Thrombin »Thrombin conforms to the regulations of the FDAconcerning biologics (see Biologics á1041ñ).It is a sterile,freeze-dried powder derived from bovine plasma containing the protein substance prepared from prothrombin through interaction with added thromboplastin in the presence of calcium.It is capable,without the addition of other substances,of causing the clotting of whole blood,plasma,or a solution of fibrinogen.Its potency is determined in U.S.Units in terms of the U.S.Standard Thrombin in a test comparing clotting times of fibrinogen solution. Packaging and storage— Preserve at a temperature between 2and 8.Dispense it in the unopened container in which it was placed by the manufacturer. Expiration date— The expiration date is not more than 3years after date of manufacture. Labeling— Label it to indicate that solutions of Thrombin are to be used within a few hours after preparation and are not to be injected into or otherwise allowed to enter large blood vessels. Auxiliary Information— Staff Liaison:Radhakrishna S Tirumalai,Scientist Expert Committee:(BBP)Blood and Blood Products USP28–NF23Page 1923 Phone Number:1-301-816-8339