Accessed from 128.83.63.20 by nEwp0rt1 on Mon Nov 28 19:59:40 EST 2011

4668 Sodium / Official Monographs USP 35

• CHLORIDE AND SULFATE, Sulfate 〈221〉 relative humidity known not to influence the results, prior to Sample: Equivalent to 0.1 g of Na2HPO4 performing the test. Acceptance criteria: Shows no more sulfate than corre- Insoluble substances—Dissolve a portion equivalent to 10.0 sponds to 0.2 mL of 0.020 N sulfuric acid (NMT 0.2%) g of NaH2PO4 · H2O in 100 mL of hot water, filter through a • ARSENIC, Method I 〈211〉 tared filtering crucible, wash the insoluble residue with hot Test preparation: Equivalent to 187.5 mg of Na2HPO4 in 35 water, and dry at 105° for 2 hours: the weight of the residue so mL of water obtained does not exceed 20 mg (0.2%). Acceptance criteria: NMT 16 ppm Chloride 〈221〉—A portion equivalent to 1.0 g of NaH2PO4 · • HEAVY METALS 〈231〉 H2O shows no more chloride than corresponds to 0.20 mL of Sample stock solution: Dissolve the equivalent to 2.1 g of 0.020 N hydrochloric acid (0.014%). Na2HPO4 in enough water to make 50 mL. Analysis: Transfer 12 mL of the Sample stock solution to a Sulfate 〈221〉—A portion equivalent to 0.20 g of NaH2PO4 · 50-mL color-comparison tube (Test Preparation). Transfer H2O shows no more sulfate than corresponds to 0.30 mL of 11 mL of the Sample stock solution to a second color- 0.020 N sulfuric acid (0.15%). comparison tube containing 1.0 mL of Standard Lead Solu- Aluminum, calcium, and related elements—A solution tion (Monitor Preparation). Transfer 1.0 mL of Standard Lead containing the equivalent of 1.0 g of NaH2PO4 · H2O in 10 mL Solution and 11 mL of water to a third color-comparison of water does not become turbid when rendered slightly alka- tube (Standard Preparation). Proceed as directed for Proce- line to litmus paper with 6 N ammonium hydroxide. dure, omitting the dilution to 50 mL. Arsenic, Method I 〈211〉—Dissolve a portion equivalent to Acceptance criteria: NMT 20 ppm 0.375 g of NaH2PO4 · H2O in 35 mL of water: the limit is 8 ppm. SPECIFIC TESTS Heavy metals 〈231〉—Dissolve a portion equivalent to 1.0 g of • LOSS ON DRYING 〈731〉: Dry a sample at 130° to constant weight. NaH2PO4 · H2O in 20 mL of water, and add 1 mL of 3 N hydro- Acceptance criteria: See Table 1. chloric acid and water to make 25 mL: the limit is 0.002%. Assay—Dissolve about 2.5 g of Monobasic Sodium Phosphate, accurately weighed, in 10 mL of cold water, add 20 mL of a Table 1 cold, saturated solution of sodium chloride, then add phenol- Hydrate Form Acceptance Criteria phthalein TS, and titrate with 1 N sodium hydroxide VS, keep- Dried NMT 5.0% ing the temperature of the solution between 10° and 15° dur- Monohydrate 10.3%–12.0% ing the entire titration. Perform a blank determination, and make any necessary correction. Each mL of 1 N sodium hydrox- Dihydrate 18.5%–21.5% ide is equivalent to 120.0 mg of NaH2PO4. Heptahydrate 43.0%–50.0% Dodecahydrate 55.0%–64.0%

. ADDITIONAL REQUIREMENTS Sodium Phosphates Injection • PACKAGING AND STORAGE: Preserve in tight containers. • LABELING: Label it to indicate whether it is dried or is the monohydrate, the dihydrate, the heptahydrate, or the » Sodium Phosphates Injection is a sterile solu- dodecahydrate. tion of Monobasic Sodium Phosphate and Diba- sic Sodium Phosphate in Water for Injection. It contains not less than 95.0 percent and not

