Medium: 0.01 N hydrochloric acid; 900 mL.

Apparatus 1: 100 rpm.

Time: 30 minutes.

Procedure— Determine the amount of C11H12Cl2N2O5 dissolved by employing UV absorption at the wavelength of maximum absorbance at about 278 nm on 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 Chloramphenicol RS in the same Medium.

Tolerances— Not less than 85% (Q) of the labeled amount of C11H12Cl2N2O5 is dissolved in 30 minutes.

(Official January 1, 2007)

Mobile phase and Chromatographic system—Proceed as directed in the Assay under Chloramphenicol.

Standard preparation— Transfer about 25 mg of USP Chloramphenicol RS, accurately weighed, to a 200-mL volumetric flask, add 10 mL of water, and heat on a steam bath until completely dissolved. Cool to room temperature, dilute with Mobile phase to volume, and mix. Filter a portion of this solution through a 0.5-µm or finer porosity filter, and use the clear filtrate as the Standard preparation.

Assay preparation— Transfer an accurately counted number of Chloramphenicol Capsules, equivalent to about 2500 mg of chloramphenicol, to a 1000-mL volumetric flask, add 100 mL of water, and heat on a steam bath until the Capsules have disintegrated. Add 300 mL of water, and heat on a steam bath for 20 minutes, with occasional mixing. Cool to room temperature, dilute with water to volume, and mix. Transfer 5.0 mL of the resulting solution to a 100-mL volumetric flask, dilute with Mobile phase to volume, and mix. Filter a portion of this solution through a 0.5-µm or finer porosity filter, and use the clear filtrate as the Assay preparation.

Procedure— Proceed as directed for Procedure in the Assay under Chloramphenicol. Calculate the quantity, in mg, of C11H12Cl2N2O5 in each Capsule taken by the formula: in which N is the number of Capsules taken, and the other terms are as defined therein.