USP 35 Official Monographs / Azithromycin 2279 C 38H 72N 2O 12 H 2O

Transcription

1 . USP 35 Official Monographs / Azithromycin 2279 not more than per cent of the labeled amount of azathioprine (C 9 H 7 N 7 O 2 S). Packaging and storage Preserve in Containers for Sterile Solids as described under Injections 1, at controlled room temperature. diffusion currents of the Assay preparation and the Standard preparation, respectively. Azithromycin USP Reference standards 11 USP Azathioprine RS USP Mercaptopurine RS USP Endotoxin RS Completeness of 641 The contents of 1 container are soluble in 10 ml of water, to give a clear, bright yellow, essentially free from foreign matter. Identification The principal spot in the chromatogram of the specimen under examination obtained in the test for Limit of mercaptopurine shows the same R F value as that obtained with the of USP Azathioprine RS. Bacterial endotoxins 85 It contains not more than 1.0 USP Endotoxin Unit per mg of azathioprine. C 38H 72N 2O ph 791 : between 9.8 and 11.0, the contents of 1 container being dissolved in 10 ml of water. C 38H 72N 2O 12 H 2O Water, Method I 921 : not more than 7.0%, the Test Prepa- C 38H 72N 2O 12 2H 2O ration being prepared as directed for a hygroscopic specimen. 1-Oxa-6-azacyclopentadecan-15-one, 13-[(2,6-dideoxy-3-C- Limit of mercaptopurine Prepare s in dimethylmethyl-3-o-methyl-α-l-ribo-hexopyranosyl)oxy]-2-ethylformamide containing, respectively, 10 mg of Azathioprine So- 3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11- dium for Injection per ml, 10 mg of USP Azathioprine RS per [[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl] ml, and 100 µg of USP Mer captopurine RS per ml. Apply 15 oxy]-, [2R(2R*,3S*,4R*,5R*,8R*,10R*,11R*,12S*, µl of the USP Mer captopurine RS and 5- µl portions of 13S*,14R*)]; the other two s at points about 2 cm from the bottom (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-Cedge of a thin-layer chromatographic plate (see Chromatogramethyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl- phy 621 ) coated with a 250- µm layer of microcr ystalline cellu- 3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11- lose. Allow the spots to dr y, and develop the chromatogram in [[3,4,6-trideoxy-3-(dimethylamino)-β-D-xylo-hexopyranosyl] a suitable chamber, using butyl alcohol, previously saturated oxy]-1-oxa-6-azacyclopentadecan-15-one; with 5 N ammonium hydroxide, as the solvent, until the solvent 9-Deoxo-9a-aza-9a-methyl-9a-homoerythromycin A front has moved about 15 cm from the point of application. Anhydrous [ ]. Remove the plate, air-dr y, and locate the spots by viewing Monohydrate [ ]. under short- and long-wavelength UV light: any spot in the Dihydrate [ ]. chromatogram from azathioprine, other than the principal spot, DEFINITION is not more intense than the spot in the chromatogram ob- Azithromycin is anhydrous or contains one or two molecules of tained with USP Mer captopurine RS (3.0%). water of hydration. It contains the equivalent of NL T 945 µg Other requirements It meets the requirements under Injec- and NMT 1030 µg of azithromycin (C 38H 72N 2O 12) per mg, tions 1 and Uniformity of Dosage Units 905. calculated on the anhydrous basis. Assay IDENTIFICATION Standard preparation Transfer 25 mg of USP Azathioprine A. INFRARED ABSORPTION 197K : If a difference appears in RS, accurately weighed, to a 50-mL