Chlortetracycline Bisulfate
»Chlortetracycline Bisulfate has a potency equivalent to not less than 760µg of chlortetracycline hydrochloride (C22H23ClN2O8·HCl)per mg,calculated on the dried and butyl alcohol-free basis.
Packaging and storage— Preserve in tight,light-resistant containers.
Labeling— Label it to indicate that it is intended for veterinary use only.
Identification,Ultraviolet Absorption á197Uñ—
Solution: 40µg per mL.
Medium: 0.1Nhydrochloric acid.
Absorptivity at 368nm,calculated on the dried and butyl alcohol-free basis,is not less than 83.0%and not more than 95.0%of that of the USP Chlortetracycline Hydrochloride RS,the potency of the Reference Standard being taken into account.
Crystallinity á695ñ: meets the requirements.
Loss on drying á731ñ— Dry it in vacuum at a pressure not exceeding 5mm of mercury at 60for 3hours:it loses not more than 2.0%of its weight.
Sulfate content— Transfer about 1g,accurately weighed,to a 250-mLbeaker,and dissolve in about 100mLof water.Neutralize the solution with 7.5Nammonium hydroxide to litmus paper,and warm.Filter,and wash the filter with warm water.Neutralize the filtrate with 6Nhydrochloric acid to litmus,and add an additional 4mLof 6Nhydrochloric acid.Heat the solution to boiling,and add,with constant stirring,sufficient boiling barium chloride TSto precipitate all of the sulfate.Add an additional 2mLof barium chloride TS,and digest on a steam bath for 1hour.Filter the mixture through ashless filter paper,transferring the residue quantitatively to the filter,and wash the residue with hot water until no precipitate is obtained when 1mLof silver nitrate TSis added to 5mLof washing.Transfer the paper containing the residue to a tared crucible.Char the paper,without burning,and ignite the crucible and its contents to constant weight.Perform a blank determination concurrently with the test specimen determination,and subtract the weight of residue obtained from that obtained in the test specimen determination to obtain the weight of residue attributable to the sulfate content of the specimen:not less than 15.0%is found,calculated on the dried and butyl alcohol-free basis.
Butyl alcohol—
Ceric ammonium nitrate solution— Dissolve 20g of ceric ammonium nitrate in 4Nnitric acid to obtain 100mLof solution.
Standard preparations— Transfer about 3g of butyl alcohol,accurately weighed,to a 1000-mLvolumetric flask containing 800mLof water,shake to dissolve,dilute with water to volume,and mix (Standard preparation 1).Transfer 10.0mLof Standard preparation 1and 1drop of dimethicone to a 50-mLdistilling flask equipped with a condenser and an extension that reaches into a collecting tube maintained in an ice-water bath.Distill slowly,and collect about 8mLof distillate.Warm the distillate to ambient temperature,and transfer with the aid of water to a 10-mLvolumetric flask.Dilute with water to volume,and mix (Standard preparation 2).
Test preparation— Transfer an accurately weighed specimen,equivalent to about 30mg of butyl alcohol,to a 50-mLdistilling flask equipped with a condenser and an extension that reaches into a collecting tube maintained in an ice bath.Add 25mLof water and 1drop of dimethicone to the distilling flask.Distill slowly,and collect about 8mLof the distillate.Warm the distillate to ambient temperature,and transfer with the aid of water to a 10-mLvolumetric flask.Dilute with water to volume,and mix.
Procedure— To four separate test tubes add,respectively,5.0mLof Standard preparation 1,5.0mLof Standard preparation 2,5.0mLof Test preparation,and 5.0mLof water to provide a blank.To each add 2.0mLof Ceric ammonium nitrate solution,and mix.Concomitantly determine the absorbances of the solutions from the Standard preparationsand the Test preparationat the wavelength of maximum absorbance at about 475nm,with a suitable spectrophotometer,using the blank to set the instrument to zero.In a suitable determination,the absorbance of the solution from Standard preparation 2is not less than 98.0%of the absorbance of the solution from Standard preparation 1.Calculate the percentage of butyl alcohol in the specimen taken by the formula:
1000(WS/WU)(AU/AS),
in which WSis the weight,in g,of butyl alcohol taken to prepare Standard preparation 1,WUis the weight,in mg,of specimen taken,and AUand ASare the absorbances of the solutions from the Test preparationand Standard preparation 2,respectively:not more than 15.0%is found.
Assay— Proceed with Chlortetracycline Bisulfate as directed for chlortetracycline under Antibiotics—Microbial Assays á81ñ.
Auxiliary Information— Staff Liaison:Ian DeVeau,Ph.D.,Senior Scientist
Expert Committee:(VET)Veterinary Drugs
USP28–NF23Page 458
Phone Number:1-301-816-8178