Writing a specification that means something

Under 21 CFR 111 the specification is not paperwork around the product. It is the thing the product is measured against, and without one there is nothing to be compliant with.

A specification is not a recipe

A recipe says what goes in. A specification says what the result must be, in numbers, with acceptance criteria that can be tested or verified.

The rule expects specifications for incoming components, for in-process points, and for the finished product, plus for packaging and labels.

What it has to contain

For components: identity, purity, strength and composition, plus limits on contaminants that matter for that material.

For the finished product: the label claim per serving, the manufacturing target including overage, acceptance ranges, moisture, appearance, and microbial and heavy metal limits where relevant.

For packaging: what the container and closure must be, because a moisture barrier is a specification rather than a preference for a hygroscopic powder.

Ranges, not targets

A single number is not a specification because nothing hits a single number. Write a range you can actually hold and that keeps the label claim true at both ends.

The range has to account for blend variability and for decline over shelf life, which is why the manufacturing target and the label claim are two different numbers.

Why the rule cares

Because without a written specification, "the batch was fine" is an opinion. With one, a batch either met the criteria or it did not, and the record shows which.

That is also why a specification you cannot test or verify against is not useful. Every line should have a method behind it, even if the method is a supplier certificate you have qualified rather than your own assay.

References