Penicillin V Benzathine
;)
4-Thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid,3,3-dimethyl-7-oxo-6-[(2-phenoxyacetyl)amino-],[2S-(2a,5a,6b)]-,compd.with N,N¢-bis(phenylmethyl)-1,2-ethanediamine (2:1).
(2S,5R,6R)-3,3-Dimethyl-7-oxo-6-(2-phenoxyacetamido)-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic acid compound with N,N¢-dibenzylethylenediamine (2:1) [5928-84-7].
Tetrahydrate 1013.21 [63690-57-3].
»Penicillin V Benzathine has a potency of not less than 1060and not more than 1240Penicillin V Units per mg.
Packaging and storage—
Preserve in tight containers.
Crystallinity á695ñ:
meets the requirements.
pHá791ñ:
between 4.0and 6.5,in a suspension containing about 30mg per mL.
Water,Method Iá921ñ:
between 5.0%and 8.0%.
Penicillin Vcontent—
Transfer about 40mg,accurately weighed,to a 100-mLvolumetric flask,add methanol to volume,and mix.Concomitantly determine the absorbances of this solution and of a similarly prepared Standard solution prepared with about 30mg of USP Penicillin V Potassium RSat the wavelength of maximum absorbance at about 276nm.Determine the percentage of penicillin Vtaken by the formula:
P(aU/aS),
in which Pis the percentage content of penicillin Vin the USP Penicillin V Potassium RS,and aUand aSare the absorptivities of the solution of the specimen and the Standard solution,respectively:between 62.3%and 72.5%is found.
Assay—
Standard preparation—
Prepare as directed for Standard preparationunder Iodometric Assay—Antibiotics á425ñ,using USP Penicillin V Potassium RS.
Assay preparations—
Dissolve a quantity of Penicillin V Benzathine in 1.0Nsodium hydroxide to obtain a solution containing 2000Penicillin V Units per mL.Pipet 2mLof this solution into a glass-stoppered,125-mLconical flask,and use as the Assay preparationfor Inactivation and titration.Dilute a quantity of Penicillin V Benzathine quantitatively with water to obtain a suspension containing 2000Penicillin V Units per mL.Pipet 2mLof this suspension into a glass-stoppered,125-mLconical flask,and use as the Assay preparationfor the Blank determination.
Procedure—
Proceed as directed for Procedureunder Iodometric Assay—Antibiotics á425ñ,except in the Inactivation and titrationof the specimen to omit the addition of 2.0mLof 1.0Nsodium hydroxide.Calculate the potency,in Penicillin V Units per mg,in the Penicillin V Benzathine taken by the formula:
(F)(B-I)/(2D),
in which Dis the concentration,in mg per mL,of the Assay preparationfor Inactivation and titrationon the basis of the weight of Penicillin V Benzathine taken and the extent of dilution.
Auxiliary Information—
Staff Liaison:William W.Wright,Ph.D.,Scientific Fellow
Expert Committee:(PA7)Pharmaceutical Analysis 7
USP28–NF23Page 1498
Phone Number:1-301-816-8335