U.S. PHARMACOPEIA

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Oxytetracycline and Nystatin Capsules
» Oxytetracycline and Nystatin Capsules contain not less than 90.0 percent and not more than 120.0 percent of the labeled amount of oxytetracycline (C22H24N2O9), and not less than 90.0 percent and not more than 135.0 percent of the labeled amount of USP Nystatin Units.
Packaging and storage— Preserve in tight, light-resistant containers.
Identification— Shake a suitable quantity of Capsule contents with methanol to obtain a solution containing about 1 mg of oxytetracycline per mL, and filter. Using the filtrate as the Test Solution, proceed as directed for Method II under Identification—Tetracyclines 193.
Dissolution 711—
Medium: 0.1 N hydrochloric acid; 900 mL.
Apparatus 1: 100 rpm.
Time: 45 minutes.
Procedure— Determine the amount of oxytetracycline (C22H24N2O9) dissolved from UV absorbances at the wavelength of maximum absorbance at about 353 nm of filtered portions of the solution under test, suitably diluted with Dissolution Medium, if necessary, in comparison with a Standard solution having a known concentration of USP Oxytetracycline RS in the same medium.
Tolerances— Not less than 75% (Q) of the labeled amount of C22H24N2O9 is dissolved in 45 minutes.
Uniformity of dosage units 905: meet the requirements for Weight Variation with respect to oxytetracycline.
Water, Method I 921: not more than 7.5%.
Residual solvents 467: meet the requirements.
(Official January 1, 2007)
Assay for oxytetracycline— Place not less than 5 Capsules in a high-speed glass blender jar containing an accurately measured volume of 0.1 N hydrochloric acid, and blend for 3 to 5 minutes, so that the stock solution so obtained contains not less than 150 µg of oxytetracycline (C22H24N2O9) per mL. Proceed as directed under Antibiotics—Microbial Assays 81, using an accurately measured volume of this stock solution diluted quantitatively and stepwise with water to yield a Test Dilution having a concentration of oxytetracycline assumed to be equal to the median dose level of the Standard.
Assay for nystatin— Proceed as directed for Nystatin under Antibiotics—Microbial Assays 81, blending not less than 5 Capsules for 3 to 5 minutes in a high-speed blender with a sufficient accurately measured volume of dimethylformamide to obtain a solution of convenient concentration. Dilute an accurately measured portion of this solution quantitatively with dimethylformamide to obtain a stock solution containing about 400 USP Nystatin Units per mL. Dilute this stock solution quantitatively with Buffer No. 6 to obtain a Test Dilution having a concentration of nystatin assumed to be equal to the median dose level of the Standard.
Auxiliary Information— Staff Liaison : Brian D. Gilbert, Ph.D., Scientist
Expert Committee : (MDANT05) Monograph Development-Antibiotics
USP29–NF24 Page 1617
Phone Number : 1-301-816-8223