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Accessed from 128.83.63.20 by nEwp0rt1 on Thu Nov 24 01:18:27 EST 2011

3038 Enalaprilat / Official Monographs USP 35

Table 1 Relative Retention Limit Component Time (minutes) (w/w, %) Enalaprilat heat degradation product 0.6 vs enalaprilat 0.5 Enalaprilat 1 vs enalaprilat — Benzyl 1 vs — Benzyl alcohol related unknown impurity 1 1.2 vs benzyl alcohol — Benzoic acid 1.4 vs benzyl alcohol — Benzyl alcohol related unknown impurity 2 1.7 vs benzyl alcohol — Benzaldehyde 2.1 vs benzyl alcohol — Enalapril maleate 4.7 vs enalaprilat 0.25 Enalaprilat related impurity A 5.1 vs enalaprilat 1.0 Any other unspecified individual impurity — 0.10 Total impurities — 2.0

Procedure—Proceed as directed in the Assay. Calculate the the label claim, of enalaprilat (C 18H24N2O5) in the portion of percentage of benzyl alcohol, based on the label claim, in the taken by the formula: volume of Injection taken by the formula: 100(CS / CU)(rU / rS) 100(CS /CU)(rU / rS) in which CS is the concentration, in mg per mL, of USP in which CS is the concentration, in mg per mL, of USP Benzyl Enalaprilat RS in the Standard preparation; CU is the concentra- Alcohol RS in the Standard solution; CU is the concentration, in tion, in mg per mL, of enalaprilat in the Assay preparation, mg per mL, of benzyl alcohol in the Test solution; and rU and rS based on the label claim; and rU and rS are the peak responses are the benzyl alcohol peak responses obtained from the Test obtained from the Assay preparation and the Standard prepara- solution and the Standard solution, respectively: between 75.0% tion, respectively. and 120.0% of the labeled amount is found. Other requirements—It meets the requirements under Injec- tions 〈1〉.

. Assay— Buffer solution—Prepare a solution of 0.05 M monobasic po- tassium phosphate. Adjust with phosphoric acid to a pH of 2.5. Mobile phase—Prepare a filtered and degassed of Buffer solution and acetonitrile (84 : 16). Make adjustments if necessary (see System Suitability under Chromatography 〈621〉).

System suitability preparation—Use the Standard preparation. C3H2ClF5O 184.49 Standard preparation—Dissolve an accurately weighed quan- Ethane, 2-chloro-1-(difluoromethoxy)-1,1,2-trifluoro-, (±)-. tity of USP Enalaprilat RS and USP Benzyl Alcohol RS in Buffer (±)-2-Chloro-1,1,2-trifluoroethyl difluoromethyl ether [13838- solution, and dilute quantitatively, and stepwise if necessar y, 16-9]. with Mobile phase to obtain a solution having a known concen- tration of about 0.1 mg per mL of enalaprilat and 0.72 mg per » Enflurane contains not less than 99.9 per cent mL of benzyl alcohol. and not more than 100.0 per cent of C 3H2ClF5O. Assay preparation—Transfer an accurately measured volume Packaging and storage—Preserve in tight, light-resistant of Injection, equivalent to about 5 mg of enalaprilat, to a 50- containers, and avoid exposure to excessive heat. mL volumetric flask. Dilute with Mobile phase to volume, and mix. USP Reference standards 〈11〉— Chromatographic system (see Chromatography 〈621〉)—The USP Enflurane RS chromatograph is equipped with a 215-nm and 258-nm Identification—The IR absorption spectrum of a thin film of it detector (use 215 nm as the initial wavelength, and switch to exhibits maxima only at the same wavelengths as that of a 258 nm after the elution of enalaprilat and before the elution of similar preparation of USP Enflurane RS . benzyl alcohol) and a 4.6-mm ×15-cm, 5-µm column that con- tains packing L1. The flow rate is about 1.5 mL per minute. The Specific gravity 〈841〉: not less than 1.516 and not more than 1.519. column temperature is maintained at 60 °. Chromatograph the System suitability preparation, and record the peak responses as Refractive index 〈831〉: not less than 1.3020 and not more directed for Procedure: the resolution, R, between benzyl alcohol than 1.3038 at 20 °. and enalaprilat is not less than 3.0; the tailing factor for benzyl Acidity or alkalinity—Shake 20 mL with 20 mL of carbon alcohol and the enalaprilat peaks is not more than 1.5; and the dioxide-free for 3 minutes, and allow the layers to sepa- relative standard deviation for replicate injections is not more rate: the aqueous layer requires not more than 0.10 mL of than 2.0%. 0.010 N sodium hydroxide or not more than 0.60 mL of 0.010 Procedure—Separately inject equal volumes (about 20 mL) of N hydrochloric acid for neutralization, bromocresol purple TS the Standard preparation and the Assay preparation into the being used as the indicator. chromatograph, record the chromatograms, and measure all of Water, Method I 〈921〉: not more than 0.14%. the peak responses. Calculate the quantity, in per centage of Limit of nonvolatile residue—Allow 10.0 mL to evaporate at room temperature in a tared evaporating dish, and dr y the resi- due at 50° for 2 hours: the weight of the residue does not exceed 2 mg. 〈221〉—Shake 25 mL with 25 mL of water for 5 min- utes, and allow the to separate completely. Draw off the

