FOR SOLID PACKAGED IN SINGLE-UNIT CONTAINERS: meets the requirements.

(Official January 1, 2007)

Diluent, Mobile phase, and Chromatographic system— Proceed as directed in the Assay under Dicloxacillin Sodium.

Buffer— Use Buffer No. 1 (see Phosphate Buffers and Other Solutions under Antibiotics—Microbial Assays 81).

Standard preparation— Transfer about 100 mg of USP Dicloxacillin Sodium RS, accurately weighed, to a 100-mL volumetric flask; add 20.0 mL of dimethylformamide, 5.0 mL of alcohol, and 20 mL of Buffer; and stir for 5 minutes with the aid of a magnetic stirrer. Dilute with Buffer to volume, and mix. [NOTE—Use this Standard preparation promptly, or refrigerate and use on the day prepared.]

Assay preparation— Constitute Dicloxacillin Sodium for Oral Suspension as directed in the labeling. Transfer an accurately measured volume of the constituted suspension, freshly mixed and free from air bubbles, equivalent to about 125 mg of dicloxacillin (C16H17Cl2N3O5S), to a 200-mL flask. Add 20.0 mL of dimethylformamide and 5.0 mL of alcohol, and stir for 15 minutes. Add 50.0 mL of Buffer, and stir for an additional 15 minutes. Add another 50.0 mL of Buffer, and stir for a third period of 15 minutes. Centrifuge this mixture for 15 minutes, and filter about 30 mL of the supernatant, discarding the first 5 mL of the filtrate. Use the clear filtrate as the Assay preparation. [NOTE—Use this Assay preparation promptly, or refrigerate and use on the day prepared.]

Procedure— Proceed as directed for Procedure in the Assay under Dicloxacillin Sodium. Calculate the quantity, in mg, of dicloxacillin (C19H17Cl2N3O3S) in each mL of the constituted Dicloxacillin for Oral Suspension taken by the formula: in which V is the volume, in mL, of constituted Dicloxacillin for Oral Suspension taken to prepare the Assay preparation; and the other terms are as defined therein.