The eCTD Module 3 structure organizes quality and chemistry, manufacturing, and controls information. Its principal branches are 3.2.S for drug substance, 3.2.P for drug product, 3.2.A for appendices, 3.2.R for regional quality information, and 3.3 for literature references. Within S and P, separate locations cover manufacturing, controls, packaging, and stability.
Quick Answer
Identify what the document describes before choosing its section. Drug substance analytical procedures belong at 3.2.S.4.2; drug product procedures belong at 3.2.P.5.2. Their validation evidence has separate locations. Then check the electronic hierarchy for your authority and eCTD version: an ICH content heading is not automatically an available publishing node.
Use this reference to classify documents and resolve neighboring-section questions. For dossier preparation, ownership, and review, use the Module 3 quality guide. The five-module structure guide explains where quality sits in the wider application.
Scope: the content outline and electronic hierarchy
This lookup was checked on October 6, 2026 against:
- ICH M4Q(R1), Step 4 version dated September 12, 2002: the content outline and explanatory placement guidance.
- FDA's eCTD v3.2.2 comprehensive table of contents, version 2.3.5, February 18, 2025: Module 3 on printed pages 5–6.
- FDA's eCTD v4.0 comprehensive table of contents, version 2.2, February 2025: Module 3 on printed pages 5–6.
M4Q(R1) describes a registration-application format for drug substances and corresponding products within the Q6A and Q6B scopes, with applicability to other product categories requiring consideration by the relevant authority. It does not determine the complete evidence package for every product or development stage. A biotech subsection and a chemical-substance subsection can share a number while requiring different scientific content.
Do not substitute the proposed M4Q(R2) outline for this map. FDA's January 2026 M4Q(R2) guidance page labels it draft and not for implementation. Its linked draft contains the ICH Step 2 version endorsed May 14, 2025. Check for subsequent adoption and implementation instructions before changing a production template.
Three electronic-publishing distinctions
| Content item | FDA v3.2.2 hierarchy, version 2.3.5 | FDA v4.0 hierarchy, version 2.2 |
|---|---|---|
| S.1 general-information children | Lists S.1.1, S.1.2, and S.1.3 | Lists S.1 without those child headings |
| P.2 pharmaceutical-development children | Lists P.2 without P.2.1–P.2.6 | Lists P.2.1 through P.2.6 |
| 3.1 table of contents | No separate 3.1 heading in this electronic hierarchy | No separate 3.1 heading in this electronic hierarchy |
ICH's content outline includes 3.1 and more detailed P.2 subdivisions. Their existence does not authorize inventing electronic nodes. For example, P.2.2.1 can organize formulation-development text without becoming a separate FDA publishing location in either checked table. Conversely, the absence of S.1.2 from the v4.0 electronic hierarchy does not remove the substance-structure content from the dossier. Sources: the two FDA tables above and M4Q(R1), printed pages 5 and 12.
The tables below use shortened navigation labels. They cover the S and P content branches, including their key children; they are not XML templates or universal document requirements.
3.2.S: drug substance section lookup
Choose S when the subject is the drug substance. Record its identity and manufacturer in your working inventory so similar filenames from different suppliers do not become indistinguishable.
| Branch | Child locations and subjects | Placement cue |
|---|---|---|
| S.1 — General information | S.1.1 names; S.1.2 structure; S.1.3 general properties | Identity and basic characteristics. Apply the FDA v4.0 grouping distinction above |
| S.2 — Manufacture | S.2.1 manufacturers; S.2.2 process description and controls; S.2.3 materials; S.2.4 critical steps and intermediates; S.2.5 process validation/evaluation; S.2.6 process development | How the substance is made, controlled during manufacture, and developed |
| S.3 — Characterization | S.3.1 structure elucidation and other characteristics; S.3.2 impurities | Evidence establishing characteristics and impurity information |
| S.4 — Substance controls | S.4.1 specification; S.4.2 analytical procedures; S.4.3 procedure validation; S.4.4 batch analyses; S.4.5 specification justification | Distinguish the limit, the method, its validation, observed results, and the rationale |
| S.5 — Reference standards/materials | S.5 | Reference material used in substance testing |
| S.6 — Container closure system | S.6 | The substance's packaging system |
| S.7 — Stability | S.7.1 summary/conclusions; S.7.2 post-approval protocol/commitment; S.7.3 data | Separate interpretation, future commitment, and study results |
The full prefix is 3.2: S.4.3 means 3.2.S.4.3. These locations follow the FDA v3.2.2 table, printed page 5, with the S.1 difference checked against the v4.0 table.
