Packaging and storage—
Preserve in single-dose containers,preferably of Type Iglass.
Labeling—
The label states the potassium content in terms of milliequivalents in a given volume,and states also the elemental phosphorus content in terms of millimoles in a given volume.Label the Injection to indicate that it is to be diluted to appropriate strength with water or other suitable fluid prior to administration,and that once opened any unused portion is to be discarded.The label states also the total osmolar concentration in mOsmol per liter.Where the contents are less than 100mL,or where the label states that the Injection is not for direct injection but is to be diluted before use,the label alternatively may state the total osmolar concentration in mOsmol per mL.
Identification—
It responds to the tests for Potassium á191ñand for Phosphate á191ñ.
Assay for monobasic potassium phosphate—
Transfer an accurately measured volume of Injection,equivalent to about 300mg of monobasic potassium phosphate,to a 100-mLbeaker,and dilute with water to about 50mL.Place the electrodes of a suitable pHmeter in the solution,and titrate with 0.1Nsodium hydroxide VSto the inflection point to a pHof about 9.1.Each mLof 0.1Nsodium hydroxide is equivalent to 13.61mg of KH2PO4.
Assay for dibasic potassium phosphate—
Transfer an accurately measured volume of Injection,equivalent to about 300mg of dibasic potassium phosphate,to a 100-mLbeaker,and dilute with water to about 50mL.Place the electrodes of a suitable pHmeter in the solution,and titrate with 0.1Nhydrochloric acid VSto the inflection point to a pHof about 4.2.Each mLof 0.1Nhydrochloric acid is equivalent to 17.42mg of K2HPO4.