IgG-Coated Red Cells— Red cells coated with human immunoglobulin (IgG). The reagent must be obtained from manufacturers or suppliers licensed by the Center for Biologics Evaluation and Research, Food and Drug Administration. The use of reagents from an unlicensed manufacturer or supplier may invalidate the results.
[Note—There are many manufacturers and suppliers of these reagents that are licensed by the Center for Biologics Evaluation and Research, Food and Drug Administration. Some examples of licensed manufacturers or suppliers are the following: Gamma Biologics, Houston, TX; and Ortho Diagnostics, Raritan, NJ. ]

Imidazole, C3H4N2—68.08 [288-32-4]—White to light yellow crystals. Freely soluble in water. Use ACS reagent grade.

Add the following:
Iminodiacetic Acid, C4H7NO4—133.10[ 142-73-4]—Use a suitable grade with a content of NLT 98.0%.2S (USP38)

Indene, C9H8—116.16 [95-13-6]—Colorless liquid.
Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 10-m capillary column coated with a 1-µm layer of methylsilicone; the injection port temperature is maintained at 200; the detector temperature is maintained at 300; the column temperature is maintained at 100 and programmed to rise 10 per minute to 250. The area of the indene peak is not less than 99% of the total peak area.
Refractive index 831: between 1.5749 and 1.5769 at 20.

Indicators —See separate subsection.

Indigo Carmine —Use Indigotindisulfonate Sodium.

Indole (2,3-Benzopyrrole), C8H7N—117.14 [120-72-9]—Use a suitable grade.

Indole-3-carboxylic Acid, C9H7NO2—161.2 [771-50-6]—Use a suitable grade.

Inosine, C10H12N4O5—268.23 [58-63-9]—White, crystalline powder.
Melting point 741: about 90.

Inositol (Hexahydroxycyclohexane), C6H6(OH)6—180.16 [87-89-8]—Fine, white crystals or a white, crystalline powder; stable in air. Its solutions are neutral to litmus. Optically inactive. One g dissolves in 5.7 mL of water. Slightly soluble in alcohol; insoluble in ether and in chloroform. Store in well-closed containers.
Melting range 741: between 223 and 226.
Loss on drying 731— Dry it at 105 for 4 hours: it loses not more than 0.5% of its weight.
Residue on ignition (Reagent test): not more than 0.1%.

Iobenguane Sulfate (m-Iodobenzylguanidine Hemisulfate Salt), C8H10IN3·½H2SO4—324.1—White powder. Freely soluble in methanol.
Assay— When tested by thin-layer chromatography, with the use of plates coated with chromatographic silica gel mixture, a developing system consisting of a mixture of butyl alcohol, water, and acetic acid (60:25:15), and examined under short-wavelength UV light, not more than a single impurity spot of not more than 0.5% is observed.

Iodic Acid, HIO3—175.91 [7782-68-5]—Use ACS reagent grade.

Iodine, I2—253.81 [7553-56-2]—Use ACS reagent grade.

Iodine Monobromide, IBr—206.81 [7789-33-5]—Black, gray, or blue-purple crystals, crystalline needles, or crystalline chunks.
Assay— Place about 100 mL of acetic acid in a 150-mL beaker. Separately dissolve 2 g of potassium iodide in a minimum volume of water, add this solution to the acetic acid, and mix. Transfer about 200 mg of Iodine Monobromide, accurately weighed, to the beaker containing the potassium iodide and acetic acid mixture, and stir to dissolve. Titrate immediately with 0.1 N sodium thiosulfate VS, determining the endpoint potentiometrically (see Titrimetry 541). Perform a blank determination, and make any necessary correction. Each mL of 0.1 N sodium thiosulfate is equivalent to 20.681 mg of IBr. Not less than 97.5% is found.

Iodine Monochloride, ICl—162.36 [7790-99-0]—Use ACS reagent grade.

Iodoethane, C2H5I—155.9 [75-03-6]—Use a suitable grade.

p-Iodonitrotetrazolium Violet, (2-(4-Iodophenyl)-3-(4-nitrophenyl)-5-phenyltetrazolium chloride), C19H13ClIN5O2—505.70—Light yellow powder.
Assay— When tested by thin-layer chromatography, with the use of plates coated with chromatographic silica gel mixture and a developing system consisting of a mixture of amyl alcohol, formic acid, and water (8:1:1), sprayed with 0.1% sodium thiosulfate solution, and examined under short-wavelength UV light, a single spot is exhibited, with trace impurities.
Melting point 741: 240, with decomposition.

Ion-Exchange Resin —An intimate mixture of 4 parts of a strongly acidic cation-exchanger in the hydrogen form (produced by sulfonation of a styrene-divinylbenzene copolymer, representing 8 to 10% divinylbenzene) and 6 parts of a strongly basic anion-exchanger in the hydroxyl form (produced by amination with trimethylamine of a chloromethylated styrene-divinylbenzene copolymer, representing 3 to 5% divinylbenzene).
[Note—A suitable resin is “Amberlite MB-150,” available from Sigma-Aldrich, www.sigma-aldrich.com. ]

Add the following:
Iron (Powder), Fe—55.85[7439-89-6]—Use a suitable grade with a content of NLT 99.9%.2S (USP38)

Iron Wire, Fe—At. Wt. 55.847—Use a suitable grade.

Isoamyl Alcohol —Use Amyl Alcohol.

