Packaging and storage—
Preserve in tight, light-resistant containers, at controlled room temperature.
Identification—
To a quantity of Oxytetracycline and Nystatin for Oral Suspension (powder), equivalent to about 50 mg of oxytetracycline, add 50 mL of methanol, shake, and allow the mixture to settle. Using the clear supernatant as the
Test Solution, proceed as directed for
Method II under
Identification—Tetracyclines 
193
.
Uniformity of dosage units 905—
FOR SOLID PACKAGED IN SINGLE-UNIT CONTAINERS:
meets the requirements for Content Uniformity with respect to oxytetracycline and nystatin.
pH 791:
between 4.5 and 7.5, in the suspension constituted as directed in the labeling.
Assay for oxytetracycline—
Constitute Oxytetracycline and Nystatin for Oral Suspension as directed in the labeling. Transfer an accurately measured volume of the suspension so obtained, freshly mixed and free from air bubbles, to a suitable volumetric flask, dilute with 0.1 N hydrochloric acid to volume so that the stock solution so obtained contains not less than 150 µg of oxytetracycline per mL, and mix. Proceed as directed for oxytetracycline under
Antibiotics—Microbial Assays 81, using an accurately measured volume of the stock solution diluted quantitatively and stepwise with water to yield a
Test Dilution having a concentration assumed to be equal to the median dose level of the Standard.
Assay for nystatin—
Constitute Oxytetracycline and Nystatin for Oral Suspension as directed in the labeling. Transfer an accurately measured volume of the suspension so obtained, freshly mixed and free from air bubbles, to a blender jar containing a sufficient, accurately measured volume of dimethylformamide to yield a solution of convenient concentration, and blend at high speed for 3 to 5 minutes. Dilute an accurately measured volume of this solution quantitatively with dimethylformamide to obtain a stock solution containing about 400 USP Nystatin Units per mL. Proceed as directed for nystatin under
Antibiotics—Microbial Assays 81, using an accurately measured volume of this solution diluted quantitatively with
Buffer No. 6 to yield a
Test Dilution having a concentration of nystatin assumed to be equal to the median dose level of the Standard.
