Tetracycline Hydrochloride Ophthalmic Suspension »Tetracycline Hydrochloride Ophthalmic Suspension is a sterile suspension of sterile Tetracycline Hydrochloride in a suitable oil.It contains not less than 90.0percent and not more than 125.0percent of the labeled amount of C22H24N2O8·HCl. Packaging and storage— Preserve in tight,light-resistant containers of glass or plastic,containing not more than 15mL.The containers or individual cartons are sealed and tamper-proof so that sterility is assured at time of first use. USP Reference standards á11ñ USP Tetracycline Hydrochloride RS.USP4-Epianhydrotetracycline Hydrochloride RS. Identification— The chromatogram of the Assay preparationobtained as directed in the Assayexhibits a major peak for tetracycline,the retention time of which corresponds to that exhibited in the chromatogram of the Standard preparationobtained as directed in the Assay. Sterility á71ñ: meets the requirements. Water,Method Iá921ñ: not more than 0.5%,20mLof a mixture of toluene and methanol (7:3)being used in place of methanol in the titration vessel. Assay— Diluting solvent,Mobile phase,Standard preparation,Resolution solution,andChromatographic system— Prepare as directed in the Assayunder Tetracycline Hydrochloride. Assay preparation— Transfer an accurately measured volume of Ophthalmic Suspension,equivalent to about 50mg of tetracycline hydrochloride,with the aid of 30mLof cyclohexane to a 125-mLseparator,add 30mLof Diluting solvent,insert the stopper,and shake.Allow to separate,and collect the lower layer in a 100-mLvolumetric flask.Repeat the extraction with two additional 30-mLportions of Diluting solvent,combining the extracts in the 100-mLvolumetric flask.Add Diluting solventto volume,mix,and filter. Procedure— Proceed as directed for Procedurein the Assayunder Tetracycline Hydrochloride.Calculate the quantity,in mg per mL,of C22H24N2O8·HCl equivalent in the Ophthalmic Suspension taken by the formula: (CP/10V)(rU/rS), in which Vis the volume,in mL,of Ophthalmic Suspension taken,and the other terms are as defined therein. Auxiliary Information— Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow Expert Committee:(PA7)Pharmaceutical Analysis 7 USP28–NF23Page 1889 Phone Number:1-301-816-8335