Yield calculation or reconciliation is the final manufacturing stage of pharmaceutical products. Percent yield is very important in the manufacture of pharmaceutical products to reduce the process loss.
Yield is usually measured in percentage and it is the ratio of input materials to output products or ratio of the theoretical quantity of the product to the actual quantity of the product and its formula is as follow,
%Yield = (Quantity of good product after manufacturing/Quantity of the product before manufacturing) × 100
or
%Yield = (Actual Quantity of Products ÷ Theoretical Quantity of Batch size) × 100
Example
In the pharmaceutical industry, a batch of tablets was manufactured having 100 kg standard batch size after dispensing and 99.0 kg after coating. Calculate the yield of the product.
By using above formula add values in it as follow
% Yield= (99÷100) × 100 = 99.0%
So, yield of the product is 99.0%.
Where,
% of Loss = 100 - Actual yield against Theoretical yield.
Yield Limit
Yield limit should be as tight possible to reduce process loss. But should not be impossible something (i.e., 99%-100%).
That's why it should be established from process optimization batch to process validation batches. Annual product review an appropriate option to set the optimum yield range/limit.
As per FDA 21 CFR § 211.103,
Actual yields and percentages of theoretical yield shall be determined at the conclusion of each appropriate phase of manufacturing, processing, packaging, or holding of the drug product.
Such calculations shall either be performed by one person and independently verified by a second person, or, if the yield is calculated by automated equipment under §211.68, be independently verified by one person.
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