Official from May 1, 2012 Copyright (c) 2011 The Pharmacopeial Convention. All rights reserved. Accessed from 128.83.63.20 by nEwp0rt1 on Thu Nov 24 01:18:27 EST 2011

USP 35 Official Monographs / Endotoxin 3039

water layer, and add to it 1 drop of nitric acid and 5 drops of Indicator. The carrier is made from a material appropriate for silver nitrate TS: any turbidity produced is no greater than that the intended depyrogenation processes to which it will be produced in a solution containing 0.35 mL of 0.020 N hydro- subjected. The endotoxin on a carrier is added at a concen- chloric acid. tration sufficient to allow recover y of a minimum of 1000 Limit of fluoride ions—[NOTE—Use plasticware throughout USP Endotoxin Units/carrier. The Endotoxin Indicator would this test.] allow for accurate indication of at least a 3-log reduction in pH 5.25 buffer—Dissolve 110 g of sodium chloride and 1 g USP Endotoxin Units during depyrogenation process of sodium citrate in 700 mL of water in a 2000-mL volumetric challenges. flask. Cautiously add 150 g of sodium hydroxide, and dissolve IDENTIFICATION with shaking. Cool to room temperature, and, while stirring, • CHARACTERISTICS cautiously add 450 mL of glacial acetic acid to the cooled solu- The endotoxin (lipopolysaccharide) has equivalent character- tion. Cool, add 600 mL of , dilute with water istics to those of the USP Endotoxin RS. to volume, and mix: the pH of this solution is between 5.0 and 5.5. PERFORMANCE TESTS Standard stock solution—Transfer 221 mg of sodium fluoride, • CARRIER: The carrier should be the same as or chemically previously dried at 150 ° for 4 hours, to a 100-mL volumetric similar to the sur face or material used for measuring flask, add about 20 mL of water, and mix to dissolve. Add 1.0 depyrogenation, e.g., glass or stainless steel. If not similar, mL of sodium hydroxide solution (1 in 2500), dilute with water then the carrier and endotoxin combination must be at least to volume, and mix. Each mL of this solution contains 1 mg of as resistant to the depyrogenation process as the sur face or fluoride ions. Store in a tightly closed, plastic container. material being measured. The carrier must be Standard solutions—Dilute portions of the Standard stock so- depyrogenated, or the inherent endotoxin level of the carrier lution quantitatively and stepwise with pH 5.25 buffer to obtain should be determined before the addition of the endotoxin 100-mL solutions having concentrations of 1, 3, 5, and 10 µg to the carrier. per mL. • ENDOXIN RECOVERY TESTS Analysis: Proceed as directed for the relevant technique Test solution—Shake 25 mL with 25 mL of water for 5 min- under Bacterial Endotoxins Test 〈85〉. utes, and allow the liquids to separate completely. T ransfer 5.0 Acceptance criteria: The determined endotoxin concentra- mL of the water layer to a 10-mL volumetric flask, dilute with tion is within a factor of 2 of the labeled endotoxin pH 5.25 buffer to volume, and mix. concentration. Procedure—Concomitantly measure the potential (see Titrime- try 〈541〉), in mV, of the Standard solutions and the Test solution, SPECIFIC TESTS with a pH meter capable of a minimum reproducibility of ±0.2 • PURITY mV, equipped with a glass-sleeved calomel-fluoride specific-ion Absence of assay enhancing substances electrode system. [ NOTE—When taking measurements, immerse Analysis: Proceed as directed in the test for inter fering fac- the electrodes in the solution which has been transferred to a tors in Bacterial Endotoxins Test 〈85〉. 