Packaging and storage— Preserve in tight, single-unit containers, at controlled room temperature.

Identification— It meets the requirements of the tests for Sodium 191 and for Phosphate 191.

Specific gravity 841: between 1.112 and 1.136.

pH 791: between 5.0 and 5.8.

Residual solvents 467: meets the requirements.

Assay— Pipet 5.0 mL of Rectal Solution into a 250-mL beaker, and add 15.0 mL of 0.5 N sodium hydroxide VS and 95 mL of water. Titrate the excess base potentiometrically with 0.5 N hydrochloric acid VS to the first inflection point, at a pH of about 9.2. Record the volume (A), in mL, of 0.5 N hydrochloric acid consumed. Continue the titration to the second inflection point, at a pH of about 4.4, and record the total volume (B), in mL, of 0.5 N hydrochloric acid required in the titration. Each mL of the volume (15.0 A) of 0.5 N hydrochloric acid is equivalent to 69.0 mg of monobasic sodium phosphate (NaH2PO4·H2O). Each mL of the volume (B 15.0) of 0.5 N hydrochloric acid is equivalent to 134.0 mg of dibasic sodium phosphate (Na2HPO4·7H2O).

Expert Committee : (MDGRE05) Monograph Development-Gastrointestinal Renal and Endocrine

USP29–NF24 Page 1989

Phone Number : 1-301-816-8251