(Ph. Eur. 11.6 update)
Action and use
Treatment of iron-deficiency anaemia.
DEFINITION
Iron Dextran Injection is a sterile colloidal solution containing a complex of iron(III) hydroxide with dextrans of weight average molecular weight between 5000 and 7500.
PRODUCTION
Iron Dextran Injection is produced by a method of manufacture designed to provide an iron-dextran complex with appropriate iron absorption characteristics. This may be confirmed for routine control purposes by the use of an appropriate combination of physico-chemical tests, subject to the agreement of the competent authority.
The method of manufacture is validated to demonstrate that, if tested, the injection would comply with the following test.
The injection complies with the requirements stated under Parenteral Preparations and with the following requirements.
Content of iron, Fe
4.75 to 5.25% w/v.
Content of dextrans
17.0 to 23.0% w/v.
CHARACTERISTICS
A dark brown solution.
IDENTIFICATION
A. Add 5M ammonia to 0.2 mL of the injection previously diluted to 5 mL with water. No precipitate is produced.
B. Mix 1 mL with 100 mL of water. To 10 mL of this solution add 0.2 mL of hydrochloric acid, boil for 30 seconds, cool rapidly, add 4 mL of 13.5M ammonia and 10 mL of hydrogen sulfide solution, boil for at least 4 minutes to remove hydrogen sulfide, cool and filter. Boil 5 mL of the filtrate with 5 mL of cupri-tartaric solution R1; the solution remains greenish in colour and no precipitate is produced. Boil a further 5 mL of the filtrate with 0.5 mL of hydrochloric acid for 5 minutes, cool, add 2.5 mL of 5M sodium hydroxide and 5 mL of cupri-tartaric solution R1 and boil again; a reddish precipitate is produced.
C. To 1 mL add 20 mL of water and 5 mL of hydrochloric acid and boil for 5 minutes. Cool, add an excess of 13.5M ammonia and filter. Wash the precipitate with water, dissolve in the minimum volume of 2M hydrochloric acid and add sufficient water to produce 20 mL. The resulting solution yields reaction B characteristic of iron salts, Appendix VI.
TESTS
Acidity
pH, 5.2 to 6.5, Appendix V L.
Arsenic
To 5.0 mL in a Kjeldahl flask add 10 mL of water and 10 mL of nitric acid and heat until the vigorous evolution of brown fumes ceases. Cool, add 10 mL of sulfuric acid and heat again until fumes are evolved, adding nitric acid dropwise at intervals until oxidation is complete. Cool, add 30 mL of water, bring to the boil and continue boiling until the volume of liquid is reduced to about 20 mL. Cool and dilute to 50 mL with water. Reserve a portion of the solution for the test for Lead. To 5 mL of the solution add 10 mL of water, 15 mL of stannated hydrochloric acid and 3 mL of tin(II) chloride solution AsT. Connect to a condenser and distil 15 mL into 10 mL of water. To the distillate add 0.2 mL of bromine water and remove the excess of bromine with tin(II) chloride solution AsT. The solution complies with the limit test for arsenic, Appendix VII (2 μg per mL).
Copper
To 5.0 mL add 5 mL of nitric acid and heat until the vigorous evolution of brown fumes ceases. Cool, add 2 mL of sulfuric acid and heat again until fumes are evolved, adding nitric acid dropwise at intervals until oxidation is complete. Cool, add 25 mL of hydrochloric acid, warm to dissolve, cool and extract with four 25 mL quantities of isobutyl acetate, discarding the extracts. Evaporate the acid solution to dryness, adding nitric acid dropwise if charring occurs. Dissolve the residue in 10 mL of 1M hydrochloric acid, reserving a portion of the solution for the test for Zinc. To 1 mL add 25 mL of water and 1 g of citric acid, make alkaline to litmus paper with 5M ammonia, dilute to 50 mL with water, add 1 mL of sodium diethyldithiocarbamate solution and allow to stand for 5 minutes. Any colour produced is not more intense than that produced by treating in the same manner a mixture of 3 mL of copper standard solution (10 ppm Cu) and 1 mL of 1M hydrochloric acid beginning at the words ‘add 25 mL of water…’ (60 μg per mL).