. more than 105.0 percent of the labeled amounts Monobasic Sodium Phosphate of monobasic sodium phosphate (NaH2PO4 · H2O) and dibasic sodium phosphate (Na2HPO4 · NaH2PO4 · xH2O (anhydrous) 119.98 7H2O). It contains no bacteriostat or other Phosphoric acid, monosodium salt, monohydrate. preservative. Monosodium phosphate monohydrate 137.99 [10049-21-5] . Packaging and storage—Preserve in single-dose containers, Phosphoric acid, monosodium salt, dihydrate. preferably of Type I glass. Monosodium phosphate dihydrate 156.01 [13472-35-0]. Labeling—The label states the sodium content in terms of mil- Anhydrous [7558-80-7]. liequivalents in a given volume, and states also the phosphorus content in terms of millimoles in a given volume. Label the » Monobasic Sodium Phosphate contains one or Injection to indicate that it is to be diluted to appropriate two molecules of water of hydration, or is anhy- strength with water or other suitable fluid prior to administra- drous. It contains not less than 98.0 percent and tion and that once opened any unused portion is to be dis- carded. The label states also the total osmolar concentration in not more than 103.0 percent of NaH2PO4, calcu- mOsmol per L. Where the contents are less than 100 mL, or lated on the anhydrous basis. where the label states that the Injection is not for direct injec- tion but is to be diluted before use, the label alternatively may Packaging and storage—Preserve in well-closed containers. state the total osmolar concentration in mOsmol per mL. Labeling—Label it to indicate whether it is anhydrous or is the monohydrate or the dihydrate. USP Reference standards 〈11〉— Identification—A solution (1 in 20) responds to the tests for USP Endotoxin RS Sodium 〈191〉 and for Phosphate 〈191〉. Identification—It responds to the tests for Sodium 〈191〉 and pH 〈791〉: between 4.1 and 4.5, in a solution containing the for Phosphate 〈191〉. equivalent of 1.0 g of NaH2PO4 · H2O in 20 mL of water. Bacterial endotoxins 〈85〉—It contains not more than 1.10 Water, Method I 〈921〉: less than 2.0% (anhydrous form); be- USP Endotoxin Units per mg of sodium phosphates. tween 10.0% and 15.0% (monohydrate); between 18.0% and Particulate matter 〈788〉: meets the requirements under 26.5% (dihydrate). For the monohydrate, the sample may be small-volume injections. ground to a fine powder in an atmosphere of temperature and

Official from May 1, 2012 Copyright (c) 2011 The United States Pharmacopeial Convention. All rights reserved. Accessed from 128.83.63.20 by nEwp0rt1 on Mon Nov 28 19:59:40 EST 2011

USP 35 Official Monographs / Sodium 4669

Other requirements—It meets the requirements under Injec- water. Titrate the excess base potentiometrically with 0.5 N hy- tions 〈1〉. drochloric acid VS to the first inflection point, at a pH of about Assay for monobasic sodium phosphate—Transfer an accu- 9.2. Record the volume, A, in mL, of 0.5 N hydrochloric acid rately measured volume of Injection, equivalent to about 300 consumed. Continue the titration to the second inflection point, mg of anhydrous monobasic sodium phosphate, to a 100-mL at a pH of about 4.4, and record the total volume, B, in mL, of beaker, and dilute with water to about 50 mL. Place the elec- 0.5 N hydrochloric acid required in the titration. For a blank trodes of a suitable pH meter in the solution, and titrate with determination, transfer 15.0 mL of 0.5 N sodium hydroxide into 0.1 N sodium hydroxide VS to the inflection point to a pH of a 250-mL beaker, add 100 mL of water, and immediately titrate about 8.8. Each mL of 0.1 N sodium hydroxide is equivalent to potentiometrically with 0.5 N hydrochloric acid VS. Record the 13.80 mg of NaH2PO4 · H2O. volume, C, in mL, of 0.5 N hydrochloric acid consumed. Each Assay for dibasic sodium phosphate—Transfer an accu- mL of the volume (C − A) of 0.5 N hydrochloric acid is equiva- rately measured volume of Injection, equivalent to about 300 lent to 69.0 mg of monobasic sodium phosphate (NaH2PO4 · mg of anhydrous dibasic sodium phosphate, to a 100-mL H2O). Each mL of the volume (B − C) of 0.5 N hydrochloric beaker, and dilute with water to about 50 mL. Place the elec- acid is equivalent to 134.0 mg of dibasic sodium phosphate trodes of a suitable pH meter in the solution, and titrate with (Na2HPO4 · 7H2O). 0.1 N hydrochloric acid VS to the inflection point to a pH of about 4.0. Each mL of 0.1 N hydrochloric acid is equivalent to

26.81 mg of Na2HPO4 · 7H2O. . Sodium Polystyrene Sulfonate Benzene, diethenyl-, polymer with ethenylbenzene, sulfonated,

