Forced Degradation & Photostability

1. What this module does

For each stress condition you enter the assay (as % of the unstressed control), the total degradation products, the main degradant, the peak purity and the lowest resolution. The tool calculates the degradation and mass balance, checks the 5–20% target, and checks that the required stresses are covered.

For photostability you enter the exposure achieved and the initial, exposed and dark control results for each presentation. The tool checks the ICH Q1B minimum exposure and finds the presentations that protect the product.

What you get

• Forced degradation report (3.2.S.3.2 or 3.2.P.5.5) with a degradation chart.
• Photostability report (3.2.S.7.3 or 3.2.P.8.3) with the labelling conclusion.

2. Before you start

Have these ready. You can still start with the example data and replace it piece by piece.

• Stress conditions and results for one representative batch.
• Peak purity and resolution from the stability-indicating procedure.
• Degradation pathways and structures.
• Photostability exposure and results for each presentation.

3. Step by step with the example

Open the tool at app.cmcfy.com/app/forced-degradation.html. The example is loaded when the page opens, so every panel already has realistic data. Follow the steps to see how it works, then replace the example with your own data.

1. Describe the study

   Choose the product type (small molecule or biological), the material, and name the procedure being shown to be stability-indicating.

   

2. Enter stress and photostability results

   One row per stress condition. For photostability, one row per presentation and test, with the maximum change allowed.

3. Read the result

   The headline sums it up: "6 stress conditions · stability-indicating · light protection needed". The chart shows the degradation of each condition against the 5–20% band.

   

4. Resolve alerts and download

   A peak purity failure is critical. Missing stresses, low resolution, mass balance outside 95–105%, over-stressing, too little light exposure, no dark control and labelling are flagged. Then preview and download both reports.

   

4. Field reference

Every input in the tool, panel by panel. Tables accept rows pasted straight from Excel, comma-separated text, or a loaded file; check the columns after loading a file. Fields marked “when it applies” appear only for the choices that need them.

1 · Study

2 · Stress results

One row per condition. Assay as % of the unstressed control; total degradation products in % area. Peak purity: pass or fail. Resolution: lowest between the main peak and any degradant.

3 · Photostability (ICH Q1B)

5. Checks and alerts

Calculations and pass/fail outcomes always come from fixed rules, never from AI. The tool checks:

• Small molecules: acid, base, oxidation, heat and light. Biologics: high temperature, oxidation, light, agitation, freeze–thaw and pH.
• Peak purity (critical) and resolution of at least 1.5.
• Mass balance and degradation targets.
• ICH Q1B: 1.2 million lux h, 200 W h/m², dark control, presentations.

How to resolve alerts

• Critical alerts block the download and must be fixed in the data. A failing result can instead be linked to an investigation: type the investigation reference and outcome and press Record.
• Major alerts block the download until you fix them or type a justification and press Accept justification.
• Minor alerts do not block anything. They are listed in the documents so the reviewer sees them.
• Some alerts have an Apply fix button that makes the change for you. Reopen undoes a justification.

Narratives

This module writes: Stress testing discussion; Photostability conclusion. Each narrative is written by fixed rules from your data. You can edit it in the box. Rewrite with AI (where your plan includes AI) rewrites it in regulatory style; every number in the text is checked against your data, and a number that does not match is flagged under the box and blocks the download until you correct it. Reset to rule-based text brings back the original.

6. Preview, gap review and download

1. Press Preview next to a section, or Preview and download all. The document opens in a preview window, exactly as the Word file will read.
2. The left side lists the review, run on your device: gaps in the data (missing values, open alerts), gaps in the report (missing content the guidance expects, placeholders such as [site] or TBD left in the text) and, if you load the approved protocol under Compare with the protocol, differences from the protocol (requirements, criteria, batches or time points it plans that the report does not show).
3. Click a finding to jump to the place in the preview. Fix it in the tool, then preview again.
4. Optional AI review: a second read for contradictions, claims without data and vague wording. The report text is sent to Claude only when you press it, and only where your plan includes AI. Check every AI finding; AI can be wrong.
5. Press Download Word (.docx) or Download PDF. With several documents open, All as Word (.zip) and All as PDF (.zip) download the set. The download buttons stay disabled while a blocking alert is open; the preview still works.

Documents this module produces

Use Save project to keep your work as a file on your computer, and Open project to continue later. Start blank clears every field; Load example brings the example back. Nothing is stored on CMCfy servers.

7. US and EU submissions

Both regions follow ICH Q1A(R2), Q1B and Q2(R2) (Q5C for biologics). EU storage statements follow CPMP/QWP/609/96 Rev 2.

8. Working with other modules

• Degradants feed the impurity assessment in the Impurity & Risk Studio.
• The specificity result supports the Method Validation Studio.
• Long-term data go in the Stability Studio.

9. Common pitfalls

• Over-stressing until secondary degradants appear.
• Concluding stability-indicating without peak purity.

10. Practice exercises

Each exercise starts from the example (press Load example to reset). We run these on every update of this guide, so the result you see should match.

1. Fail peak purity under oxidation

   Change the peak purity of the oxidation condition to fail.

   Expected resultThe headline says specificity is not shown.