Packaging and storage—
Preserve in single-dose or multiple-dose containers, preferably of Type I or Type II glass.
Identification—
To 1 mL of Injection on a watch glass add 2 drops of ammonium hydroxide: no precipitate is formed. Add 2 mL of hydrochloric acid, mix, and add 2 mL of ammonium hydroxide: a brown precipitate is formed.
Acute toxicity—
Select five mice each weighing between 18 and 25 g, maintained on an adequately balanced diet. Inject a dose of Injection, equivalent to 200 mg of iron per kg of body weight, into a tail vein at a rate not exceeding 0.1 mL per second. Keep the mice under observation for 48 hours after the injection. If none of the mice show outward symptoms of toxicity, the requirements of the test are met. If any of the mice die within the observation period, select four groups of ten mice each weighing between 18 and 25 g. Inject, intravenously, all mice of one group with one of the following doses of Injection: 375, 500, 750, or 1000 mg of iron per kg of body weight. Observe the mice for 7 days, and record the number of deaths in each group. If more than 16 mice die, calculate the LD
50 as directed under
Design and Analysis of Biological Assays 
111
: the LD
50 is not less than 500 mg of iron per kg of body weight.
Absorption from injection site—
Prepare a site over the semitendinosus muscle of one leg of each of two rabbits by clipping the fur and disinfecting the exposed skin. Inject each site with a dose of 0.4 mL per kg of body weight in the following manner. Place the needle in the distal end of the semitendinosus muscle at an angle such as to ensure that the full length of the needle is used, then pass it through the sartorius and vastus medialis muscles. House the rabbits separately. Seven days after the injection, sacrifice the rabbits and dissect the treated legs to examine the muscles: no heavy black deposit of unabsorbed iron compounds is observed, and the tissue is only lightly colored.
Nonvolatile residue—
Using a “to contain” pipet, transfer 1.0 mL onto 3 to 5 g of sand spread in a shallow layer in a stainless steel dish, the dish and sand having been previously dried and weighed. Rinse the pipet, with several small portions of water, onto the sand. Evaporate on a steam bath to dryness, continue the drying in an oven at 105
for 15 hours, and weigh: the weight of the residue for Injection labeled to contain 50 mg of iron per mL is not less than 28.0% and not more than 32.0%, that for Injection labeled to contain 75 mg of iron per mL is not less than 35.0% and not more than 40.0%, and that for Injection labeled to contain 100 mg of iron per mL is not less than 37.0% and not more than 43.0%.
Chloride content—
Using a “to contain” pipet, transfer 10.0 mL of Injection into a 150-mL beaker, rinsing the pipet into the beaker with several small portions of water. Add 50 mL of water and 2 mL of nitric acid, mix, and titrate with 0.1 N silver nitrate VS, determining the endpoint potentiometrically with silver-glass electrodes. Each mL of 0.1 N silver nitrate consumed is equivalent to 3.545 mg of chloride (Cl). The chloride content of Injection labeled to contain 50 mg of iron per mL is not less than 0.48% and not more than 0.68%, and that of Injection labeled to contain either 75 mg or 100 mg of iron per mL is not less than 0.8% and not more than 1.1%.
Other requirements—
It meets the requirements under
Injections 1.
Assay for iron—
Iron stock solution—
Transfer an accurately weighed quantity of about 350 mg of ferrous ammonium sulfate hexahydrate to a 1000-mL volumetric flask, add water to dissolve, dilute with water to volume, and mix to obtain a solution having a concentration of 50 µg of iron per mL.
Calcium chloride solution—
Transfer 2.64 g of calcium chloride dihydrate to a 1000-mL volumetric flask, add 500 mL of water, and swirl to dissolve. Add 5.0 mL of hydrochloric acid, and dilute with water to volume.
Standard preparations—
To separate 100-mL volumetric flasks transfer 2.0, 4.0, 6.0, 8.0, and 10.0 mL, respectively, of Iron stock solution. Dilute each flask with Calcium chloride solution to volume, and mix to obtain Standard preparations having known concentrations of 1.0, 2.0, 3.0, 4.0 and 5.0 µg of iron per mL.
Assay preparation—
Using a “to contain” pipet, transfer an accurately measured volume of Injection, equivalent to about 100 mg of iron, to a 200-mL volumetric flask. Dilute with Calcium chloride solution to volume, and mix. Pipet 2.0 mL of this solution into a 250-mL volumetric flask, dilute with Calcium chloride solution to volume, and mix.
Procedure—
Concomitantly determine the absorbances of the
Standard preparations and the
Assay preparation at the iron emission line of 248.3-nm with a suitable atomic absorption spectrophotometer (see
Spectrophotometry and Light-Scattering 851) equipped with an iron hollow-cathode lamp and an air–acetylene flame, using the
Calcium chloride solution as the blank. Plot the absorbance of each
Standard preparation versus concentration, in µg per mL, of iron, and draw the straight line best fitting the five plotted points. From the graph so obtained, determine the concentration, in µg per mL, of iron in the
Assay preparation. Calculate the quantity, in mg, of iron in each mL of the Injection taken by the formula:
25C / V,
in which
C is the concentration, in µg per mL, of iron in the
Assay preparation; and
V is the volume of Injection taken.
