses of Standard Toxin die, the results of the test are a No Test and shall be repeated: *Provided,* That, if the test is not repeated, the serial shall be declared unsatisfactory.
( ii ) If less than 80 percent of the mice inoculated with the mixture of 10 International Units of Standard Antitoxin and 10 L+ doses of Standard Toxin die, the results of the test are a No Test and shall be repeated: *Provided,* That, if the test is not repeated, the serial shall be declared unsatisfactory.
( iii ) If any mice inoculated with the mixture of Clostridium Perfringens Type C Antitoxin diluted 1:50 and 10 L0 doses of Standard Toxin die, the antitoxin is considered to contain less than 500 International Unit per ml and the serial is unsatisfactory.
[39 FR 16859, May 10, 1974. Redesignated at 39 FR 25463, July 11, 1974. Redesignated at 55 FR 35561, Aug. 31, 1990, as amended at 56 FR 66784, Dec. 26, 1991; 61 FR 51777, Oct. 4, 1996]