Isobutyl Acetate, C6H12O2—116.16 [110-19-0]—Clear, colorless liquid. Slightly soluble in water. Miscible with alcohol.
Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 0.25-mm × 30-m capillary column coated with G2. The injection port temperature is maintained at 130; the column temperature is maintained at 30 and programmed to rise 10 per minute to 180 and held there for 10 minutes. The detector temperature is maintained at 300. The area of the main peak is not less than 99% of the total peak area.
Specific gravity 841: between 0.863 and 0.868.
Refractive index 831: between 1.3900 and 1.3920 at 20.

Isobutyl Alcohol (2-Methyl-1-propanol), (CH3)2CHCH2OH—74.12 [78-83-1]—Use ACS reagent grade.

4-Isobutylacetophenone, C12H16O—176—Pale yellow liquid. Soluble in chloroform, in glycerols, in alcohols, in ether, and in fatty oils; insoluble in water. Use a suitable grade.
[Note—A suitable grade is available from TCI America, www.tciamerica.com. ]

N-Isobutylpiperidone, C9H17NO—155.24—Use a suitable grade.

Isoflupredone Acetate (9--Fluoroprednisolone Acetate), C23H29FO6—420.47—Use Isoflupredone Acetate USP.

l-Isoleucine (2S,3S)-2-Amino-3-methylpentanoic Acid, C6H13NO2—131.17[73-32-5]—Use a suitable grade. [Note—A suitable grade is available as catalog number I2752 from www.sigma-aldrich.com. ]

Isomaltotriose (-d-Glucosyl-(1-6)--d-glucosyl-(1-6)--d-glucose), C18H32O16—504.4 [3371-50-4]—White lyophilized powder. Use a suitable grade.

Isonicotinic Acid, C6H5NO2—123.11 [52-22-1]—Use a suitable grade.

Isonicotinic Acid Hydrazide —Use Isoniazid.

Isooctane —See 2,2,4-Trimethylpentane.

Isopropyl Acetate, C5H10O2—102.13 [108-21-4]—Use a suitable grade.

Isopropyl Alcohol (2-Propanol), (CH3)2CHOH—60.10 [67-63-0]—Use ACS reagent grade.
[Note—For use in assays and tests involving UV spectrophotometry, use ACS reagent grade Isopropyl Alcohol Suitable for Use in UV Spectrophotometry. ]

Isopropyl Alcohol, Dehydrated [67-63-0]—Use Isopropyl Alcohol that previously has been dried by being shaken with a suitable molecular sieve capable of adsorbing water, and filtered.

Isopropyl Ether —See Diisopropyl Ether.

Isopropyl Iodide (2-Iodopropane), C3H7I—169.99 [75-30-9]—Use a suitable grade.

Isopropyl Myristate, C17H34O2—270.45 [110-27-0]—Use Isopropyl Myristate (NF monograph). For use as a solvent in sterility test procedures, Isopropyl Myristate conforms to the following additional specification:
pH of water extract— Transfer 100 mL to a 250-mL centrifuge bottle, add 10 mL of twice-distilled water, close the bottle with a suitable closure, and shake vigorously for 60 minutes. Centrifuge the mixture at 1800 rpm for 20 minutes, aspirate the upper (isopropyl myristate) layer, and determine the pH of the residual water layer: the pH is not less than 6.5.
Isopropyl Myristate not conforming to the test for pH of water extract may be rendered suitable for use in sterility test procedures as follows:
Using a 20-mm × 20-cm glass column, add activated alumina, and tamp down to a height of 15 cm. Pass 500 mL of the isopropyl myristate through the column, using a slight positive pressure to maintain an even flow, and use the eluate collected directly in the sterility test procedure.

Isopropyl Salicylate, C6H4OHCOOCH(CH3)2—180.20—Colorless liquid.
Assay— Inject an appropriate specimen into a suitable gas chromatograph (see Chromatography 621) equipped with a flame-ionization detector, helium being used as the carrier gas. The following conditions have been found suitable: a 2-mm × 1.8-m glass column packed with 7% phase G2 on support S1A; the injection port temperature is maintained at 250; the detector temperature is maintained at 310; the column temperature is maintained at 50 and programmed to rise 10 per minute to 250. The area of the main peak is not less than 97% of the total peak area.

Isopropylamine (2-Aminopropane), C3H7NH2—59.11 [75-31-0]—Clear, colorless, flammable liquid. Miscible with water, with alcohol, and with ether.
Assay— Transfer about 0.2 g, accurately weighed, to a suitable container, add 50 mL of water, and mix. Titrate with 0.1 N hydrochloric acid VS, using a mixture of bromocresol green TS and methyl red TS (5:1) as indicator. Each mL of 0.1 N hydrochloric acid is equivalent to 59.11 mg of C3H9N. Not less than 98% is found.
Boiling range (Reagent test)— Not less than 95% distills between 31 and 33.
Refractive index 831: between 1.3743 and 1.3753, at 20.

Isorhamnetin, C16H12O7—316.27 [418-19-3]—Yellow powder.
Melting point: greater than 300.

Isovaleric Acid (3-Methylbutanoic Acid, Isovalerianic Acid, Isopropylacetic Acid), C5H10O2—102.13 [503-74-2]—Use a suitable grade.

Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Reagent Margareth R. C. Marques, Ph.D.
Senior Scientific Liaison
(301) 816-8106 		(HDQ) Headquarters