150-mL beaker containing a polytef-coated stirring . Allow Acceptance criteria: The Endotoxin Indicator should con- to stir on a magnetic stirrer having an insulated top until equi- tain no substances (e.g., glucans) that can result in en- librium is attained (1 to 2 minutes), and record the potential. hancement of endotoxin spike recover y. Rinse and dr y the electrodes between measurements, taking Absence of depyrogenation enhancing/inhibiting sub- care to avoid damaging the cr ystal of the specific-ion elec- stances: No substance (e.g., lactose, albumin, polyethylene trode.] Plot the logarithm of the fluoride-ion concentrations, in glycol) should be present as filler for the endotoxin, as this µg per mL, of the Standard solutions versus potential, in mV. can result in enhanced or inhibited depyrogenation effects. From the measured potential of the Test solution and the stan- dard curve, determine the concentration, in µg per mL, of fluo- ADDITIONAL REQUIREMENTS ride ions in the Test solution: not more than 10 µg per mL is • PACKAGING AND STORAGE: Store in the original package under found. conditions recommended on the label, and protect from Assay—Inject a volume of Enflurane of suitable size, but not light, toxic substances, excessive heat, and moisture. The packaging and container materials do not adversely affect more than 30 µL, into a suitable chromatograph (see Gas the performance of the article, when used as directed on the Chromatography under Chromatography 〈621〉) equipped with a thermal conductivity detector. Under typical conditions, the in- labeling. EXPIRATION DATE: The expiration date is determined on the strument contains a 4-mm × 3-m stainless steel column packed • with 20% liquid phase G4 on 60- to 80-mesh S1A, the column basis of stability studies from the date of manufacture, which is the date on which the first determination of Endotoxin is temperature-programmed at about 6 ° per minute from 60 ° Units was made. to 125°, and the injection port temperature is maintained at LABELING: The label states that the article is or may be used about 200°. Dry helium is used as the carrier gas at a flow rate • of about 60 mL per minute. Calculate the per centage purity by as an Endotoxin Indicator. It indicates the concentration in dividing 100 times the area under the Enflurane peak by the USP Endotoxin Units/indicator and the recommended stor- sum of all of the areas in the chromatogram. age conditions. The labeling states the sour ce of the endo- (e.g. species and strain number) and includes instruc- tions for preparation and safe disposal of the indicator. If the carrier is labeled, the label must be either easily removable

. or heat resistant, with no substances that could inter fere Endotoxin Indicator for with the assay. For Endotoxin Indicator vials, the label must include instructions for removal of the stopper from vials Depyrogenation before use. If the stopper is heat resistant and designed to be left in the vial, the maximum processing temperature is DEFINITION stated. An Endotoxin Indicator is an article (challenge vial of endotoxin • DISPOSAL: For destruction or discard, follow instructions rec- or a carrier spiked with endotoxin) designed for use in ommended by the manufacturer, or depyrogenate at 250 ° depyrogenation studies. The endotoxin (a purified lipo- for NLT 120 min. polysaccharide) is validated for use in or on an Endotoxin

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