volumetric flask, dissolve in the IR spectra of the analyte and the standard, dissolve equal 2.5 ml of 0.1 N sodium hydroxide, dilute with water to volportions of the test specimen and the Reference Standard in ume, and mix. Pipet 10.0 ml of this into a 50-mL equal volumes of methanol. Evaporate the s to dr y- volumetric flask, dilute with 0.1 N sulfuric acid to volume, and ness on a water bath, and dr y at 80 for 30 min under mix. vacuum. Perform the test on the residues. Assay preparation Transfer the contents of 1 vial of Azathi- B. The retention time of the azithromycin peak in the Samoprine Sodium for Injection with the aid of water to a 100-mL ple corresponds to that in the Standard, as volumetric flask, dilute with water to volume, and mix. Pipet 10 obtained in the Assay. ml of this into another 100-mL volumetric flask, dilute with 0.1 N sulfuric acid to volume, and mix. ASSAY Procedure Transfer 20 ml each of the Standard preparation PROCEDURE and the Assay preparation, separately, to polarographic cells, and deaerate for 10 minutes with nitrogen that previously has cm.] been saturated with 0.1 N sulfuric acid. Blanket the Mobile phase: Dissolve 5.8 g of monobasic potassium phos- with saturated nitrogen, insert the dropping mer cury electrode phate in 2130 ml of water, and add 870 ml of acetonitrile. of a suitable polarograph, and record the polarogram from Adjust with 6 ml of 10 N potassium hydroxide to a ph of 0.60 volt to 1.00 volt, using a saturated calomel electrode as 11.0 ± 0.1, and filter. the reference electrode. Determine the height of the diffusion Standard stock : mg/ml of USP Azithro- current as the difference between the residual current and diffu- mycin RS in acetonitrile. [ NOTE Sonicate as necessar y.] sion current plateau. Calculate the quantity, in mg, of azathithe Standard stock in Mobile phase Standard : 3.3 µg/ml of USP Azithromycin RS from oprine (C 9H 7N 7O 2S) in the volume of from the vial used for the Assay preparation taken by the formula: Sample stock : mg/ml of Azithromycin in acetonitrile. [NOTE Sonicate as necessar y.] 0.1C(i d) U / (i d) S Sample : 3.3 µg/ml of azithromycin from the Sample stock in Mobile phase in which C is the concentration, in µg per ml, of USP Azathi- stock : 0.16 mg/ml of USP oprine RS in the Standard preparation; and ( i d) U and ( i d) S are the Azaerythromycin A RS in acetonitrile and Mobile phase (1:9).

2 2280 Azithromycin / Official Monographs USP 35 [NOTE Dissolve in acetonitrile, using 10% of the final vol- Diluent: Acetonitrile and Solution A (1:3) ume. Swirl and sonicate to dissolve. Dilute with Mobile phase Standard stock : 45 µg/ml of USP to volume.] Desosaminylazithromycin RS, 105 µg/ml of USP N- : 3.3 µg/ml of azithromycin Demethylazithromycin RS, and 160 µg/ml of USP from the Sample stock and 3.2 µg/ml of azaer ythro- Azithromycin RS in acetonitrile mycin A from the stock in Mobile Standard : 0.9 µg/ml of USP phase Desosaminylazithromycin RS, 2.1 µg/ml of USP N- Demethylazithromycin RS, and 3.2 µg/ml of USP Azithromycin RS from the Standard stock in Diluent Sample : 33 mg of Azithromycin in a 100-mL volumetric flask. Add 5 ml of acetonitrile, and sonicate for Detector type: Dual glassy carbon electrodes about 20 s to dissolve. Dilute with Diluent to volume. Detector mode: Oxidative screen mode [NOTE Use this within 6 h.] Detector settings: Electrode 1 set at ± 0.05 