Lead
Sample stock solution To 16.0 mL of the solution reserved in the test for Arsenic add 50 mL of hydrochloric acid and wash with four 20 mL quantities of isobutyl acetate, discarding the oraganic layer. Evaporate the acid solution to dryness and dissolve the residue in 20 mL of water.
Use the following solutions:
(1) 12 mL of the sample stock solution.
(2) A mixture of 10 mL of lead standard solution (2 ppm Pb) and 2 mL of sample stock solution.
(3) (Blank solution) A mixture of 10 mL of water and 2 mL of the sample stock solution.
PROCEDURE
To solutions 1, 2 and 3: add 2 mL of buffer solution pH 3.5. Mix and add to 1.2 mL of thioacetamide reagent. Examine through Nessler cylinders after 2 minutes.
SYSTEM SUITABILITY
Solution (2) shows a slight brown colour compared to solution (3).
LIMITS
Any brown colour in solution (1) is not more intense than that in solution (2) (25 μg per mL).
Zinc
To 5.0 mL of the solution reserved in the test for Copper add 15 mL of 1M sodium hydroxide, boil, filter, wash the residue with water and dilute the combined filtrate and washings to 25 mL with water. To 5 mL add 5 mL of 1M hydrochloric acid and 2 g of ammonium chloride, dilute to 50 mL with water, add 1 mL of freshly prepared dilute potassium hexacyanoferrate(II) solution and allow to stand for 20 minutes. Any opalescence produced is not more than that produced when 1 mL of freshly prepared dilute potassium hexacyanoferrate(II) solution is added to a solution prepared from 3 mL of zinc standard solution (25 ppm Zn), 3 mL of 1M sodium hydroxide, 6 mL of 1M hydrochloric acid and 2 g of ammonium chloride diluted to 50 mL with water and allowed to stand for 20 minutes (150 μg per mL).
Chloride
To 5 mL add 75 mL of water and 0.05 mL of nitric acid and titrate immediately with 0.1M silver nitrate VS determining the end point potentiometrically. 6.8 to 9.6 mL of 0.1M silver nitrate VS is required.
Bacterial endotoxins
The endotoxin limit concentration is 0.50 IU per mg of iron, Appendix XIV C.
ASSAY
For iron
To 2 g add 10 mL of water and 5 mL of sulfuric acid and stir for several minutes. Allow to stand for 5 minutes, cool and dilute to 50 mL with water. Prepare a suitable zinc amalgam by covering 300 g of zinc shot with a 2% w/v solution of mercury(II) chloride and stir for 10 minutes. Decant the solution, wash the residue three times with water and transfer it to a column (30 cm × 18 mm) fitted with a sintered-glass disc (ISO 4793, porosity grade 0, is suitable). Activate the zinc amalgam by passing through the column 200 mL of sulfuric acid (5%). Pass the prepared solution slowly through the column and wash successively with 50 mL of water, four 25 mL quantities of sulfuric acid (5%) and 50 mL of water. Titrate the combined eluates with 0.1M ammonium cerium(IV) sulfate VS using ferroin solution as indicator. Each mL of 0.1M ammonium cerium(IV) sulfate VS is equivalent to 5.585 mg of Fe. Determine the weight per mL of the injection, Appendix V G, and calculate the percentage w/v of Fe.
For dextrans
Dilute 1 g to 500 mL with water, dilute 10 mL of the solution to 100 mL with water, transfer 3 mL of the resulting solution to a test tube and cool to 0°. Add, to form a lower layer, 6 mL of a solution prepared and maintained at 0° containing 0.2% w/v of anthrone in a mixture of 19 volumes of sulfuric acid and 1 volume of water, mix and immediately heat on a water bath for 5 minutes. Cool and measure the absorbance of the resulting solution at the maximum at 625 nm, Appendix II B. Repeat the operation using 3 mL of water in place of the dilution of the injection. From the difference between the absorbances calculate the content of glucose present using a calibration curve prepared by treating suitable amounts of D-glucose in the same manner. Each g of D-glucose is equivalent to 0.94 g of dextrans. Determine the weight per mL of the injection, Appendix V G, and calculate the percentage w/v of dextrans.
LABELLING
The strength is stated as the equivalent amount of iron, Fe, in a suitable dose-volume.
