Document R80GQ2Z7Lbjq7v3d7a558Ebz

FILE NAME: Talc (TALC) DATE: 2011 A u g i DOC#: TALC203 DOCUMENT DESCRIPTION: US Pharma Revised Bulletin on Talc Revision Bulletin Official August 1, 2011 Talc 1 Talc DEFINITION Talc is a powdered, selected, natural, hydrated magnesium silicate. Pure talc has the formula Mg3 Si4O-|0(OH)2 . It may contain variable amounts of associated minerals among which chlorites (hydrated aluminum and magnesium sili cates), magnesite (magnesium carbonate), calcite (cal cium carbonate), and dolomite (calcium and magnesium carbonate) are predominant. IDENTIFICATION A. Infrared A bsorption: The IR spectrum of a potas sium bromide dispersion of it exhibits maxima at 3677 2 cm-1, at 1018 2 cm-1, and at 669 2 cm-1. B. P rocedure Sample: 100 mg Analysis: Mix about 200 mg of anhydrous sodium car bonate and 2 g of anhydrous potassium carbonate, and melt in a platinum crucible. To the melt add the Sam ple, and continue heating until fusion is complete. Cool, and transfer the fused mixture to a dish or beaker with the aid of about 50 mL of hot water. Add hydrochloric acid to the liquid until effervescence ceases, then add 10 mL more of the acid, and evaporate the mixture on a steam bath to dryness. Cool, add 20 mL of water, boil, and filter the mixture. Save the insoluble residue for use in Identification test C. To 5 mL of the filtrate add 1 mL of 6 N ammonium hydroxide and 1 mL of ammonium chloride TS. Filter, if necessary, and add 1 mL of dibasic sodium phos phate TS to the filtrate. Acceptance criteria: A white, crystalline precipitate of magnesium ammonium phosphate is formed. C. Procedure Sample: 100 mg of the insoluble residue from Identifica tion test B Analysis: In a lead or platinum crucible and using a copper wire, mix the Sample with about 10 mg of so dium fluoride and a few drops of sulfuric acid to give a thin slurry. Cover the crucible with a thin transparent plate of plastic under which a drop of water is sus pended, and warm gently. Acceptance criteria: Within a short time, a white ring is rapidly formed around the drop of water. ASSAY Content of Magnesium Lanthanum chloride solution: To 5.9 g of lanthanum oxide slowly add 10 mL of hydrochloric acid, and heat to boiling. Allow to cool, and dilute with water to 100 mL. Magnesium standard stock solution: 10 |ig/mL of magnesium, prepared by diluting an 8.365 mg/mL solu tion of magnesium chloride in diluted hydrochloric acid with water (1 in 100) Magnesium standard solutions: Into four identical 100-mL volumetric flasks, each containing 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solu tion, transfer respectively 2.5, 3.0, 4.0, and 5.0 mL of Magnesium standard stock solution, and dilute with water to volume. Sample stock solution: [Caution-- Perchlorates mixed with heavy metals are known to be explosive. Take proper precautions while performing this analysis.] Weigh 500 mg of Talc in a 100-mL polytetrafluoroethyl- ene dish. Add 5 mL of hydrochloric acid, 5 mL of lead free nitric acid, and 5 mL of perchloric acid. Stir gently, then add 35 mL of hydrofluoric acid, and evaporate slowly on a hot plate to moist dryness (until about 0.5 mL remains). To the residue, add 5 mL of hydrochloric acid, cover with a watch glass, heat to boiling, and allow to cool. Rinse the watch glass and the dish with water, transfer to a 50-mL volumetric flask, and dilute with water to volume. Sample solution: Dilute the Sample stock solution with water (1 in 200). Transfer 4.0 mL of this solution to a 100-mL volumetric flask, add 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solution, and di lute with water to volume. Instrumental conditions (See Spectrophotometry and Light-Scattering (851).) Mode: Atomic absorption spectrophotometry Analytical wavelength: Magnesium emission line at 285.2 nm Lamp: Magnesium hollow-cathode Flame: Air-acetylene Analysis Samples: Magnesium standard solutions and Sample solution Concomitantly determine the absorbance of the solutions. Acceptance criteria: 17.0%-19.5% IM PU R ITIES W ater-Soluble Substances Sample: 10.0 g Analysis: To the Sample add 50 mL of carbon dioxide free water, heat to boiling, and boil under a reflux con denser for 30 min. Allow to cool, filter, and dilute with carbon dioxide-free water to 50.0 mL. Test with litmus paper. Evaporate 25.0 mL of the filtrate to dryness, dry at 105 for 1 h, and weigh the residue. Acceptance criteria: The filtrate is neutral to litmus pa per, and the weight of the residue is NMT 5 mg (0.1%). Limit of Iron Iron standard stock solution: 250 |ig/mL of iron from 4.840 g ferric chloride in a 150 g/L solution of hydro chloric acid in water. Prepare immediately before use. Iron standard solutions: Into four 100-mL volumetric flasks, each containing 50.0 mL of 0.5 N hydrochloric acid, transfer respectively 2.0, 2.5, 3.0, and 4.0 mL of the Standard iron stock solution, and dilute each flask with water to volume. Sample stock solution: Transfer 10.0 g of Talc to a conical flask fitted with a reflux condenser. Gradually add 50 mL of 0.5 N hydrochloric acid while stirring, and heat on a water bath for 30 min. Allow to cool. Transfer the mixture to a beaker, and allow the undissolved ma terial to settle. Filter the supernatant into a 100-mL vol umetric flask, retaining as much as possible of the insol uble material in the beaker. Wash the residue and the beaker with three 10-mL portions of hot water. Wash the filter with 15 mL of hot water, allow the filtrate to cool, and dilute with water to 100.0 mL. Sample solution: Transfer 2.5 mL of the Sample stock solution to a 100-mL volumetric flask, add 50.0 mL of 0.5 N hydrochloric acid, and dilute with water to volume. Instrumental conditions (See Spectrophotometry and Light-Scattering (851).) Mode: Atomic absorption spectrophotometry Analytical wavelength: Iron emission line at 248.3 nm Lamp: Iron hollow-cathode Flame: Air-acetylene Analysis Samples: Iron standard solutions and Sample solution Concomitantly determine the absorbance of the solu tions. Make any correction using a deuterium lamp. 2011 The United States Pharmacopeial Convention All Rights Reserved. 2 Talc Revision Bulletin Official August 1, 2011 Acceptance criteria: NMT 0.25% L imit of L ead Sample solution: Use the Sample stock solution as di rected in the test for Limit of Iron. Diluent: Nitric acid in water (1 in 100) Lead standard stock solution: 10 |xg/mL of lead pre pared as follows. Dissolve 160 mg of lead nitrate in 100 mL of Diluent, and dilute with water to 1000 mL. Dilute this solution with water (1 in 10). Lead standard solutions: Into four identical 100-mL volumetric flasks, each containing 50.0 mL of 0.5 N hy drochloric acid, transfer respectively 5.0, 7.5, 10.0, and 12.5 mL of Lead standard stock solution, and dilute with water to volume. Instrumental conditions (See Spectrophotometry and Light-Scattering (851).) Mode: Atomic absorption spectrophotometry Analytical wavelength: Lead emission line at 217.0 nm Lamp: Lead hollow-cathode Flame: Air-acetylene Analysis Samples: Lead standard solutions and Sample solution Concomitantly determine the absorbance of the solutions. Acceptance criteria: NMT 10 ppm L imit of Calcium Lanthanum chloride solution: Prepare as directed in the Assay. Calcium standard stock solution: 100 |xg/mL of cal cium, prepared immediately before use by diluting a 3.67 mg/mL solution of calcium chloride dihydrate in diluted "hydrochloric acid with water (1 in 10) Calcium standard solutions: Into four identical 100-mL volumetric flasks, each containing 10.0 mL of hydro chloric acid and 10 mL of Lanthanum chloride solution, transfer respectively 1.0, 2.0, 3.0, and 4.0 mL of Cal cium standard stock solution, and dilute each solution with water to volume. Sample stock solution: Prepare as directed in the Assay. Sample solution: Transfer 5.0 mL of the Sample stock solution to a 100-mL volumetric flask, add 10.0 mL of hydrochloric acid and 10 mL of Lanthanum chloride solu tion, and dilute with water to volume. Instrumental conditions (See Spectrophotometry and Light-Scattering (851).) Mode: Atomic absorption spectrophotometry Analytical wavelength: Calcium emission line at 422.7 nm Lamp: Calcium hollow-cathode Flame: Nitrous oxide-acetylene Analysis Samples: Calcium standard solutions and Sample solution Concomitantly determine the absorbance of the solutions. Acceptance criteria: NMT 0.9% L imit of A luminum Cesium chloride solution: 25.3 mg/mL of cesium chlo ride in water. Aluminum standard stock solution: 100 |xg/mL of alu minum, prepared immediately before use by diluting an 8.947 mg/mL solution of aluminum chloride in water with water (1 in 10) Aluminum standard solutions: Into four identical 100 mL volumetric flasks, each containing 10.0 mL of hydro chloric acid and 10 mL of Cesium chloride solution, trans fer respectively 5.0, 10.0, 15.0, and 20.0 mL of Alumi num standard stock solution, and dilute with water to volume. Sample stock solution: Proceed as directed in the As say. Transfer 5 mL of the Cesium chloride solution to the 50-mL flask prior to transfer of the residue, and dilute