V, elec- trode 2 set at ± 0.05 V, background current opti- mized to 85 ± 15 nanoamperes Column Guard column: 4.6-mm 5-cm; 5- µm packing L29 Detector type: Dual glassy carbon electrodes Analytical column: 4.6-mm 15-cm; 5- µm packing L29 Detector mode: Oxidative screen mode or 3-µm packing L49 without the guard column Detector settings: Electrode 1 set at ± 0.05 V, Flow rate: 1.5 ml/min electrode 2 set at ± 0.05 V, background current Injection size: 50 µl optimized to 95 ± 25 nanoamperes [NOTE In general, maintain electrode 1 at 0.12 V less Samples: Standard and than electrode 2, and maintain the electrodes at a [NOTE The relative retention times for azaer ythromycin A constant temperature of about 26.] and azithromycin with the L29 column are 0.7 and 1.0, Column respectively. The relative retention times for azaer ythromy- Guard column: 4.6-mm 5-cm; 5- µm packing L29 cin A and azithromycin with the L49 column are 0.8 and Analytical column: 4.6-mm 15-cm; 5- µm packing 1.0, respectively.] L29 or 3- µm packing L49 without the guard column. Flow rate: 0.4 ml/min Re: NLT 2.5 between azaer ythromycin A and Injection size: 50 µl azithromycin, Column efficiency: NLT 1000 theoretical plates, Stan- Sample: Standard dard Tailing factor range: for azithromycin, Standard Column efficiency: NLT 1500 theoretical plates for the azithromycin peak Relative standard deviation: NMT 2.0%, Standard Tailing factor: NMT 1.5 for each peak Relative standard deviation: NMT 5% for each of these compounds Samples: Standard and Sample Calculate the quantity, in µg, of C 38H 72N 2O 12 in each mg of Samples: Standard and Sample Azithromycin taken: [NOTE Record the Sample chromatograms for NLT 3.3 times the retention time of the azithromycin Result = (r U/r S) (C S/C U) P peak.] Calculate the percentages of desosaminylazithromycin and r U = peak response from Sample N-demethylazithromycin in the portion of Azithromycin r S = peak response from the Standard taken: C S = concentration of USP Azithromycin RS in the Standard Result = (r U/r S) (C S/C U) F 100 C U = concentration of Azithromycin in the Sample r U = peak area for the relevant analyte from the P = potency of USP Azithromycin RS ( µg/mg of Sample azithromycin) r S = peak area for the relevant analyte from the Acceptance criteria: µg/mg on the anhydrous Standard basis C S = concentration of the appropriate USP Reference Standard in the Standard (µg/ml) IMPURITIES C U = concentration of the Sample (mg/ml) Inorganic Impurities F = unit conversion (0.001 mg/ µg) RESIDUE ON IGNITION 281 : NMT 0.3%, the charred residue Calculate the percentages of other related substances in being moistened with 2 ml of nitric acid and 5 drops of the portion of Azithromycin taken: sulfuric acid HEAVY METALS, Method II 231 : NMT 25 ppm Result = (r U/r S) (C S/C U) F 100 Organic Impurities PROCEDURE 1 [NOTE Use Organic Impurities, Procedure 2 when r U = peak area of each additional impurity from the the impurity profile includes azithromycin related compound Sample F.] r S = peak area of the azithromycin peak from the Standard cm.] C S = concentration of USP Azithromycin RS in the Mobile phase: Proceed as directed in the Assay. Standard (µg/ml) Solution A: 2.7 mg/ml of monobasic potassium phosphate C U = concentration of the Sample (mg/ml) in water. Adjust with 10 N potassium hydroxide to a ph of F = unit conversion (0.001 mg/ µg) 7.5 ± 0.1.