Two nearby entries deserve care. S.1.2 describes structure; S.3.1 presents its elucidation and characterization. Likewise, S.2.6 discusses manufacturing development; S.2.2 describes the manufacturing process. A report's title may contain both subjects, so inspect its actual purpose and agree how its content will be organized before publishing.
3.2.P: drug product section lookup
Choose P for the drug product in its dosage form. A tablet specification is not a drug substance specification merely because the tablet contains the same named active ingredient.
| Branch | Child locations and subjects | Placement cue |
|---|---|---|
| P.1 — Description/composition | P.1 | Product, dosage form, and composition |
| P.2 — Pharmaceutical development | Detailed content map below | Why formulation, process, packaging, and related choices are appropriate |
| P.3 — Manufacture | P.3.1 manufacturers; P.3.2 batch formula; P.3.3 process description/controls; P.3.4 critical steps/intermediates; P.3.5 process validation/evaluation | Manufacturing the product rather than its active substance |
| P.4 — Excipient controls | P.4.1 specifications; P.4.2 analytical procedures; P.4.3 procedure validation; P.4.4 specification justification; P.4.5 human/animal-origin excipients; P.4.6 novel excipients | Excipient-specific information, with appendix cross-references where relevant |
| P.5 — Product controls | P.5.1 specifications; P.5.2 analytical procedures; P.5.3 procedure validation; P.5.4 batch analyses; P.5.5 impurity characterization; P.5.6 specification justification | The finished product's control package |
| P.6 — Reference standards/materials | P.6 | Product-testing reference material; consider information already provided under S.5 |
| P.7 — Container closure system | P.7 | Description and specifications of the product's packaging components |
| P.8 — Stability | P.8.1 summary/conclusions; P.8.2 post-approval protocol/commitment; P.8.3 data | Product stability, distinct from substance stability under S.7 |
Sources: FDA v3.2.2 hierarchy, printed pages 5–6, and FDA v4.0 hierarchy, printed pages 5–6. The child numbers for analytical validation differ between substance and product: S.4.3 versus P.5.3.
P.2 pharmaceutical-development content
| M4Q(R1) location | Content lookup |
|---|---|
| P.2.1 — Components | P.2.1.1 substance characteristics/compatibility; P.2.1.2 excipient selection and function |
| P.2.2 — Drug product | P.2.2.1 formulation development; P.2.2.2 overages; P.2.2.3 physicochemical/biological properties |
| P.2.3 — Manufacturing process development | Selection and development of the product process |
| P.2.4 — Container closure system | Suitability of the selected packaging system |
| P.2.5 — Microbiological attributes | Relevant microbiological-development considerations |
| P.2.6 — Compatibility | Product compatibility with reconstitution diluents or dosage devices |
This is an ICH content map, not a claim that every row or child is an electronic node. FDA v4.0 lists the six P.2 children; its checked hierarchy does not list the deeper P.2.1.1 or P.2.2.1 children. FDA v3.2.2 lists only P.2. See M4Q(R1), printed pages 12–13, and the FDA version table above.
A packaging drawing and a packaging-suitability discussion therefore answer different questions: P.7 describes the system, while P.2.4 addresses its suitability in the ICH content outline. For v3.2.2, publish that development discussion within the available P.2 location.