. sodium salt. Sodium Phosphates Oral Solution Divinylbenzene copolymer with styrene, sulfonated, sodium salt. » Sodium Phosphates Oral Solution is a solution » Sodium Polystyrene Sulfonate is a cation-ex- of Dibasic Sodium Phosphate and Monobasic So- change resin prepared in the sodium form. Each dium Phosphate, or Dibasic Sodium Phosphate g exchanges not less than 110 mg and not more and Phosphoric Acid, in Purified Water. It con- than 135 mg of potassium, calculated on the an- tains, in each 100 mL, not less than 16.2 g and hydrous basis. not more than 19.8 g of dibasic sodium phos- Packaging and storage—Preserve in well-closed containers. phate (Na2HPO4 · 7H2O), and not less than 43.2 Labeling—Sodium Polystyrene Sulfonate that is intended for g and not more than 52.8 g of monobasic so- preparing suspensions for oral or rectal administration may be labeled Sodium Polystyrene Sulfonate for Suspension. dium phosphate (NaH2PO4 · H2O). Water, Method I 〈921〉: not more than 10.0%. Packaging and storage—Preserve in tight containers. Limit of ammonium salts—Place 1 g in a 50-mL beaker, add Identification—It responds to the tests for Sodium 〈191〉 and 5 mL of 1 N sodium hydroxide, cover the beaker with a watch for Phosphate 〈191〉. glass having a moistened strip of red litmus paper on the un- Specific gravity 〈841〉: between 1.333 and 1.366. derside, and allow to stand for 15 minutes: the litmus paper pH 〈791〉: between 4.4 and 5.2. shows no blue color. Assay—Pipet 25.0 mL of Oral Solution into a 500-mL volumet- Sodium content— ric flask, dilute with water to volume, and mix. Transfer 25.0 Sodium solution—Dissolve in water an accurately weighed mL of this stock solution to a 250-mL beaker, and add 15.0 mL quantity of sodium chloride to make a solution containing 5.00 of 0.5 N sodium hydroxide and 75 mL of water. Proceed as mg of sodium per mL. directed in the Assay under Sodium Phosphates Rectal Solution, Standard graph—Into four 1-liter flasks pipet, respectively, 0, beginning with “Titrate the excess base.” 1, 2, and 3 mL of Sodium solution. To each flask add 0.1 mL of nitric acid, 0.1 mL of sulfuric acid, and 10 mL of low-sodium, low-potassium, nonionic surfactant solution (1 in 50), dilute with water to volume, and mix. Adjust the scale of a suitable . flame spectrophotometer to a reading of 100 at a wavelength Sodium Phosphates Rectal Solution of 588 nm with the solution containing 15 mg of sodium per L. Determine the instrument readings on the other three solutions, » Sodium Phosphates Rectal Solution is a solution and plot the observed readings, on ruled coordinate paper, as of Dibasic Sodium Phosphate and Monobasic So- the ordinate, and the concentration of sodium, in mg per liter, dium Phosphate, or Dibasic Sodium Phosphate as the abscissa. The line intersects the ordinate at, or below, a and Phosphoric Acid, in Purified Water. It con- scale reading of 25 (“blank reading”). Procedure—Ash the equivalent of 1 g of Sodium Polystyrene tains, in each 100 mL, not less than 5.4 g and Sulfonate, accurately weighed, with a slight excess of sulfuric not more than 6.6 g of dibasic sodium phos- acid. Add 1 mL of nitric acid and a few mL of water to the phate (Na2HPO4 · 7H2O), and not less than 14.4 residue. Warm to dissolve, and transfer with water to a 1-liter g and not more than 17.6 g of monobasic so- volumetric flask, dilute with water to volume, and mix. Pipet 10 mL of this solution into a 100-mL volumetric flask, add 1 mL of dium phosphate (NaH2PO4 · H2O). low-sodium, low-potassium, non-ionic surfactant solution (1 in Packaging and storage—Preserve in tight, single-unit con- 50), dilute with water to volume, and mix. Determine the in- tainers, at controlled room temperature. strument reading concomitantly with the readings obtained for plotting the Standard graph, and determine the sodium concen- Identification—It meets the requirements of the tests for So- tration, in mg per liter, by interpolation from the Standard dium 〈191〉 and for Phosphate 〈191〉. Specific gravity 〈841〉: between 1.112 and 1.136. pH 〈791〉: between 5.0 and 5.8. 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

Official from May 1, 2012 Copyright (c) 2011 The United States Pharmacopeial Convention. All rights reserved.