3 USP 35 Official Monographs / Azithromycin 2281 Acceptance criteria: See Impurity Table 1. r U = peak response for each impurity from the Sample Impurity Table 1 r S = peak response of azithromycin from the Standard Relative Acceptance C S = concentration of USP Azithromycin RS in the Retention Criteria, Standard (µg/ml) Name Time NMT (%) C U = nominal concentration of azithromycin in the Desosaminylazithromycin Sample (mg/ml) N-demethylazithromycin F 1 = unit conversion factor (0.001 mg/ µg) F 2 = relative response factor (see Impurity Table 1) Total impurities 3.0 Acceptance criteria: See Impurity Table 2. PROCEDURE 2 [NOTE Use Organic Impurities, Procedure 2 when Impurity Table 2 the impurity profile includes azithromycin related compound Relative F.] Relative Response Acceptance Solution A: 1.8 mg/ml of anhydrous dibasic sodium Retention Factor Criteria, phosphate in water. Adjust with 1 N sodium hydroxide or Name Time (F 2) NMT (%) 10% phosphoric acid to a ph of 8.9. Solution B: Acetonitrile and methanol (3:1) Azithromycin N-oxide a Mobile phase: See the gradient table below. 3 -(N,N-Didemethyl) N-formylazithromycin b Time Solution A Solution B 3 -(N,N-Didemethyl) (min) (%) (%) azithromycin (aminoazithromycin) c Azithromycin related compound F d Desosaminylazithromycin e N Demethylazithromycin f a (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylazinoyl)-β-D b (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O 3,5,6,8,10,12,14-heptamethyl-11-[[3-formamido-3,4,6-trideoxy-β-D-xylohexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. c (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O 3,5,6,8,10,12,14-heptamethyl-11-[[3-amino-3,4,6-trideoxy-β-D-xylohexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. d 3 -N-Demethyl-3 -N-formylazithromycin. e (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-Ethyl-3,4,10,13-tetrahydroxy- 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-D f (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-methylamino-β-D-xylohexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. g (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-α-Lribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14- heptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-d-xylo-hexopyranosyl] oxy]-1-oxa-6-azacyclopentadecan-15-one. h (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3,3-dimethyl-α- L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14- heptamethyl-11-[[3,4,6-trideoxy-3-oxo-β-d-xylo-hexopyranosyl]oxy]-1-oxa- 6-azacyclopentadecan-15-one. i 9-Deoxo-9a-aza-9a-homoerythromycin A. j Specified unidentified impurity. k (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- methyl-α-l-ribo-hexopyranosyl)oxy]-2-propyl-3,4,10-trihydroxy- 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-Dxylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one dihydrate. l (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O 3,5,6,8,10,12,14-heptamethyl-11-[[3-[N-(4-methylphenylsulfonyl)-Nmethylamino]-3,4,6-trideoxy-β-D-xylo-hexopyranosyl]oxy]-1-oxa-6- azacyclopentadecan-15-one. m (2R,3R,4S,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- methyl-α-l-ribo-hexopyranosyl)oxy]-2-ethyl-4,10-dihydroxy- 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D- Solution C: 1.73 mg/ml of monobasic ammonium phosphate. Adjust with ammonia TS to a ph of 10.0 ± Solution D: Methanol, acetonitrile, and Solution C (7:6:7) : mg/ml of USP Azithromycin Related Compound F RS and mg/ml of USP Desosaminylazithromycin RS in Solution D Standard : 86 µg/ml of USP Azithromycin RS in Solution D Sample : 8.6 mg/ml of Azithromycin in Solution D Detector: UV 210 nm Column: 4.6-mm 25-cm; 5- µm packing L1 Column temperature: 60 Flow rate: 1 ml/min Injection size: 50 µl Samples: and Standard