Tetracaine Hydrochloride in Dextrose Injection »Tetracaine Hydrochloride in Dextrose Injection is a sterile solution of Tetracaine Hydrochloride and Dextrose in Water for Injection.It contains not less than 95.0percent and not more than 105.0percent of the labeled amounts of tetracaine hydrochloride (C15H24N2O2·HCl)and dextrose (C6H12O6). Packaging and storage— Preserve in single-dose or multiple-dose containers,preferably of Type Iglass,under refrigeration and protected from light.It may be packaged in 100-mLmultiple-dose containers.Injection supplied as a component of spinal anesthesia trays may be stored at room temperature for 12months. Labeling— Label it to indicate that the Injection is not to be used if it contains crystals,or if it is cloudy or discolored. USP Reference standards á11ñ USP Endotoxin RS.USP Tetracaine Hydrochloride RS. Identification— A:Ultraviolet Absorption á197Uñ: Assay preparation,compared to the Standard preparationfrom the Assay. B: It responds to Identificationtest Cunder Tetracaine Hydrochloride. C: It responds to the Identificationtest under Dextrose. Bacterial endotoxins á85ñ It contains not more than 1.0USP Endotoxin Unit per mg of tetracaine hydrochloride. pHá791ñ: between 3.5and 6.0 Particulate matter á788ñ: meets the requirements under small-volume injections. Other requirements— It meets the requirements under Injections á1ñ. Assay— Standard preparation— Dissolve about 20mg of USP Tetracaine Hydrochloride RS,accurately weighed,in water to make 100.0mL,and mix.Pipet 5mLof this solution into a 100-mLvolumetric flask,add 5mLof dilute hydrochloric acid (1in 200)and 10mLof Buffer No.6,10percent,pH6.0(see Phosphate Buffers á81ñ),dilute with water to volume,and mix. Assay preparation— Transfer an accurately measured volume of Injection,equivalent to about 10mg of tetracaine hydrochloride,to a separator,dilute with water to about 50mL,and render alkaline by the addition of 5mLof sodium carbonate TS.Extract immediately with two 50-mLportions of ether,collecting the extracts in a separator.Wash the ether extracts with 20mLof water,discarding the wash solution,and extract the ether solution with two 20-mLportions and one 5-mLportion of dilute hydrochloric acid (1in 200),collecting the extracts in a 50-mLvolumetric flask.Dilute with water to volume,and mix.Transfer a 5.0-mLaliquot to a 100-mLvolumetric flask,add 10mLof Buffer No.6,10percent,pH6.0(see Phosphate Buffers á81ñ),dilute with water to volume,and mix. Procedure— Concomitantly determine the absorbances of the Assay preparationand the Standard preparationat the wavelength of maximum absorbance at about 310nm,with a suitable spectrophotometer,using water as the blank.Calculate the quantity,in mg,of tetracaine hydrochloride (C15H24N2O2·HCl)in the volume of Injection taken by the formula: C(AU/AS), in which Cis the concentration,in µg per mL,of USP Tetracaine Hydrochloride RSin the Standard preparation;and AUand ASare the absorbances of the Assay preparationand the Standard preparation,respectively. Assay for dextrose— Determine the angular rotation of Injection in a suitable polarimeter tube (see Optical Rotation á781ñ).The observed rotation,in degrees,multiplied by 9.452A,in which Ais the ratio of 200divided by the length,in mm,of the polarimeter tube employed,represents the weight,in mg,of dextrose (C6H12O6)in each mLof the Injection. Auxiliary Information— Staff Liaison:Karen A Russo,Ph.D.,Scientist Expert Committee:(PA1)Pharmaceutical Analysis 1 USP28–NF23Page 1884 Pharmacopeial Forum:Volume No.30(5)Page 1648 Phone Number:1-301-816-8379