How to Write a GLP Study Plan
Define a non-clinical safety study so its data will hold up years later.
What a how-to is not
A how-to is SPEQ’s practitioner method, not a procedure. It does not replace your own SOP, it is not a validated approach, and the judgement calls in it belong to your quality unit.
A GLP study plan (protocol) defines the objective, design, and conduct of a non-clinical safety study before it begins — the document a Study Director owns and against which the whole study is judged. Under Good Laboratory Practice, the plan is the reference that makes a study reconstructable and its data defensible.
- 1
Define objective, design, and test system
State the objective, the study design, the test system and the justification for choosing it, in enough detail that the study could be reconstructed from the plan. Vagueness here is not resolved later: the plan is the reference against which the conduct is inspected, and a design described loosely permits a conduct that nobody can judge as compliant or otherwise.
- 2
Assign the Study Director and responsibilities
Name the Study Director, who holds single-point control of the conduct, interpretation and reporting of the whole study — including phases performed at other sites — and identify the principal investigators for those phases. The role is a person and an authority, not a title on a cover page, and an inspection will test whether that control was actually exercised.
- 3
Specify methods, endpoints, and acceptance
Specify the methods, the endpoints, the measurements and the acceptance criteria, along with the characterisation and stability information for the test and control items. A study is only as reconstructable as the knowledge of what was administered, and test-item characterisation is the detail most often found wanting years later.
- 4
Define records, retention, and archiving
Define what constitutes raw data for each measurement, where it will be held, and how it will be retained and archived. Ambiguity about which record is the original is the most common reconstructability failure in this discipline, and it is cheap to settle in the plan and nearly impossible to settle afterwards.
- 5
Approve before starting and control changes
Approve the plan before the study starts, and control changes to it through dated, signed amendments that record the reason. A change made to an in-progress study and documented afterwards as though it had been planned is the deviation that most damages a study’s credibility, because it puts the whole record in question rather than one measurement.
- !Starting work before the plan is approved, so early data has no controlling protocol.
- !Vague endpoints or methods that leave the conduct open to interpretation.
- !Deviations handled informally rather than documented against the plan.
- !Archiving that does not preserve the full study for later reconstruction.
How to Write a GLP Study Plan: frequently asked questions
Common questions on write a glp study plan.
Who owns the GLP study plan?
The Study Director — the single point of study control under GLP — owns the plan and is responsible for the technical conduct of the study and for the interpretation, analysis, documentation, and reporting of results.
What makes a study GLP vs GMP?
GLP governs non-clinical safety studies (e.g. toxicology) supporting a submission; the concern is that the study is credible and reconstructable. GMP governs how product is made and released. A QC release lab is GMP, not GLP, even though it is a laboratory.
Why must the plan be approved before the study starts?
Because the plan is the controlling reference for the entire study. Data generated before an approved plan exists has no defined design or acceptance criteria behind it, undermining the study’s integrity and reconstructability.