Caffeine and Sodium Benzoate Injection
»Caffeine and Sodium Benzoate Injection is a sterile solution containing equal amounts of Caffeine and Sodium Benzoate in Water for Injection.It contains not less than 90.0percent and not more than 110.0percent of the labeled amounts of anhydrous caffeine (C8H10N4O2)and sodium benzoate (C7H5NaO2).
Packaging and storage— Preserve in single-dose containers,preferably of Type Iglass.
Identification—
A: The caffeine obtained in the Assay for caffeineherein responds to Identificationtest Aunder Caffeine.
B: Dip the end of a platinum wire into a portion of Injection,and then introduce it into a nonluminous flame:the flame is colored intensely yellow.
C: To about 0.5mLof Injection add a few drops of ferric chloride TS:a salmon-colored precipitate is formed.To another portion of Injection add 3Nhydrochloric acid:a white precipitate is formed.
Bacterial endotoxins á85ñ— It contains not more than 0.7USP Endotoxin Unit per mg of caffeine and sodium benzoate,based on the total,in mg,of the labeled amounts.
pHá791ñ: between 6.5and 8.5.
Other requirements— It meets the requirements under Injections á1ñ.
Assay for caffeine— Measure accurately a volume of Injection,equivalent to about 250mg each of caffeine and sodium benzoate,transfer it completely with the aid of about 5mLof water to a small separator,add 1drop of phenolphthalein TS,and add 0.1Nsodium hydroxide,dropwise,until a permanent pink color is just produced.Shake the mixture with three or more 20-mLportions of chloroform to effect complete extraction of the caffeine,passing each chloroform extract through a small filter previously moistened with chloroform into a tared dish.(Retain the water layer for the Assay for sodium benzoate.)Wash the stem of the separator,the filter,and the funnel with 10mLof hot chloroform,adding the washings to the dish.Evaporate the combined chloroform solutions on a steam bath,adding 2mLof alcohol just before the last trace of chloroform is expelled.Complete the evaporation of the solvent,dry the residue,consisting of C8H10N4O2,at 80for 4hours,cool,and weigh.
Assay for sodium benzoate— To the water layer obtained in the Assay for caffeineadd 75mLof ether and 5drops of methyl orange TS.Titrate with 0.1Nhydrochloric acid VS,mixing the liquids by vigorous shaking,until a permanent pink color is produced in the water layer.Each mLof 0.1Nhydrochloric acid is equivalent to 14.41mg of C7H5NaO2.
Auxiliary Information— Staff Liaison:Salvador C.Salado,M.S.,Scientist and Latin American Liaison
Expert Committee:(PA3)Pharmaceutical Analysis 3
USP28–NF23Page 314
Phone Number:1-301-816-8165