Riboflavin
;)
Riboflavine.
Riboflavine [83-88-5].
»Riboflavin contains not less than 98.0percent and not more than 102.0percent of C17H20N4O6,calculated on the dried basis.
Packaging and storage—
Preserve in tight,light-resistant containers.
Identification—
Asolution of 1mg in 100mLof water is pale greenish yellow by transmitted light,and has an intense yellowish green fluorescence which disappears upon the addition of mineral acids or alkalies.
Specific rotation á781Sñ:
between +56.5
and +59.5.
and +59.5.
Test solution:
5mg per mL,in hydrochloric acid.
Loss on drying á731ñ—
Dry about 500mg at 105for 2hours:it loses not more than 1.5%of its weight.
for 2hours:it loses not more than 1.5%of its weight.
Residue on ignition á281ñ:
not more than 0.3%.
Limit of lumiflavin—
Prepare alcohol-free chloroform just prior to use,as follows.Shake 20mLof chloroform gently but thoroughly with 20mLof water for 3minutes,draw off the chloroform layer,and wash twice more with 20-mLportions of water.Finally filter the chloroform through a dry filter paper,shake it for 5minutes with 5g of powdered anhydrous sodium sulfate,allow the mixture to stand for 2hours,and decant or filter the clear chloroform.Shake 25mg of Riboflavin with 10mLof the alcohol-free chloroform for 5minutes,and filter:the absorbance of the filtrate,determined in 1-cm cells at a wavelength of 440nm,with a suitable spectrophotometer,alcohol-free chloroform being used as the blank,does not exceed 0.025.
Organic volatile impurities,Method IVá467ñ:
meets the requirements.
Assay—
[NOTE—Conduct the entire procedure without exposure to direct sunlight.]Place about 50mg of Riboflavin,accurately weighed,in a 1000-mLvolumetric flask containing about 50mLof water.Add 5mLof 6Nacetic acid and sufficient water to make about 800mL.Heat on a steam bath,protected from light,with frequent agitation until dissolved.Cool to about 25,dilute with water to volume,and mix.Dilute this solution quantitatively and stepwise with water to bring it within the operating sensitivity of the fluorometer used.In the same manner prepare a standard solution to contain,in each mL,a quantity,accurately weighed,of USP Riboflavin RS,equivalent to that of the Riboflavin solution prepared as directed above,and measure the intensity of its fluorescence in a fluorometer at about 530nm.(An excitation wavelength of about 444nm is preferable.)Immediately after the reading,add to the solution about 10mg of sodium hydrosulfite,stirring with a glass rod until dissolved,and at once measure the fluorescence again.The difference between the two readings represents the intensity of the fluorescence due to the Standard.Similarly,measure the intensity of the fluorescence of the final solution of the Riboflavin being assayed at about 530nm,before and after the addition of sodium hydrosulfite.Calculate the quantity,in µg per mL,of C17H20N4O6in the final solution of Riboflavin taken by the formula:
,dilute with water to volume,and mix.Dilute this solution quantitatively and stepwise with water to bring it within the operating sensitivity of the fluorometer used.In the same manner prepare a standard solution to contain,in each mL,a quantity,accurately weighed,of USP Riboflavin RS,equivalent to that of the Riboflavin solution prepared as directed above,and measure the intensity of its fluorescence in a fluorometer at about 530nm.(An excitation wavelength of about 444nm is preferable.)Immediately after the reading,add to the solution about 10mg of sodium hydrosulfite,stirring with a glass rod until dissolved,and at once measure the fluorescence again.The difference between the two readings represents the intensity of the fluorescence due to the Standard.Similarly,measure the intensity of the fluorescence of the final solution of the Riboflavin being assayed at about 530nm,before and after the addition of sodium hydrosulfite.Calculate the quantity,in µg per mL,of C17H20N4O6in the final solution of Riboflavin taken by the formula:
C(IU/IS),
in which Cis the concentration,in µg per mL,of USP Riboflavin RSin the final solution of the Standard,and IUand ISare the corrected fluorescence values observed for the solutions of the Riboflavin and Standard,respectively.
Auxiliary Information—
Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(DSN)Dietary Supplements:Non-Botanicals
USP28–NF23Page 1723
Pharmacopeial Forum:Volume No.30(3)Page 929
Phone Number:1-301-816-8389