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Recovery, Repeatability & Reproducibility
Range ≤ 5 ppm 5 - 20
ppm
>20 - 1000
ppm
> 0.1% -
1% > 1%
%
Recovery
75 – 115 80 – 110 95 – 105 97 – 102 98 - 102
% RSD
r
≤ 12
≤ 8
≤ 5
≤ 4
≤ 2
%RSD
R
≤ 20
≤ 12
≤ 8
≤ 6
≤ 3
Reported as individual vitamin B
12
analogs
% Recovery, % RSDr and % RSD
R
shall be determined individually for
each claimed matrix.
Comments Submitted
COMMENT:
• Methylcobalamin is the least stable [form of B
12
] and will convert
to other forms in the presence of extraction solvents or matrix
components many unknown An assessment should be done to
,
.
demonstrate stability of extracts under extraction conditions, etc.
This is critical to measurement of methylcobalamin.
• Add stability of neat solutions to demonstrate lack of
interconversion to other B
12
species. Alternatively, add more
detail on matrix requirements for testing to include various types
of tablets, capsules, etc.
RESPONSE:
Suggest adding this statement to the Validation Guidance section,
“Because some vitamin B
12
forms are unstable, the stability of
vitamin B
12
in extracts should be demonstrated during analysis."