Chlorothiazide Sodium for Injection
C7H5ClN3NaO4S2 317.71

2H-1,2,4-Benzothiadiazine-7-sulfonamide,6-chloro-,1,1-dioxide,monosodium salt.
6-Chloro-2H-1,2,4-benzothiadiazine-7-sulfonamide 1,1-dioxide monosodium salt [7085-44-1].
»Chlorothiazide Sodium for Injection is a sterile,freeze-dried mixture of Chlorothiazide Sodium (prepared by the neutralization of Chlorothiazide with the aid of Sodium Hydroxide)and Mannitol.It contains chlorothiazide sodium (C7H5ClN3NaO4S2)equivalent to not less than 93.0percent and not more than 107.0percent of the labeled amount of chlorothiazide (C7H6ClN3O4S2).
Packaging and storage— Preserve in Containers for Sterile Solidsas described under Injections á1ñ.
Constituted solution— At the time of use,it meets the requirements for Constituted Solutionsunder Injections á1ñ.
Identification, Ultraviolet Absorption á197Uñ—
Solution: 10µg per mL.
Medium: sodium hydroxide solution (1in 250).
Bacterial endotoxins á85ñ— It contains not more than 0.3USP Endotoxin Unit per mg of chlorothiazide sodium.
Uniformity of dosage units á905ñ: meets the requirements.
pHá791ñ: between 9.2and 10.0,in a solution prepared as directed in the labeling.
Other requirements— It meets the requirements under Injections á1ñ.
Assay— Transfer an accurately weighed portion of Chlorothiazide Sodium for Injection,equivalent to about 500mg of chlorothiazide,to a 1000-mLvolumetric flask,add sodium hydroxide solution (1in 250)to volume,and mix.Transfer 5.0mLof this solution to a 250-mLvolumetric flask,dilute with sodium hydroxide solution (1in 250)to volume,and mix.Concomitantly determine the absorbances of this solution and a Standard solution of USP Chlorothiazide RSin the same medium having a known concentration of about 10µg per mLin 1-cm cells at the wavelength of maximum absorbance at about 292nm,with a suitable spectrophotometer,using sodium hydroxide solution (1in 250)as the blank.Calculate the quantity,in mg,of C7H6ClN3O4S2in the portion of Chlorothiazide Sodium for Injection taken by the formula:
50C(AU/AS),
in which Cis the concentration,in µg per mL,of USP Chlorothiazide RSin the Standard solution,and AUand ASare the absorbances of the assay solution and the Standard solution,respectively.
Auxiliary Information— Staff Liaison:Andrzej Wilk,Ph.D.,Senior Scientific Associate
Expert Committee:(PA5)Pharmaceutical Analysis 5
USP28–NF23Page 447
Pharmacopeial Forum:Volume No.28(1)Page 51
Phone Number:1-301-816-8305