Läkemedelsverkets föreskrifter (LVFS 2014:16) om Europafarmakopén

Denna författning träder i kraft samma dag som den kommer från tryckeriet.

Läkemedelsverket

CATARINA ANDERSSON FORSMAN Joakim Brandberg

Bilaga

NOTE ON THE MONOGRAPH

This monograph was corrected in order to include verbatim, the assay of heparin method, in chapter 2.7.5 which appeared in the Ph. Eur. prior to Supplement 8.3. This correction was made as a result of the revision of chapter 2.7.5 in Supplement 8.3 from the clotting method to more specific methods and now describes an assay for anti-factor IIa activity and an assay for antifactor Xa activity which is carried out to determine the ratio of anti-factor Xa activity to anti-factor IIa activity. This ratio is meaningful for the potency determination of heparin as a drug substance but not currently suitable for the determination of heparin in antithrombin III concentrates. The requirements of the monograph are therefore considered as unchanged. The monograph with corrected wording is to be taken into account from 01 January 2015.

Human antithrombin III concentrate

Antithrombinum III humanum densatum

Definition

Sterile, freeze-dried preparation of a plasma glycoprotein fraction that inactivates thrombin in the presence of an excess of heparin. It is obtained from human plasma that complies with the monograph on Human plasma for fractionation (0853). The preparation may contain excipients such as stabilisers. When reconstituted in the volume of solvent stated on the label, the potency is not less than 25 IU of antithrombin III per millilitre.

Production

The method of preparation is designed to maintain functional integrity of antithrombin III. It includes a step or steps that have been shown to remove or to inactivate known agents of infection; if substances are used for inactivation of viruses during production, the subsequent purification procedure must be validated to demonstrate that the concentration of these substances is reduced to a suitable level and any residues are such as not to compromise the safety of the preparation for patients. The specific activity is not less than 3 IU of antithrombin III per milligram of total protein, excluding albumin. The antithrombin III is purified and concentrated. No antimicrobial preservative or antibiotic is added. The antithrombin III concentrate is passed through a bacteria-retentive filter, distributed aseptically into its final, sterile containers and immediately frozen. It is then freeze-dried and the containers are closed under vacuum or in an atmosphere of inert gas. It shall be demonstrated that the manufacturing process yields a product with a consistent fraction of antithrombin III able to bind to heparin. It is evaluated by a suitable analytical procedure which is determined during process development, such as: Heparin-binding fraction. Examine by agarose gel electrophoresis 2 (2.2.31). Prepare a 10 g/L solution of agarose for electrophoresis R contain-

ing 15 IU of heparin R per millilitre in barbital buffer solution pH 8.4 R. Pour 5 mL of this solution onto a glass plate 5 cm square. Cool at 4°C for 30 min. Cut 2 wells 2 mm in diameter 1 cm and 4 cm from the side of the plate and 1 cm from the cathode. Introduce into one well 5 µL of the preparation to be examined, diluted to an activity of about 1 IU of antithrombin III per millilitre. Introduce into the other well 5 µL of a solution of a marker dye such as bromophenol blue R. Allow the electrophoresis to proceed at 4°C, using a constant electric field of 7 V/cm, until the dye reaches the anode. Cut across the agarose gel 1.5 cm from that side of the plate on which the preparation to be examined was applied and remove the larger portion of the gel leaving a band 1.5 cm wide containing the material to be examined. Replace the removed portion with an even layer consisting of 3.5 mL of a 10 g/ L solution of agarose for electrophoresis R in barbital buffer solution pH 8.4 R, containing a rabbit anti-human antithrombin III antiserum at a suitable concentration, previously determined, to give adequate peak heights of at least 1.5 cm. Place the plate with the original gel at the cathode so that a 2nd st nd electrophoretic migration can occur at right angles to the 1 . Allow this 2 electrophoresis to proceed using a constant electric field of 2 V/cm for 16 h. Cover the plates with filter paper and several layers of thick lint soaked in a 9 g/L solution of sodium chloride R and compress for 2 h, renewing the saline several times. Rinse with water R, dry the plates and stain with acid blue 92 solution R. Calculate the fraction of antithrombin III bound to heparin, which is the peak closest to the anode, with respect to the total amount of antithrombin III, by measuring the area defined by the 2 precipitation peaks. The fraction of antithrombin III able to bind to heparin is not less than 60 per cent.

Characters

Appearance: white or almost white, hygroscopic, friable solid or powder. Reconstitute the preparation to be examined as stated on the label immediately before carrying out the identification, tests (except those for solubility, total protein and water) and assay.

Identification

It complies with the limits of the assay.

Tests

Solubility. To a container of the preparation to be examined add the volume of liquid stated on the label at the recommended temperature. The preparation dissolves completely under gentle swirling within 10 min in the volume of the solvent stated on the label, forming a clear or slightly turbid, colourless or almost colourless solution. pH (2.2.3): 6.0 to 7.5. Osmolality (2.2.35): minimum 240 mosmol/kg.