Peak-to-valley ratio: NLT 1.4, [NOTE The calculation formula for peak-to-valley ratio is: Result = H P/H V H P = height above the baseline of the desosaminylazithromycin peak H V = height above the baseline of the lowest point of the curve separating the desosaminylazithromycin and azithromycin related compound F peaks.] Tailing factor: , Standard Samples: Standard and Sample [NOTE Disregard peaks eluting before azithromycin 3 - N-oxide and after 3-deoxyazithromycin (azithromycin B). Disregard peaks with a response less than 0.1 times the response of the azithromycin peak in the Standard (0.1%).] Calculate the percentage of each related compound in the portion of Azithromycin taken: Result = (r U/r S) (C S/C U) P F 1 100/F 2

4 2282 Azithromycin / Official Monographs USP 35 Impurity Table 2 (Continued) Sample : 20 mg/ml, in dehydrated alcohol CRYSTALLINITY 695 : Meets the requirements except, where Relative it is labeled as amorphous, most of the particles do not Relative Response Acceptance exhibit birefringence and extinction positions Retention Factor Criteria, PH 791 : Name Time (F 2) NMT (%) Sample stock : 4 mg/ml in methanol Azithromycin C (3 - O Sample : 2 mg/ml from the Sample stock in demethylazithromycin) g a mixture of methanol and water (1:1) 3 -De(dimethylamino) WATER DETERMINATION, Method I oxoazithromycin h Where it is labeled as anhydrous: NMT 2.0% Azaerythromycin A i Where it is labeled as the dihydrate: 4.0% 5.0% Azithromycin impurity P j Where it is labeled as the monohydrate: 1.8% 4.0%, Azithromycin 1.0 except that it may be 4.0% 6.5% when the requirements of the Loss on Drying test are met 2-Desethyl LOSS ON DRYING: Where it is labeled as Azithromycin propylazithromycin k monohydrate and has a water content of 4.0% 6.5% (see 3 -N-Demethyl-3 -N-[( Thermal 891 ). methylphenyl)sulfonyl] [NOTE The quantity taken for this procedure may be azithromycin l adjusted, if necessar y, for instrument sensitivity.] 3-Deoxyazithromycin : Determine the per centage of volatile substances by (azithromycin B) m thermogravimetric analysis in an appropriately calibrated Any individual, instrument, using about 10 mg of Azithromycin. Heat the unidentified impurity specimen at the rate of 10 /min between ambient Total impurities 3.0 temperature and 150 in an atmosphere of nitrogen at a constant flow rate of about 35 ml/min. From the a (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- thermogram plot the derivatives of the loss on dr ying methyl-α-l-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxyweight loss steps at about 70 and 130. (percent loss/min), identify the inflection points of the two 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylazinoyl)-β-D Acceptance criteria: It loses NMT 4.5% of its weight b (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-Oabout 70, and 1.8% 2.6% between the inflection point at between ambient temperature and the inflection point at methyl-α-l-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxyabout 70 and the inflection point at about ,5,6,8,10,12,14-heptamethyl-11-[[3-formamido-3,4,6-trideoxy-β-D-xylohexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. c ADDITIONAL REQUIREMENTS (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- PACKAGING AND STORAGE: Preserve in tight containers. LABELING: Label it to indicate whether it is anhydrous, or the 3,5,6,8,10,12,14-heptamethyl-11-[[3-amino-3,4,6-trideoxy-β-D-xylomonohydrate or the dihydrate. The amorphous form is so hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. d labeled. Where the quantity of azithromycin is indicated in 3 -N-Demethyl-3 -N-formylazithromycin. e the labeling of any preparation containing Azithromycin, this (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-2-Ethyl-3,4,10,13-tetrahydroxyshall