Ergocalciferol Oral Solution
Ergocalciferol Oral Solution is a solution of Ergocalciferol in an edible vegetable oil, in Polysorbate 80, or in Propylene Glycol. It contains NLT 100.0% and NMT 120.0% of the labeled amount of vitamin D as ergocalciferol (C28H44O).
•  Procedure
Mobile phase: Chloroform containing alcohol as a preservative
Standard stock solution: 50 µg/mL of USP Ergocalciferol RS in chloroform. [Note—Prepare this solution fresh daily. ]
Standard solution A: 5 µg/mL of USP Ergocalciferol RS from the Standard stock solution in chloroform. [Note—Store this Standard solution A at a temperature not above 0. ]
Standard solution B: Transfer 5.0 mL of the Standard stock solution into a round-bottomed flask fitted with a reflux condenser. Displace the air with nitrogen, and reflux for 1 h in a water bath under a nitrogen atmosphere to obtain a solution containing ergocalciferol and pre-ergocalciferol. Cool, transfer, with the aid of several portions of chloroform, to a 50-mL volumetric flask, dilute with chloroform to volume, and mix.
Sample solution: Equivalent to 5 µg/mL of ergocalciferol from an accurately measured volume of Oral Solution in chloroform
Chromatographic system 
Mode: LC
Detector: UV 254 nm
Column: 4.6-mm × 25-cm; 5-µm packing L3
Flow rate: 1 mL/min
Injection size: 10–20 µL
System suitability 
Sample: Standard solution B
[Note—The relative retention times for pre-ergocalciferol and for ergocalciferol are 0.8 and 1.0, respectively. ]
Suitability requirements 
Resolution: NLT 1.0 between the pre-ergocalciferol peak and the ergocalciferol peak
Relative standard deviation: NMT 2.0%
Samples: Standard solution A, Standard solution B, and Sample solution
Ergocalciferol response factor 
Calculate the Ergocalciferol response factor, FD:
FD = CS/rS
CS== concentration of USP Ergocalciferol RS in the Standard solution A (µg/mL)
rS== peak response of ergocalciferol from Standard solution A
Pre-ergocalciferol response factor 
Calculate the concentration, C¢S, in µg/mL, of ergocalciferol in Standard solution B:
C¢S = FD × r¢S
FD== Ergocalciferol response factor
r¢S== peak area of ergocalciferol from Standard solution B
Calculate the concentration, C¢pre, in µg/mL, of pre-ergocalciferol:
C¢pre = CS C¢S
CS== concentration of USP Ergocalciferol RS in the Standard solution A (µg/mL)
C¢S== concentration of ergocalciferol in the Standard solution B (µg/mL)
Calculate the Pre-ergocalciferol response factor, Fpre:
Fpre = C¢pre/rp
C¢pre== concentration of pre-ergocalciferol (µg/mL)
rp== peak response of pre-ergocalciferol from Standard solution B
Vitamin D content 
Calculate the percentage of the labeled amount of vitamin D as ergocalciferol (C28H44O) in the portion of Oral Solution taken:
Result = {[(FD × rC) + (Fpre × rpre)]/CU} × 100
FD== ergocalciferol response factor
rC== peak area of ergocalciferol from the Sample solution
Fpre== response factor for pre-ergocalciferol
rpre== peak area of pre-ergocalciferol from the Sample solution
CU== nominal concentration of ergocalciferol in the Sample solution (µg/mL)
Acceptance criteria: 100.0%–120.0%
•  Packaging and Storage: Preserve in tight, light-resistant containers.
•  Labeling: Label the Oral Solution to indicate the concentration of ergocalciferol, in mg per dosage unit. The activity may be expressed also in terms of USP Units, on the basis that 40 USP Vitamin D Units = 1 µg.
•  USP Reference Standards 11
USP Ergocalciferol RS Click to View Structure
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/QuestionContactExpert Committee
MonographNatalia Davydova
Scientific Liaison
(DS2010) Monographs - Dietary Supplements
Reference StandardsRS Technical Services
USP35–NF30 Page 3065
Chromatographic Column— 
Chromatographic columns text is not derived from, and not part of, USP 35 or NF 30.