Packaging and storage—
Preserve in
Containers for Sterile Solids as described under
Injections 
1
.
Labeling—
Where it is intended for use in preparing injectable dosage forms, the label states that it is sterile or must be subjected to further processing during the preparation of injectable dosage forms.
Constituted solution—
At the time of use, it meets the requirements for
Constituted Solutions under
Injections 1.
pH 791:
between 6.5 and 8.5, in a solution containing 10 mg per mL.
Loss on drying 731—
Dry about 100 mg, accurately weighed, in a capillary-stoppered bottle in vacuum at a pressure not exceeding 5 mm of mercury at 60
for 3 hours: it loses not more than 7.0% of its weight.
Heavy metals, Method II 231:
not more than 0.003%.
Free colistin—
Dissolve 80 mg in 3 mL of water, and add 0.05 mL of silicotungstic acid solution (1 in 10): no immediate precipitate is formed.
Assay—
Assay preparation—
Dissolve a suitable quantity of Colistimethate Sodium, accurately weighed, in 2.0 mL of water, add a sufficient accurately measured volume of Buffer No. 6 to obtain a solution having a convenient concentration.
Procedure—
Proceed as directed for Colistimethate Sodium under
Antibiotics—Microbial Assays 81, using an accurately measured volume of
Assay preparation diluted quantitatively with
Buffer No. 6 to yield a
Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
;)