be understood to be in terms of anhydrous 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-Dazithromycin (C 38H 72N 2O 12). The labeling states with which f Organic Impurities procedure the article complies, if other (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-Othan Procedure 1. USP REFERENCE STANDARDS 11 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-methylamino-β-D-xylo- USP Azithromycin RS hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one. g USP Azaerythromycin A RS (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-α-L- USP Azithromycin Identity RS ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14- A mixture of azithromycin, 3 -(N-N-dimethyl-3 -N-formylheptamethyl-11-[[3,4,6-trideoxy-3-dimethylamino-β-D-xylo-hexopyranosyl] azithromycin, 3 -N-demethyl-3 -N-formylazithromycin oxy]-1-oxa-6-azacyclopentadecan-15-one. h (Rotamer 1), 3 -N-demethyl-3 -N-formylazithromycin (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3,3-dimethyl-α- (Rotamer 2), 3 -de(dimethylamino)-3 -oxoazithromycin, 2- L-ribo-hexopyranosyl)oxy]-2-ethyl-3,4,10-trihydroxy-3,5,6,8,10,12,14- desethyl-2-propylazithromycin, 3-deoxyazithromycin and heptamethyl-11-[[3,4,6-trideoxy-3-oxo-β-d-xylo-hexopyranosyl]oxy]-1-oxa- 3 -N-demethyl-3 -N-[(4-methylphenyl)sulfonyl] 6-azacyclopentadecan-15-one. i azithromycin. 9-Deoxo-9a-aza-9a-homoerythromycin A. j USP Desosaminylazithromycin RS Specified unidentified impurity. k USP N-Demethylazithromycin RS (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3- methyl-α-l-ribo-hexopyranosyl)oxy]-2-propyl-3,4,10-trihydroxy- C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl- 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-D- 3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[ xylo-hexopyranosyl]oxy]-1-oxa-6-azacyclopentadecan-15-one dihydrate. l [3,4,6-trideoxy-3-methylamino-β-D-xylo-hexopyranosyl] (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-Ooxy]-1-oxa-6-azacyclopentadecan-15-one. C 37H 70N 2O ,5,6,8,10,12,14-heptamethyl-11-[[3-[N-(4-methylphenylsulfonyl)-N- USP Azithromycin Related Compound F RS methylamino]-3,4,6-trideoxy-β-d-xylo-hexopyranosyl]oxy]-1-oxa-6- (2R,3S,4R,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3- azacyclopentadecan-15-one. m C-methyl-3-O-methyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl- (2R,3R,4S,5R,8R,10R,11R,12S,13S,14R)-13-[(2,6-Dideoxy-3-C-methyl-3-O- 3,4,10-trihydroxy-3,5,6,8,10,12,14-heptamethyl-11-[[3-(Nmethyl-α-L-ribo-hexopyranosyl)oxy]-2-ethyl-4,10-dihydroxymethyl)formamido-3,4,6-trideoxy-β-D-xylo-hexopyranosyl] 3,5,6,8,10,12,14-heptamethyl-11-[[3,4,6-trideoxy-3-(dimethylamino)-β-Doxy]-1-oxa-6-azacyclopentadecan-15-one. C 38H 70N 2O SPECIFIC TESTS OPTICAL ROTATION, Specific Rotation 781S : 45 to 49, at 20

5 . Tailing USP 35 Official Monographs / Azithromycin 2283 Azithromycin Capsules factor: , Standard Relative standard deviation: NMT 2.0%, Standard Samples: Standard and Sample Calculate the percentage of the labeled amount of azithro- mycin (C 38H 72N 2O 12) in the portion of Capsules taken: DEFINITION Azithromycin Capsules contain the equivalent of NL T 90.0% and NMT 110.0% of the labeled amount of azithromycin (C 38H 72N 2O 12). Result = ( r U/r S) (C S/C U) P F 100 IDENTIFICATION A. The retention time of the azithromycin peak of the Sam- ple corresponds to that of the Standard, as obtained in the Assay. r U = peak response from the Sample r S = peak response from the Standard C S = concentration of USP Azithromycin RS in the Standard (µg/ml) C U = nominal concentration of azithromycin in the Sample (µg/ml) P = potency of azithromycin in USP Azithromycin RS (µg/mg) F = conversion factor, mg/ µg Acceptance criteria: 90.0% 110.0% ASSAY PROCEDURE [NOTE Use water that has a