Aluminum Zirconium Tetrachlorohydrate
AlyZr(OH)3y+4-xClx·nH2O
»Aluminum Zirconium Tetrachlorohydrate is a polymeric,loosely hydrated complex of basic aluminum zirconium chloride that encompasses a range of aluminum-to-zirconium atomic ratios between 2.0:1and 5.99:1and a range of (aluminum plus zirconium)-to-chloride atomic ratios between 1.5:1and 0.9:1.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of anhydrous aluminum zirconium tetrachlorohydrate.
Packaging and storage— Preserve in well-closed containers.
Labeling— The label states the content of anhydrous aluminum zirconium tetrachlorohydrate.
Identification— Asolution (1in 10)responds to the test for Chloride á191ñ.
pHá791ñ: between 3.0and 5.0,in a solution [15in 100(w/w)].
Heavy metals,Method Iá231ñ— Proceed as directed in the chapter,except to use the following modifications.
Test Preparation— Prepare as directed in the chapter.If the solution is not clear after dilution to 40mL,heat for several minutes between 60and 80,and cool to room temperature.If the solution remains cloudy,repeat from the beginning with the following modification:add 3mLof hydrochloric acid prior to adjustment of the pHwith 6Nammonium hydroxide.
Monitor Preparation— Prepare as directed in the chapter,using the same modifications described for Test Preparationif necessary.
Procedure— To each of the three tubes containing the Standard Preparation,the Test Preparation,and the Monitor Preparation,add 2mLof pH3.5Acetate Buffer,and heat gently to between 60and 80.To the Standard Preparationadd 6drops of sodium sulfide TS.To the Test Preparationand the Monitor Preparationadd 12drops of sodium sulfide TS.Cool to room temperature,and dilute the contents of each tube with water to 50mL.Gently mix each tube by inverting twice.Allow to stand for 5minutes,and view downward over a white surface.The color of the solution from the Test Preparationis not darker than that of the solution from the Standard Preparation,and the color of the solution from the Monitor Preparationis the same as or darker than the color of the solution from the Standard Preparation.If the color of the solution from the Monitor Preparationis lighter than the color of the solution from the Standard Preparation,repeat the procedure with the following modification:after the heating step,to the Monitor Preparationand the Test Preparationadd 1.0mL,instead of 12drops,of sodium sulfide TS.Not more than 20µg per g is found.
Limit of iron— Using Aluminum Zirconium Tetrachlorohydrate instead of Aluminum Zirconium Octachlorohydrate,proceed as directed in the test for Limit of ironunder Aluminum Zirconium Octachlorohydrate.The specified result is obtained (150µg per g limit).
Content of aluminum— Using Aluminum Zirconium Tetrachlorohydrate instead of Aluminum Zirconium Octachlorohydrate,proceed as directed in the test for Content of aluminumunder Aluminum Zirconium Octachlorohydrate.Use the result obtained to calculate the Aluminum/zirconium atomic ratioand the (Aluminum plus zirconium)/chloride atomic ratio.
Content of zirconium— Using Aluminum Zirconium Tetrachlorohydrate instead of Aluminum Zirconium Octachlorohydrate,proceed as directed in the test for Content of zirconiumunder Aluminum Zirconium Octachlorohydrate.Use the result obtained to calculate the Aluminum/zirconium atomic ratioand the (Aluminum plus zirconium)/chloride atomic ratio.
Aluminum/zirconium atomic ratio— Divide the percentage of aluminum found in the test for Content of aluminumby the percentage of zirconium found in the test for Content of zirconium,and multiply by 92.97/26.98,in which 92.97is the atomic weight of zirconium corrected for 2%hafnium content,and 26.98is the atomic weight of aluminum:the ratio is between 2.0:1and 5.99:1.
Content of chloride— Using Aluminum Zirconium Tetrachlorohydrate instead of Aluminum Zirconium Octachlorohydrate,proceed as directed in the test for Content of chlorideunder Aluminum Zirconium Octachlorohydrate.Use the result obtained to calculate the (Aluminum plus zirconium)/chloride atomic ratio.
(Aluminum plus zirconium)/chloride atomic ratio— Calculate the (aluminum plus zirconium)/chloride atomic ratio by the formula:
[(Al/26.98)+(Zr/92.97)]/(Cl/35.453),
in which Al,Zr,and Clare the percentages of aluminum,zirconium,and chloride as determined in the tests for Content of aluminum,Content of zirconium,and Content of chloride,respectively;26.98is the atomic weight of aluminum;92.97is the atomic weight of zirconium corrected for 2%hafnium content;and 35.453is the atomic weight of chlorine:the ratio is between 1.5:1and 0.9:1.
Assay— Calculate the percentage of anhydrous aluminum zirconium tetrachlorohydrate in the Aluminum Zirconium Tetrachlorohydrate by the formula:
Al({26.98y+92.97+17.01[3y+4-(y+1)/z]+35.453(y+1)/z}/26.98y),
in which Alis the percentage of aluminum found in the test for Content of aluminum,yis the aluminum/zirconium atomic ratio found in the test for Aluminum/zirconium atomic ratio,zis the (aluminum plus zirconium)/chloride atomic ratio found in the test for (Aluminum plus zirconium)/chloride atomic ratio,26.98is the atomic weight of aluminum,92.97is the atomic weight of zirconium corrected for 2%hafnium content,17.01is the molecular weight of the hydroxide anion (OH),and 35.453is the atomic weight of chlorine (Cl).
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(PA6)Pharmaceutical Analysis 6
USP28–NF23Page 104
Pharmacopeial Forum:Volume No.27(4)Page 2696
Phone Number:1-301-816-8389