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— Weigh and finely powder not less than 20 Tablets. Transfer an accurately weighed portion of the powder, equivalent to about 500 mg of chloramphenicol, to a 200-mL volumetric flask, add 80 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 the portion of Tablets taken by the formula: in which the terms are as defined therein.