Total protein. If necessary, dilute an accurately measured volume of the reconstituted preparation to obtain a solution containing 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 75 g/L solution of sodium molybdate R and 2 mL of a mixture of 1 volume of nitrogen-free sulfuric acid R and 30 volumes of water R. Shake, centrifuge for 5 min, decant the supernatant and allow the inverted tube to drain on filter paper. Determine the nitrogen in the residue by the method of sulfuric acid digestion (2.5.9) and calculate the amount of protein by multiplying the result by 6.25. Heparin: maximum 0.1 IU of heparin per International Unit of antithrombin III. The anticoagulant activity of heparin is determined in vitro by comparing its ability in given conditions to delay the clotting of recalcified citrated sheep plasma with the same ability of a reference preparation of heparin calibrated in International Units. The International Unit is the activity contained in a stated amount of the International Standard, which consists of a quantity of freeze-dried heparin sodium from pork intestinal mucosa. The equivalence in International Units of the International Standard is stated by the World Health Organization. Heparin sodium BRP is calibrated in International Units by comparison with the International Standard by means of the assay given below. Carry out the assay using one of the following methods for determining the onset of clotting and using tubes and other equipment appropriate to the chosen method: a) direct visual inspection, preferably using indirect illumination and viewing against a matt black background; b) spectrophotometric recording of the change in optical density at a wavelength of approximately 600 nm; c) visual detection of the change in fluidity on manual tilting of the tubes; d) mechanical recording of the change in fluidity on stirring, care being taken to cause the minimum disturbance of the solution during the earliest phase of clotting. It is necessary to validate the method for assay of heparin for each preparation to be examined to allow for interference by antithrombin III.

Assay procedure

The volumes are given as examples and may be adapted to the apparatus used provided that the ratios between the different volumes are respected. Dilute heparin sodium BRP with a 9 g/L solution of sodium chloride R to contain a precisely known number of International Units per millilitre and prepare a similar solution of the preparation to be examined which is expected to have the same activity. Using a 9 g/L solution of sodium chloride R, prepare from each solution a series of dilutions in geometric progression such that the clotting time obtained with the lowest concentration is not less than 1.5 times the blank recalcification time, and that obtained with the highest concentration is such as to give a satisfactory log dose-response curve, as determined in a preliminary test.

Place 12 tubes in a bath of iced water, labelling them in duplicate: T1, T2 and T3 for the dilutions of the preparation to be examined and S1, S2 and S3 for the dilutions of the reference preparation. To each tube add 1.0 mL of thawed plasma substrate R1 and 1.0 mL of the appropriate dilution of the preparation to be examined or the reference preparation. After each addition, mix but do not allow bubbles to form. Treating the tubes in the order S1, S2, S3, T1, T2, T3, transfer each tube to a water-bath at 37°C, allow to equilibrate at 37°C for about 15 min and add to each tube 1 mL of a suitable APTT (Activated Partial Thromboplastin Time) reagent containing phospholipid and a contact activator, at a dilution giving a suitable blank recalcification time not exceeding 60 s. After exactly 2 min add 1 mL of a 3.7 g/L solution of calcium chloride R previously heated to 37°C and record as the clotting time the interval in seconds between this last addition and the onset of clotting determined by the chosen technique. Determine the blank recalcification time at the beginning and at the end of the procedure in a similar manner, using 1 mL of a 9 g/ L solution of sodium chloride R in place of one of the heparin dilutions; the 2 blank values obtained should not differ significantly. Transform the clotting times to logarithms, using the mean value for the duplicate tubes. Repeat the procedure using fresh dilutions and carrying out the incubation in the order T1, T2, T3, S1, S2, S3. Calculate the results by the usual statistical methods (5.3). Carry out not fewer than 3 independent assays. For each such assay prepare fresh solutions of the reference preparation and the preparation to be examined and use another, freshly thawed portion of plasma substrate. Calculate the potency of the preparation to be examined, combining the results of these assays, by the usual statistical methods (5.3). When the variance due to differences between assays is significant at P = 0.01, a combined estimate of potency may be obtained by calculating the non-weighted mean of potency estimates. Water. Determined by a suitable method, such as semi-micro determination of water (2.5.12), loss on drying (2.2.32) or near-infrared spectroscopy (2.2.40), the water content is within the limits approved by the competent authority. Sterility (2.6.1). It complies with the test. Pyrogens (2.6.8) or Bacterial endotoxins (2.6.14). It complies with the test for pyrogens or, preferably and where justified and authorised, with a validated in vitro test such as the bacterial endotoxin test. For the pyrogen test, inject per kilogram of the rabbits mass a volume equivalent to 50 IU of antithrombin III. Where the bacterial endotoxin test is used, the preparation to be examined contains less than 0.1 IU of endotoxin per International Unit of antithrombin III.

1 5 CK Prest kits are suitable.

Assay

Human antithrombin III (2.7.17). The estimated potency is not less than 80 per cent and not more than 120 per cent of the stated potency. The confidence limits (P = 0.95) are not less than 90 per cent and not more than 110 per cent of the estimated potency.

Storage

Protected from light, in an airtight container.

Labelling

The label states: – the number of International Units of antithrombin III in the container; – the name and volume of the liquid to be used for reconstitution; – where applicable, the amount of albumin added as a stabiliser.

Elanders Sverige AB, 2015