Cloxacillin Benzathine
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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-,[2S-(2a,5a,6b)]-,compd.with N,N¢-bis(phenyl-methyl)-1,2-ethanediamine (2:1).
(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-carboxylic acid compound with N,N¢-dibenzylethylenediamine (2:1) [23736-58-5].
»Cloxacillin Benzathine has a potency equivalent to not less than 704µg and not more than 821µg of cloxacillin (C19H18ClN3O5S)per mg,calculated on the anhydrous basis.
Packaging and storage—
Preserve in tight containers.
Labeling—
Label it to indicate that it is for veterinary use only.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.
Identification—
A:
Infrared Absorption á197Kñ.
Solutions:
Obtain the test solution as follows.To about 20mg in a 50-mLconical flask,add 5mLof 5Nsodium hydroxide,and heat on a steam bath for 20minutes.Cool,transfer 1mLof this solution to a separator containing 10mLof 1.2Nsulfuric acid,and extract with 50mLof ether.Wash the ether extract with 30mLof water,and extract the ether layer with 50mLof 0.1Nsodium hydroxide.Similarly prepare the Standard solution from about 15mg of USP Cloxacillin Sodium RS.
Crystallinity á695ñ:
meets the requirements.
pHá791ñ:
between 3.0and 6.5,in a suspension containing 10mg per mL.
Sterility á71ñ—
Where the label states that Cloxacillin Benzathine 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.
Water,Method Iá921ñ:
not more than 5.0%.
Assay—
Proceed as directed for cloxacillin under Antibiotics—Microbial Assays á81ñ,using an accurately weighed quantity of Cloxacillin Benzathine dissolved quantitatively in methanol to yield a stock solution having a convenient concentration.Promptly dilute an accurately measured volume of this stock solution quantitatively and stepwise with Buffer No.1to obtain a Test Dilutionhaving a concentration assumed to be equal to the median dose level of the Standard.
Auxiliary Information—
Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 524
Phone Number:1-301-816-8178