Cloxacillin Sodium
;)
4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,6-[[[3-(2-chlorophenyl)-5-methyl-4-isoxazolyl]carbonyl]amino]-3,3-dimethyl-7-oxo-,monosodium salt,monohydrate,[2S-(2a,5a,6b)]-.
Monosodium (2S,5R,6R)-6-[3-(o-chlorophenyl)-5-methyl-4-isoxazolecarboxamido]-3,3-dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylate monohydrate [7081-44-9].
Anhydrous 457.87 [642-78-4].
»Cloxacillin Sodium contains the equivalent of not less than 825µg of cloxacillin (C19H18ClN3O5S)per mg.
Packaging and storage—
Preserve in tight containers,and store at a temperature not exceeding 25
.
.
Labeling—
Where it is intended for use in preparing sterile dosage forms,the label states that it is sterile or must be subjected to further processing during the preparation of sterile dosage forms.
Crystallinity á695ñ:
meets the requirements.
Sterility á71ñ—
Where the label states that Cloxacillin Sodium is sterile,it meets the requirements when tested as directed for Direct Inoculation of the Culture Mediumunder Test for Sterility of the Product to be Examined,except to use Fluid Thioglycollate Medium containing polysorbate 80solution (1in 200)and an amount of sterile penicillinase sufficient to inactivate the cloxacillin in each tube,to use Soybean–Casein Digest Medium containing polysorbate 80solution (1in 200)and an amount of sterile penicillinase sufficient to inactivate the cloxacillin in each tube,and to shake the tubes once daily.
pHá791ñ:
between 4.5and 7.5,in a solution containing 10mg per mL.
Water,Method Iá921ñ:
between 3.0%and 5.0%.
Dimethylaniline á223ñ:
meets the requirement.
Assay—
Buffer—
Prepare a 0.02Msolution of monobasic potassium phosphate in water,and adjust with 2Nsodium hydroxide to a pHof 6.8.
Mobile phase—
Prepare a mixture ofBuffer and acetonitrile (80:20).Make adjustments if necessary (see System Suitabilityunder Chromatography á621ñ).
Standard preparation—
Prepare a solution of USP Cloxacillin Sodium RSin Bufferhaving a known concentration of about 0.55mg per mL.
Assay preparation—
Transfer about 110mg of Cloxacillin Sodium,accurately weighed,to a 200-mLvolumetric flask,dilute with Bufferto volume,and mix.Stir with the aid of a magnetic stirrer for 5minutes to dissolve.
Chromatographic system (seeChromatography á621ñ)—
The liquid chromatograph is equipped with a 225-nm detector and a 4.6-mm ×25-cm column that contains packing L1.The flow rate is about 1mLper minute.Chromatograph the Standard preparation,and record the peak responses as directed for Procedure:the tailing factor is not more than 1.8;and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure—
Separately inject equal volumes (about 20µL)of the Standard preparationand the Assay preparationinto the chromatograph,record the chromatograms,and measure the responses for the major peaks.Calculate the quantity,in µg,of cloxacillin (C19H18ClN3O5S)in each mg of Cloxacillin Sodium taken by the formula:
200(CE/W)(rU/rS),
in which Cis the concentration,in mg per mL,of USP Cloxacillin Sodium RSin the Standard preparation;Eis the cloxacillin (C19H18ClN3O5S)equivalent,in µg per mg,of USP Cloxacillin Sodium RS;Wis the weight,in mg,of Cloxacillin Sodium taken to prepare theAssay preparation;and rUand rSare the cloxacillin peak responses obtained from the Assay preparationand the Standard preparation,respectively.
Auxiliary Information—
Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 525
Pharmacopeial Forum:Volume No.28(4)Page 1091
Phone Number:1-301-816-8335