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Human Coagulation Factor VII

Category Human blood and blood products (coagulant; antihemorrhagic agent).

          Dried Factor VII Fraction is a freeze-dried plasma protein fraction that contains the single-chain glycoprotein factor VII and may also contain small amounts of the activated form, the two-chain derivative factor VIIa, as well as coagulation factors II, IX and X and protein C and protein. It is obtained from human plasma that complies with the requirements stated under Plasma for Fractionation, p. 193. Heparin,antithrombin and other auxiliary substances such as a stabilizer may be added. No antimicrobial preservative is added.

          The specific activity of the preparation before the addition of any protein stabilizer, is not less than 2 IU of factor VII per mg of protein. The potency of the preparation, reconstituted as stated on the label, is not less than 15 IU of factor VII per ml.

Description White or almost white, pale yellow, green or blue powder or friable solid; hygroscopic.

Strengths available 25 and 60 IU per ml.

Dose Intravenous infusion, as prescribed by the physician.

Additional information Factor VII may be used as replacement therapy in patients with rare genetic deficiencies of factor VII. It has a half-life of only 3 to 5 hours. As a result, it needs to be administered more frequently than other factor concentrates for other factor deficiencies. As an alternative, a new technique is to use continuous infusion of factor VIIa concentrate. Factor VIIa is used to treat serious bleeding episodes and to prevent bleeding associated with surgery in patients with hemophilia A or hemophilia B.

Expiration date When stored under the prescribed condition, the expiration date is not later than 3 years from the date of the last satisfactory test for potency.

Packaging and storage Dried Factor VII Fraction shall be kept in tightly closed containers, protected from light and stored at a temperature of 2º to 8º.

Labelling Complies with the “General Information for Biological Products” p. 177. In addition, the label on the container states (1) the content of factor VII expressed in International Units per container; (2) the maximum content of factor II, factor IX and factor X expressed in International Units per container; (3) the name and volume of solvent to be used to reconstitute the preparation; (4) the name and quantity of any added substances, including where applicable, heparin; (5) the amount of protein per container; (6) that the transmission of infectious agents cannot be totally excluded when medicinal products prepared from human blood or plasma are administered.

Identification

A. Using a suitable range of species-specific antisera, carry out precipitation tests on the preparation to be examined. It is recommended that the tests be carried out using antisera specific to the plasma proteins of each species of domestic animal commonly used in the preparation of materials of biological origin in the country concerned. The preparation is shown to contain proteins of human origin and gives negative results with antisera specific to the plasma proteins of other species.

B. The assay for factor VII activity contributes to the identification of the preparation.

pH 6.5 to 7.5 (Appendix 4.11).

Osmolality Not less than 240 mOsmol/kg (Appendix 4.35).

Activated coagulation factors If the preparation to be examined contains heparin, determine the amount present as described in the test for heparin and neutralize the heparin by addition of protamine sulfate (10 μg of protamine sulfate neutralizes 1 IU of heparin). Prepare 1 in 10 and 1 in 100 dilutions of the reconstitutedpreparation to be examined using tris-chloride buffer pH 7.5. Place a series of polystyrene tubes in a water-bath at 37º and add to each tube 0.1 ml of platelet-poor plasma and 0.1 ml of a suitable dilution of cephalin TS or platelet substitute. Allow to stand for 60 seconds. Add to each tube either 0.1 ml of one of the dilutions or 0.1 ml of the buffer solution (control tube). To each tube, add immediately 0.1 ml of a 0.37 per cent w/v solution of calcium chloride, previously heated to 37º, and measure within 30 minutes of the original dilution the time that elapses between addition of the calcium chloride solution and formation of a clot. For each of the dilutions, the coagulation time is not less than 150 seconds. The test is not valid unless the coagulation time measured for the control tube is 200 to 350 seconds.

Heparin If heparin has been added, the preparation being examined contains not more than the amount of heparin stated on the label and in any case not more than 0.5 IU of heparin per IU of factor VII (Appendix 14.2.1).

Thrombin If the preparation to be examined contains heparin, determine the amount present as described in the test for heparin and neutralize the heparin by addition of protamine sulfate (each 10 μg of protamine sulfate neutralizes 1 IU of heparin). In each of two testtubes, mix equal volumes of the reconstituted preparation and a 0.3 per cent w/v solution of fibrinogen. Keep one of the tubes at 37º for 6 hours and the other at room temperature for 24 hours. In a third tube, mix a volume of the fibrinogen solution with an equal volume of a solution of human thrombin (1 IU per ml) and place the tube in a water-bath at 37º. No coagulation occurs in the tubes containing the preparation to be examined. Coagulation occurs within 30 seconds in the tube containing thrombin.

Factor II Carry out the “Biological Assay of Human Coagulation Factor II” (Appendix 15.1.7). The estimated content is not more than 125 per cent of the stated content. The confidence limits (P = 0.95) are not less than 90 per cent and not more than 111 per cent of the estimated potency.

Factor IX Carry out the “Biological Assay of Human Coagulation Factor IX” (Appendix 15.1.4). The estimated content is not more than 125 per cent of the stated content. The confidence limits (P = 0.95) are not less than 80 per cent and not more than 125 per cent of the estimated potency.

Factor X Carry out the “Biological Assay of Human Coagulation Factor X” (Appendix 15.1.5). The estimated content is not more than 125 per cent of the stated content. The confidence limits (P = 0.95) are not less than 90 per cent and not more than 111 per cent of the estimated potency.

Solubility test Reconstitute the preparation as stated on the label or on the leaflet. It dissolves completely under gentle swirling within 10 minutes, giving a clear or slightly opalescent solution that may be coloured.

Water Not more than 3.0 per cent w/w (Karl Fischer Method, Appendix 4.12), add a suitable volume of anhydrous methanol to the container of the preparation to be examined, shake, allow to stand and carry out the determination on a known volume of the supernatant liquid.

Pyrogens Complies with the “Pyrogen Test” (Appendix 8.2), using a volume of the solution containing not less than 30 IU of Factor VII per kg of the rabbit’s weight.

Sterility Complies with the “Sterility Test” (Appendix 10.1).

Total protein If necessary, dilute an accurately measured volume of the reconstituted preparation with saline TS to obtain a solution expected to contain about 15 mg of protein in 2 ml. To 2.0 ml of the solution in a round-bottomed centrifuge tube add 2 ml of a 7.5 per cent w/v solution of sodium molybdate and 2 ml of a mixture of 1 volume of nitrogen-free sulfuric acid and 30 volumes of water. Shake, centrifuge for 5 minutes, decant the supernatant liquid and allow the inverted tube to drain on filter paper. Using residue thus obtained, carry out the “Determination of Nitrogen (Method II, Appendix 6.7), and calculate the content of protein by multiplying the result by 6.25.

Assay Carry out the “Biological Assay of Human Coagulation Factor VII” (Appendix 15.1.8). The estimated potency is not less than 80 per cent and not more than 125 per cent of the stated potency. The confidence limits (P = 0.95) are not less than 80 per cent and not more than 125 per cent of the estimated potency.