with water to volume. Sample solution: Transfer 5.0 mL of the Sample stock solution to a 100-mL volumetric flask, add 10 mL of the Cesium chloride solution and 10.0 mL of hydrochloric acid, and dilute with water to volume. Instrumental conditions (See Spectrophotometry and Light-Scattering (851).) Mode: Atomic absorption spectrophotometry Analytical wavelength: Aluminum emission line at 309.3 nm Lamp: Aluminum hollow-cathode Flame: Nitrous oxide-acetylene Analysis Samples: Aluminum standard solutions and Sample solution Concomitantly determine the absorbance of the solutions. Acceptance criteria: NMT 2.0% A bsence of A sbestos [Note--Suppliers of Talc may use one of the following methods to determine the absence of asbestos.] Proceed as directed for Procedure 1 or Procedure 2. If either test is positive, perform Procedure 3. Procedure 1: Infrared Absorption The IR absorption spectrum of a potassium bromide dis persion of Talc at the absorption band at 758 1 cm-1, using scale expansion, may indicate the presence of tremolite or chlorite. If the absorption band remains after ignition of the substance at 850 for at least 30 min, it indicates the presence of tremolite. In the range 600 cm-1 to 650 cm-1 using scale expansion, any ab sorption band or shoulder may indicate the presence of serpentines. Procedure 2: Use the following conditions (see X-Ray Diffraction (941)): Cu Ka monochromatic 40 kV radiation, 24-30 mA; the incident slit is set at 1; the detection slit is set at 0.2; the goniometer speed is 1/10 20/min; the scanning range is 10-13 20 and 24-26 20; the sample is not oriented. Prepare a random sample, and place on the sample holder. Pack and smooth its surface with a polished glass microscope slide. Record the diffractograms: the presence of amphiboles is detected by a diffraction peak at 10.5 0.1 20, and the presence of serpentines is detected by diffraction peaks at 24.3 0.1 20 to 12.1 0.1 20. Procedure 3: The presence of asbestos (see Optical Mi croscopy (776)) is shown if there is a range of length to width ratios of 20:1 to 100:1, or higher for fibers longer than 5 |xm; if there is a capability of splitting into very thin fibrils; and if there are two or more of the following four criteria: (1) parallel fibers occurring in bundles, (2) fiber bundles displaying frayed ends, (3) fibers in the form of thin needles, and (4) matted masses of individ ual fibers and/or fibers showing curvature. SPECIFIC TESTS Microbial Enumeration T ests (61) and T ests for Speci fied Microorganisms (62) Intended for topical administration Total aerobic microbial count: NMT 100 cfu/g Total combined molds and yeasts count: NMT 50 cfu /g Intended for oral administration Total aerobic microbial count: NMT 1000 cfu/g Total combined molds and yeasts count: NMT 100 cfu/g A cidity and A lkalinity: Boil 2.5 g of Talc with 50 mL of carbon dioxide-free water under reflux. Filter under vac 2011 The United States Pharmacopeial Convention All Rights Reserved. Revision Bulletin Official August 1, 2011 Talc 3 uum. To 10 mL of the filtrate, add 0.1 mL of bromothymol blue TS. Add 0.01 N hydrochloric acid un til the indicator changes color. To a second 10 mL of the filtrate, add 0.1 mL of phenolphthalein TS. Add 0.01 N sodium hydroxide until the indicator turns pink. Acceptance criteria: NMT 0.4 mL of 0.01 N hydrochlo ric acid is required to change the color of the bromothymol blue indicator. NMT 0.3 mL of 0.01 N so dium hydroxide is required to change the color of the phenolpthalein indicator to pink. Loss on Ignition (733) Sample: 1 g Analysis: Ignite at 1075 25 to constant weight. Acceptance criteria: It loses NMT 7.0% of its weight. ADDITIONAL REQUIREMENTS Packaging and Storage: Preserve in well-closed con tainers. No storage requirements specified. Labeling: The label states, where applicable, that the substance is suitable for oral or topical administration. The certificate of analysis states the absence of asbestos. It also indicates which method specified in the test for Absence of Asbestos was used for analysis. Change to read: Labeling: The label states, where applicable, that the substance is suitable for oral or topical administration. The certificate of analysis states the absence of asbestos. It also indicates that Talc is not derived from deposits that are known to contain associated asbestos, and^ (RB1-Aug-2011) which method specified in the test for Absence of Asbestos was used for analysis. (Postponed indefinitely)^ 1-Aug-2011) 2011 The United States Pharmacopeia! Convention All Rights Reserved.