Theophylline in Dextrose Injection »Theophylline in Dextrose Injection is a sterile solution of Theophylline and Dextrose in Water for Injection.It contains not less than 93.0percent and not more than 107.0percent of the labeled amount of anhydrous theophylline (C7H8N4O2)and not less than 95.0percent and not more than 105.0percent of the labeled amount of dextrose (C6H12O6·H2O). Packaging and storage— Preserve in single-dose containers,preferably of Type Ior Type IIglass,or of a suitable plastic material. USP Reference standards á11ñ USP Endotoxin RS.USP Theophylline RS. Identification— A: The UVabsorption spectrum of the Injection,diluted with 0.5Nsodium hydroxide to a concentration of about 8µg of anhydrous theophylline per mL,exhibits maxima and minima at the same wavelengths as that of a similar solution of USP Theophylline RS,concomitantly measured. B: Add a few drops of the Injection to 5mLof hot alkaline cupric tartrate TS:a red to orange precipitate of cuprous oxide is formed. Bacterial endotoxins á85ñ It contains not more than 1.0USP Endotoxin Unit per mg of anhydrous theophylline. pHá791ñ: between 3.5and 6.5,determined on a portion diluted with water,if necessary,to a concentration of not more than 5%of dextrose. Limit of 5-hydroxymethylfurfural and related substances— Cation-exchange column— Proceed as directed under Column Partition Chromatography(see Chromatography á621ñ),using a chromatographic tube capable of providing a 0.8-×4-cm bed volume (or about 2mL)of 100-to 200-mesh,strongly acidic,styrene-divinylbenzene,cation-exchange resin.Condition the column by washing with about 30mLof water,discarding the eluate. Procedure— Pass a volume of Injection containing about 100mg of hydrous dextrose through the resin bed in the Cation-exchange column,allowing the specimen to flow down the wall of the column so as not to disturb the resin bed,and collect the eluate in a 50-mLvolumetric flask.Wash the column with 25mLof water,and collect the eluate in the same 50-mLvolumetric flask.Dilute the eluate with water to volume,and mix to obtain the Test solution.In a similar manner,prepare a Reference solutionby passing 27mLof water through a freshly conditioned Cation-exchange column,collecting the eluate in a 50-mLvolumetric flask.Dilute with water to volume,and mix.Determine the absorbance of the Test solutionin a 1-cm cell at 284nm,with a suitable spectrophotometer,using the Reference solutionas the blank:the absorbance is not more than 0.25. Other requirements— It meets the requirements under Injections á1ñ. Assay for theophylline— Buffer solution, Mobile phase,and Internal standard solution—Prepare as directed in the Assayunder Theophylline. Standard preparation— Dissolve an accurately weighed quantity of USP Theophylline RSin Mobile phase,and dilute quantitatively,and stepwise if necessary,with Mobile phaseto obtain a solution having a known concentration of about 1mg per mL.Transfer 8.0mLof this solution to a 50-mLvolumetric flask,add 10.0mLof Internal standard solution,dilute with Mobile phaseto volume,and mix to obtain a solution having a known concentration of about 0.16mg of USP Theophylline RSper mL. Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 16mg of theophylline,to a 100-mLvolumetric flask,add 20.0mLof Internal standard solution,dilute with Mobile phaseto volume,and mix. Chromatographic system— Proceed as directed in the Assayunder Theophylline. Procedure— Proceed as directed for Procedurein the Assayunder Theophylline.Calculate the quantity,in mg,of C7H8N4O2in each mLof the Injection taken by the formula: (100C/V)(RU/RS), in which Vis the volume,in mL,of Injection taken,and the other terms are as defined therein. Assay for dextrose— Transfer an accurately measured volume of Injection,containing 2to 5g of dextrose,to a 100-mLvolumetric flask.Add 0.2mLof 6Nammonium hydroxide,dilute with water to volume,and mix.Determine the angular rotation in a suitable polarimeter tube at 25(see Optical Rotation á781ñ).The observed rotation,in degrees multiplied by 1.0425A,in which Ais the ratio 200divided by the length,in mm,of the polarimeter tube employed,represents the weight,in g,of C6H12O6·H2Oin the volume of Injection taken. Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist Expert Committee:(PA1)Pharmaceutical Analysis 1 USP28–NF23Page 1899 Pharmacopeial Forum:Volume No.30(5)Page 1649 Phone Number:1-301-816-8379