Benztropine Mesylate Injection
»Benztropine Mesylate Injection is a sterile solution of Benztropine Mesylate in Water for Injection.It contains not less than 90.0percent and not more than 110.0percent of the labeled amount of C21H25NO·CH4O3S.
Packaging and storage— Preserve in single-dose or in multiple-dose containers,preferably of Type Iglass.
Identification— Dissolve about 10mg of USP Benztropine Mesylate RSin 50mLof water in a separator to obtain a solution containing about 0.2mg per mL.Transfer a volume of Injection,equivalent to about 10mg of benztropine mesylate,to a second separator,and dilute with water to 50mL.Separately add 2mLof 1Nsodium hydroxide to each separator,and mix.Extract each solution with three 10-mLportions of chloroform,collecting the chloroform extracts from both solutions in separate 50-mLbeakers.Evaporate both chloroform extracts with the aid of gentle heat and a current of air to dryness,and separately dissolve each residue in 1mLof chloroform.Apply separately 1µLof the test solution and the Standard solution to a suitable thin-layer chromatographic plate (see Chromatography á621ñ)coated with a 0.25-mm layer of chromatographic silica gel.Allow the applications to dry,and develop the chromatogram in a solvent system consisting of a mixture of chloroform,methanol,and a 1in 4solution of ammonium hydroxide (40:10:1)until the solvent front has moved about three-fourths of the length of the plate.Remove the plate from the developing chamber,mark the solvent front,and allow the solvent to evaporate.Locate the spots on the plate by lightly spraying with potassium iodoplatinate TS:the RFvalue of the principal spot obtained from the test solution corresponds to that obtained from the Standard solution.
Bacterial endotoxins á85ñ— It contains not more than 55.6USP Endotoxin Units per mg of benztropine mesylate.
pHá791ñ: between 5.0and 8.0.
Other requirements— It meets the requirements under Injections á1ñ.
Assay—
0.005M Octylamine phosphate buffer— Transfer 0.83mLof octylamine to a 1-liter volumetric flask,dilute with water to volume,adjust with phosphoric acid to a pHof 3.0,and pass the solution through a membrane filter.
Mobile phase— Mix 350mLof 0.005M Octylamine phosphate bufferand 650mLof acetonitrile,and degas the solution.
Standard preparation— Dissolve an accurately weighed quantity of USP Benztropine Mesylate RSin water to obtain a solution having a known concentration of about 1mg per mL.
Assay preparation— Dilute with water an accurately measured volume of Injection,equivalent to about 10mg of benztropine mesylate,to obtain a solution having a concentration of about 1mg of benztropine mesylate per mL.
Chromatographic system (see Chromatography á621ñ)—The liquid chromatograph is equipped with a 259-nm detector and a 4.6-mm ×25-cm column that contains packing L7.The flow rate is about 1.3mLper minute.Adjust the flow rate to obtain a retention time of about 7minutes for benztropine mesylate.Chromatograph replicate injections of the Standard preparation,and record the peak responses as directed for Procedure:the relative standard deviation is not more than 2.0%.
Procedure— Separately inject equal volumes (about 25µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the peak areas for the major peaks.Calculate the quantity,in mg,of C21H25NO·CH4O3Sin each mLof the Injection taken by the formula:
10(C/V)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Benztropine Mesylate RSin the Standard preparation,Vis the volume,in mL,of Injection taken,and rUand rSare the peak areas obtained for benztropine mesylate from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information— Staff Liaison:Salvador C.Salado,M.S.,Scientist and Latin American Liaison
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 238
Phone Number:1-301-816-8165