Vitamin A
»Vitamin Acontains a suitable form of retinol (C20H30O;vitamin Aalcohol)and possesses vitamin Aactivity equivalent to not less than 95.0percent of that declared on the label.It may consist of retinol or esters of retinol formed from edible fatty acids,principally acetic and palmitic acids.It may be diluted with edible oils;or it may be incorporated in solid,edible carriers or excipients;and it may contain suitable antimicrobial agents,dispersants,and antioxidants.
Packaging and storage— Preserve in tight containers,preferably under an atmosphere of an inert gas,protected from light.
Labeling— Label it to indicate the form in which the vitamin is present,and to indicate the presence of any antimicrobial agent,dispersant,antioxidant,or other added substance,and to indicate the vitamin Aactivity in terms of the equivalent amount of retinol,in mg per g.The vitamin Aactivity may be stated also in USP Units,on the basis that 1USP Vitamin A Unit equals the biological activity of 0.3µg of the all-transisomer of retinol.
Identification—
A: To 1mLof a chloroform solution of it containing the equivalent of approximately 6µg of retinol,add 10mLof antimony trichloride TS:a transient blue color appears at once.
B:Thin-Layer Chromatographic Identification Test á201ñ—
Test solution—
FOR LIQUID FORM OF VITAMIN A— Dissolve a volume equivalent to about 15,000USP Units in chloroform to obtain 10mLof solution.
FOR SOLID FORM OF VITAMIN A— Weigh a quantity equivalent to about 15,000USP Units,place in a separator,add 75mLof water,shake vigorously for 1minute,extract with 10mLof chloroform by shaking for 1minute,and centrifuge to clarify the chloroform extract.
Standard solution— Dissolve the contents of 1ampul of USP Vitamin A RSin chloroform to obtain 25.0mL.
Developing solvent system: a mixture of cyclohexane and ether (4:1).
Procedure— Apply at the starting point of the chromatogram 0.015mLof the Standard solutionand 0.01mLof the Test solution,and proceed as directed for Thin-Layer Chromatography underChromatography á621ñ.Allow the solvent front to move a distance of 10cm,remove the plate,and air-dry.Spray with phosphomolybdic acid TS:the blue-green spot formed is indicative of the presence of retinol.The approximate RFvalues of the predominant spots,corresponding to the different forms of retinol,are 0.1for the alcohol form,0.45for the acetate,and 0.7for the palmitate.
Absorbance ratio— The ratio of the corrected absorbance (A325)to the observed absorbance A325determined as directed under Vitamin A Assay á571ñis not less than 0.85.
Assay— Using a suitable quantity of Vitamin A,accurately weighed,proceed as directed under Vitamin A Assay á571ñ.
Auxiliary Information— Staff Liaison:Lawrence Evans,III,Ph.D.,Scientist
Expert Committee:(DSN)Dietary Supplements:Non-Botanicals
USP28–NF23Page 2028
Pharmacopeial Forum:Volume No.29(6)Page 2004
Phone Number:1-301-816-8389