resistivity of NL T 18 Mohmcm.] Mobile phase: Dissolve 5.8 g of monobasic potassium phosphate in 2130 ml of water, and add 870 ml of acetonitrile. Adjust with about 6 ml of 10 N potassium hydroxide to a ph of 11.0 ± 0.1, and pass through a suitable filter. PERFORMANCE TESTS Standard stock : mg/ml of USP Azithro- DISSOLUTION 711 mycin RS in acetonitrile. Swirl, and sonicate as necessar y. Standard : 3.3 µg/ml of USP Azithromycin RS from cm.] the Standard stock in Mobile phase Medium: ph 6.0 sodium phosphate buffer (Prepare 6 L of stock : 0.16 mg/ml of USP 0.1 M dibasic sodium phosphate. Adjust with about 40 ml Azaerythromycin A RS in acetonitrile and Mobile phase (1:9). of hydrochloric acid to a ph of 6.0 ± 0.05, and add 600 mg Dissolve first in acetonitrile, using 10% of the final volume. of trypsin); 900 ml Swirl, and sonicate to dissolve. Dilute with Mobile phase to Apparatus 2: 100 rpm volume. Time: 45 min : 3.2 µg/ml of azaer ythromycin Mobile phase,, and System A from the stock and 3.3 µg/ml of suitability: Proceed as directed in the Assay. azithromycin from the Standard stock in Mobile Standard stock : 0.3 mg/ml of USP Azithromycin phase RS in Medium. Sonicate briefly to dissolve. Sample stock : Remove, as completely as possible, Standard : 3.84 µg/ml of azithromycin from the the contents of NL T 20 Capsules. Prepare a 1-mg/mL solu- Standard stock in Mobile phase tion of anhydrous azithromycin in acetonitrile. Dissolve a Sample : Pass a portion of the under test portion of the mixed Capsule contents first in 70% of the through a suitable filter of 0.5- µm or finer pore size. T ransfer final volume of acetonitrile, and shake by mechanical means 2.0 ml of the filtrate to a 25-mL volumetric flask, and dilute for 30 min. Dilute with acetonitrile to volume. Place 40 ml with Mobile phase to volume. Transfer 4.0 ml of this of the resulting suspension in a centrifuge tube, and centri to a second 25-mL volumetric flask, and dilute with fuge. Use the supernatant to prepare the Sample. Mobile phase to volume. Sample : 3.2 µg/ml of azithromycin from the Sam- ple stock in Mobile phase Samples: Standard and Sample Determine the amount of azithromycin (C 38H 72N 2O 12) dissolved using the procedure in the Assay, making any necessary modifications. Calculate the percentage of azithromycin (C Electrode: Dual glassy carbon electrodes 38H 72N 2O 12) dissolved: Mode: Oxidative screen mode Electrode 1: ± 0.05 V Result = ( r U/r S) (C S/L) D V 100 Electrode 2: ± 0.05 V Background current: 85 ± 15 nanoampheres r U = peak response from the Sample Columns r S = peak response from the Standard Guard: 4.6-mm 5-cm; 5- µm packing L29 C S = concentration of USP Azithromycin RS in the Analytical: 4.6-mm 15-cm; 5- µm packing L29 or 3- µm Standard (mg/ml) packing L49 without the guard column L = label claim (mg/capsule) Flow rate: 1.5 ml/min D = dilution factor of the Sample Injection size: 50 µl V = volume of Medium, 900 ml Tolerances: NLT 75% ( Q) of the labeled amount of Samples: Standard and azithromycin (C 38H 72N 2O 12) is dissolved. [NOTE The relative retention times for azaer ythromycin A UNIFORMITY OF DOSAGE UNITS 905 : Meet the requirements and azithromycin with the L29 column are 0.7 and 1.0, respectively; the relative retention times for azaer ythromy- SPECIFIC TESTS cin A and azithromycin with the L49 column are 0.8 and WATER DETERMINATION, Method I 921 : NMT 5.0% 1.0, respectively.] ADDITIONAL REQUIREMENTS Re: NLT 2.5 between azaer ythromycin A and PACKAGING AND STORAGE: Preserve in well-closed containers. azithromycin, Where packaged in unit-of-use containers, each container Column efficiency: NLT 1000 theoretical plates, Stanintended sequential day of use for each contains six 250-mg Capsules, and the label indicates the dard Capsule.