Purpose
This SOP describes
the procedure for rounding off the digits while calculating and preparing
analytical reports.
Scope
This procedure is
applicable for Research and Development
Centre at “ABC Limited”.
Procedure:
- Analytical results observed in the laboratory (calculated from experimental- Measurements) are compared with stated limits to determine whether there is Conformance with Compendial assay or test requirements.
- The observed or calculated values for usually shall contain more significant figures than there are in the stated limit and an observed or calculated reporting result is to be rounded off to the number of places that is in agreement with the limit.
- Limits which are fixed numbers are not rounded.
- When rounding off is required, consider only one digit in the decimal place to the right of the last place in the limit expression. If this digit is smaller than 5, it is eliminated and the preceding digit is unchanged.
- If this digit is greater than 5, it is eliminated and the preceding digit is increased by one. If this digit equals 5, the 5 is eliminated and the preceding digit is increased by one. Following are some examples:
The
final reporting shall be done only up to the digit as given in limit:
Example:
If limit is - 95.0% to 110.0%
Observed value
is - 95.0256%
Correct rounded
value - 95.0% (only one digit after
decimal)
Single
next digit from the limit, shall be considered for rounding:
Example:
If limit is -
90.0% to 110.0%
Observed value
is - 98.0592%
Correct rounded
value -
98.1%
First
the calculation shall be done in mg/dosage form and finally in %.
In
case of reporting is to be done in mg/dosage form, Do reporting up to two
digits after decimal.
Example:
If label claim is
12.5mg/tablet, and limit 95.0% to105.0%.
Calculated
value: 12.4862 mg /tablet.
Rounded
value: 12.49 mg/tablet, and in % : 99.9 %
If
the observed value is less than 0.5%, the reporting shall be done in two digits
after decimal (generally in case of RS testing).
Example: If limit is NMT 0.5%
Observed value:
0.4569%
Rounded value is
0.46 %
If
the observed value is less than 0.1%, the reporting shall be done in two digits
after decimal (generally in case of RS testing).
Example: If limit is NMT
0.1%
Observed value is
0.04456%
Rounded value is
0.04%
In case of dissolution the reporting shall be
done up to one digit after decimal:
Example: If limit NLT 80%
Observed value:
85.062%
Rounded value:
85.1%
In
case of working standard preparation the final reporting shall be done up to
two digits after decimal (for both mg and %)
If
the result found in near limit or less then limit , then we follow the below
table,
|
Illustration of
rounding numerical values for comparison with requirements
|
|||
|
Compendia
requirement
|
Unrounded value
|
Rounded results
|
Conforms
|
|
Assay limit ≥ 98.0%
|
97.96%
|
98.0%
|
Yes
|
|
97.92%
|
97.9%
|
No
|
|
|
97.95%
|
98.0%
|
Yes
|
|
|
Assay limit ≤ 101.5%
|
101.55%
|
101.6%
|
No
|
|
101.46%
|
101.5%
|
Yes
|
|
|
101.45%
|
101.5%
|
Yes
|
|
|
Limit test ≤ 0.02%
|
0.025%
|
0.03%
|
No
|
|
0.015%
|
0.02%
|
Yes
|
|
|
0.027%
|
0.03%
|
No
|
|
|
Limit test ≤ 3 ppm
|
3.5 ppm
|
4 ppm
|
No
|
|
2.5 ppm
|
3 ppm
|
Yes
|
|
|
2.8 ppm
|
3 ppm
|
Yes
|
|
