Supplement I to the Japanese Pharmacopoeia Fourteenth Edition

1364 General Tests, Processes and Apparatus
Supplement I, JP XIV
low. Generally, this test is intended for determining the content
of inorganic substances contained as impurities in an organic
substance.
The description, for example, ``not more than 0.10z (1
g),'' in a monograph, indicates that the mass of the residue is
not more than 1.0 mg per 1 g of the substance in the test in
which about 1 g of the substance is weighed accurately and
ignited by the procedure described below, and ``after
drying'' indicates that the sample is tested after being dried
under the conditions speciˆed in the test for Loss on drying.
Procedure
Previously ignite a crucible of platinum, quartz or porcelain
at 600 ± 509C for 30 minutes, and weigh accurately
after cooling in a desiccator (silica gel).
Take the sample of the amount directed in the monograph,
transfer into the ignited crucible, and weigh accurately.
When the quantity of the sample to be taken is indicated
in a volume, pipet exactly the amount directed in the monograph
and transfer into the above crucible. When directed as
``after evaporating,'' heat properly to evaporate the solution.
Moisten the sample with a small amount of sulfuric acid,
usually 1 mL, then heat slowly at a temperature as low as
practicable until the sample is completely carbonized, and
cool. Moisten again with a small amount of sulfuric acid,
heat gently until white fumes are no longer evolved, and ignite
at 600 ± 509C until the residue is completely incinerated.
Proceed with care to not burn with a ‰ame. Cool the
crucible in a desiccator (silica gel), and reweigh accurately to
calculate the amount of the residue.
When the amount of the residue obtained above exceeds
the limit speciˆed in the monograph, unless otherwise speci-
ˆed, ignite repeatedly to constant mass.
Change to read:
66. Vitamin A Assay
The Vitamin A Assay is a method to determine vitamin A
in Retinol Acetate, Retinol Palmitate, Vitamin A Oil, Cod
Liver Oil and other preparations. Method 1 is for the assay
of synthetic vitamin A esters, using the ultraviolet-visible
spectrophotometry (Method 1-1) or the liquid chromatography
(Method 1-2). Method 2 is for the assay of vitamin
A of natural origin, containing many geometrical
isomers, using the ultraviolet-visible spectrophotometry to
determine vitamin A as vitamin A alcohol obtained by
saponiˆcation in an alkaline solution and extraction.
One Vitamin A Unit (equal to 1 vitamin A I.U.) is equivalent
to 0.300 mg of vitamin A (all-trans vitamin A alcohol).
Procedure
All procedures should be carried out quickly and care
should be taken as far as possible to avoid exposure to light,
air, oxidants, oxidizing catalysts (e.g. copper, iron), acids
and heat. If necessary, light-resistant vessels may be used.
Generally, for synthetic vitamin A esters apply Method
1-1 or Method 1-2, but if the assay conditions required for
Method 1-1 are not suitable, apply Method 2.
Method 1-1
Weigh accurately about 0.1 g of the sample, and dissolve
in 2-propanol for vitamin A assay to make exactly 50 mL.
Dilute this solution with 2-propanol for vitamin A assay to
make a solution so that each mL contains 10 to 15 vitamin A
Units, and use this solution as the sample solution. Determine
the absorption spectrum of the sample solution between
220 nm and 400 nm as directed under the Ultravioletvisible
Spectrophotometry to obtain the wavelength of the
maximum absorption and the absorbances at 300 nm, 310
nm, 320 nm, 326 nm, 330 nm, 340 nm and 350 nm. When
the maximum absorption lies between 325 nm and 328 nm,
and the ratios, A li /A 326 , of each absorbance, A li ,at300nm,
310 nm, 320 nm, 330 nm, 340 nm and 350 nm to the absorbance,
A 326 , at 326 nm are within the range of ±0.030 of the
values in the Table, the potency of vitamin A in Units per g
of the sample is calculated from the following equation.
UnitsofvitaminAin1g= A 326
W × V
100 × 1900
A 326 : Absorbance at 326 nm
V: Total volume (mL) of the sample solution
W: Amount (g) of sample in V mL of the sample solution
1900: Conversion factor from speciˆc absorbance of
retinol ester to IU (Unit/g)
This method is applied to drugs or preparations containing
vitamin A esters (retinol acetate or retinol palmitate) as
the main component. However, when the wavelength of
maximum absorption does not lie between 325 nm and 328
nm, or when the absorbance ratio A li /A 326 is not within the
range of ±0.030 of the values in the Table, apply Method 2.
Table Absorbance Ratio, A li /A 326 , of retinol acetate and
retinol palmitate
l i (nm)
300
310
320
330
340
350
A li /A 326
Retinol acetate Retinol palmitate
0.578
0.815
0.948
0.972
0.786
0.523
0.590
0.825
0.950
0.981
0.795
0.527
Method 1-2
Proceed with an appropriate amount of sample as directed
under the Liquid Chromatography.
For the assay of retinol acetate and retinol palmitate use
Retinol Acetate Reference Standard and Retinol Palmitate
Reference Standard, respectively, and ˆx appropriately the
operating procedure, the operating conditions and the system
suitability based on the characteristics of the substance
to be tested and the species and amount of coexisting substances.