Appendices, regional quality information, and literature
| Location | Use and boundary |
|---|---|
| 3.2.A.1 | Facilities/equipment information. M4Q(R1)'s explanatory text addresses biotech facilities; do not turn it into a universal facility-file requirement |
| 3.2.A.2 | Adventitious-agent safety evaluation; coordinate relevant references from manufacturing and excipient sections |
| 3.2.A.3 | M4Q(R1) calls this “Excipients”; the checked FDA hierarchies label it “Novel excipients.” P.4.6 points to detailed novel-excipient information here |
| 3.2.R | Additional regional quality information. Determine content from the applicable authority's guidance |
| 3.3 | Key literature references supporting the quality material, where applicable |
These are defined locations, not spare folders for hard-to-classify documents. The regional-quality branch does not replace administrative Module 1. M4Q(R1)'s regional examples also do not establish that every example is required for every application. See M4Q(R1), printed pages 16–18, and FDA's Module 3 headings.
A quality-system record needs a separate relevance decision before classification. The quality-records submission guide and CAPA-to-eCTD guide address that handoff. A CAPA identifier alone does not determine a CTD destination.
Worked classification: a fictional tablet dossier
Assume a fictional product, Orion 10 mg tablets, containing substance OR-01. The following inventory is a teaching example, not an actual submission, scientific assessment, or executed software test. Locations identify the stated content; they do not certify the documents' completeness.
| Document and known context | Proposed content location | Why the tempting alternative is wrong |
|---|---|---|
| OR-01 substance release specification | 3.2.S.4.1 | P.5.1 would describe the product specification |
| Tablet assay analytical procedure | 3.2.P.5.2 | The test instructions are not their validation evidence |
| Validation report for that tablet assay | 3.2.P.5.3 | P.5.2 is the procedure location, not the validation-report location |
| OR-01 substance stability results | 3.2.S.7.3 | P.8.3 is for the product; S.7.2 is the post-approval protocol/commitment |
| Tablet post-approval stability protocol and commitment | 3.2.P.8.2 | It specifies the future program; it is not completed stability data |
| Tablet 12-month stability results | 3.2.P.8.3 | P.8.1 summarizes and interprets the stability package |
| Explanation of the selected tablet formulation | ICH content P.2.2.1; FDA v3.2.2 location P.2, v4.0 location P.2.2 | A detailed ICH content heading is not automatically a publishing node |
File named validation-final.pdf, with no subject identified | Unresolved | Could concern analytical or manufacturing validation, substance or product |
For the unresolved file, ask the owner to identify the material, procedure or process, report purpose, and approved version. Do not choose P.5.3 simply because the filename contains “validation.” Manufacturing-process validation has different locations, including S.2.5 and P.3.5.
The stability distinction is equally specific: the headings S.7.2 and P.8.2 concern post-approval protocols and commitments. A file called “stability protocol” without that context is insufficient for an automatic placement decision. Confirm its role in the stability package.
A reusable placement record
Copy this compact record into your document inventory before authoring or publishing:
| Field | Completed example |
|---|---|
| Authority, format, governing hierarchy | FDA; eCTD v4.0; comprehensive TOC version 2.2 |
| Product/substance context | Orion 10 mg tablets; finished product |
| Source identity and approved revision | Fictional report OR-VAL-004, revision 2 |
| Purpose established from contents | Validation evidence for the product assay |
| Content section and electronic destination | 3.2.P.5.3 / 3.2.P.5.3 |
| Linked material | Procedure OR-ANA-004 at P.5.2; specification at P.5.1 |
| Remaining decision | CMC reviewer to confirm report scope and source approval |
For your own record, replace every example value; an unknown authority, material, or purpose remains an open decision. Keep the source revision visible in document management, especially when coordinating regulatory content reuse.
After classification, check whether the Quality Overall Summary reflects the relevant source material. Handle changed source content through a regulatory impact assessment. Neither activity is completed merely by assigning a section number.
Apply the map in an authoring review
Bring one substance document, one product document, and one ambiguous file to an Assyro demo. Ask to inspect their source versions, proposed locations, and the resulting FDA v4.0 package through the eCTD authoring and validation workflow. Record which decisions still require your CMC reviewer.
Assyro's current format support is eCTD v4.0; v3.2.2 is not supported. EMA support remains on the roadmap. This reference covers regulatory structures beyond that product boundary; it does not claim Assyro automatically verifies every scientific distinction or supports every application type described here.
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Assyro Team
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