On 1 September 2026, a revised European Medicines Agency (EMA) guideline on the chemistry of active substances took effect. The EMA revised it to expand its sections on starting materials and to add recommendations on nitrosamines. [1] In the United States, Section 232 tariffs on patented drugs, their active pharmaceutical ingredients (APIs) and their key starting materials were set to apply to all other covered companies from 29 September 2026. [22][23] Check the current status of those tariffs before you act on this article.
Two rule sets now meet at one point in the supply chain: the key starting material (KSM). This article explains how regulators define a KSM, how to choose and qualify a KSM supplier, and how patent status now changes the cost of a sourcing decision. We cite primary sources wherever they exist. We label our own calculations as analysis. Data current to 8 October 2026.
The Short Answer: What Is a Key Starting Material in API Manufacture?
A key starting material (KSM) is the compound at which the regulatory description of API manufacture, and good manufacturing practice (GMP), begins. ICH and EMA documents use the term “starting material”. “KSM” is industry shorthand, and India’s production-linked incentive scheme uses it in its title. [1][7]
What does ICH Q11 say a starting material must be?
ICH Q11 says a starting material is a substance of defined chemical properties and structure. It says non-isolated intermediates are usually not appropriate starting materials. It also says the material is incorporated as a significant structural fragment into the drug substance. [3]
The 2026 EMA guideline repeats the structural-fragment test and the rule against non-isolated compounds. [1] ICH Q11 dates from 2012. [2]
Where does GMP start for an API?
ICH Q7 GMP applies to each branch of a convergent process from the first use of a starting material. [3] In the EU, the Q7 requirements sit in EU GMP Part II. [1] The 2026 EMA text says the use of starting materials marks the beginning of the process description and of manufacture under GMP. [1]
KSM, intermediate, reagent and drug intermediate: how do the terms differ?
Term
Plain meaning
Source
Starting material (KSM)
Isolated compound with a defined structure that supplies a significant structural fragment to the API. GMP starts here in the dossier.
[1][3]
Intermediate
A compound made after the starting material and before the API. Isolated intermediates need identity confirmation and control.
[1]
Reagent, solvent, catalyst
Materials that do not supply a significant structural fragment. They need specifications, but they are not starting materials.
[1][3]
Drug intermediate (DI)
Indian policy term used beside KSM in the production-linked incentive scheme for bulk drugs.
[7]
The Seven Findings That Matter
The EMA adopted its revised guideline on the chemistry of active substances on 16 February 2026. It took effect on 1 September 2026 and replaced EMA/454576/2016. [1]
The EMA text says multiple chemical transformation steps should typically separate the starting material from the API. It also says adding a starting-material manufacturing site needs a variation. [1]
FDA data from August 2019 show 230 API manufacturing facilities in China (13%) and 510 in the United States (28%) out of 1,788 for all regulated drugs. [5] We derive a total of 1,788 from the reported counts (analysis).
India’s Department of Pharmaceuticals says import dependence is 80 to 100% for some bulk drugs. Its incentive scheme covers 41 products with a Rs 6,940 crore outlay. [7][8]
Zhejiang Huahai approved a valsartan API process change in November 2011 that FDA later linked to NDMA formation. FDA estimated one additional cancer case per 8,000 people at the highest dose over four years. [10][14]
FDA rules say process patents and patents claiming intermediates must not be submitted for the Orange Book. A KSM route patent will not appear there. [20]
The Section 232 proclamation of 2 April 2026 sets a 100% base duty on patented drugs and on their APIs and key starting materials. Generic drugs and their ingredients are exempt. [22][23]
Methodology: What We Analyzed and What We Did Not
This article combines regulatory text, government data and legal summaries. It does not contain a patent-level dataset. All derived numbers come from figures printed in the cited sources.
What data did we use?
Included records
We used EMA and FDA guidance, the FDA warning-letter record for valsartan as reported by trade press, FDA supply-chain statistics, Indian government press notes, the text of 21 CFR 314.53, and Section 232 summaries from a law firm and SEC filings. We also used the public description of DrugPatentWatch coverage. [21]
Excluded records
We excluded unsourced market-size estimates and vendor marketing figures. We did not use any KSM price data. We found no primary source that gives global KSM volume by country, so we make no volume claim.
How did we calculate derived figures?
Percent-to-count conversion
FDA reported counts for China, the United States and the rest of the world, plus percentages by region. [5] We added the three counts to get 1,788. We multiplied each reported percentage by 1,788 to estimate counts for the EU, India and Canada. These estimates are approximate because FDA rounded its percentages.
Duty arithmetic
We multiplied a hypothetical customs value of USD 1,000,000 by each published Section 232 rate. The result shows the size of the duty. It is not a customs ruling, and other duties may apply.
Regulatory Timeline: From ICH Q7 to the 2026 EMA Guideline
Date
Event
Source
2000
ICH Q7 GMP for APIs issued (CPMP/ICH/4106/00)
[1]
November 2011
Zhejiang Huahai approves the valsartan API process change that later links to NDMA
[10]
2012
ICH Q11 issued
[2]
22 to 25 September 2014
CHMP adopts the EMA reflection paper on starting materials
[25]
3 July 2017
Revised reflection paper version dated; EMA’s copy now carries a “No longer valid” mark
[3]
July 2018
Valsartan recalls begin
[12]
28 September 2018
FDA places the Huahai site on import alert
[13]
Late November 2018
FDA warning letter sent to Huahai
[14]
2020 and February 2021
FDA nitrosamine guidance first issued, then revised (Revision 1)
[17]
4 September 2024
FDA issues Revision 2 of the nitrosamine guidance
[16]
16 February 2026
CHMP adopts the revised EMA guideline on the chemistry of active substances
[1]
2 April 2026
Proclamation 11020 imposes Section 232 tariffs on patented pharmaceuticals and APIs, including key starting materials
[23]
31 July 2026
Section 232 duties start for Annex III companies
[22][26]
1 September 2026
Revised EMA guideline takes effect
[1]
29 September 2026
Scheduled start for all other covered companies
[22]
One date needs a note. Several law-firm summaries date the proclamation 6 April 2026, the day of White House issuance or publication. SEC filings give 2 April 2026 as the signing date. [22][23]
How Do Regulators Judge a KSM Proposal?
How has the EMA changed its starting-material expectations since 2014?
2014 reflection paper
The CHMP adopted the reflection paper at its September 2014 meeting. [25] The paper’s problem statement said disagreements between applicants and assessors had become more frequent. It also said applicants increasingly proposed very short routes with complex custom-synthesized starting materials. [3]
2017 revision
The revised paper is dated 3 July 2017. It stated that “short synthetic routes will not normally be accepted.” [3] EMA’s PDF of this paper now carries a “No longer valid” mark. [3] Do not cite it as current guidance.
2026 guideline
The 2026 guideline replaces EMA/454576/2016 and absorbs the starting-material topic. It says the ICH Q11 requirements and the related Q&A apply to all active substances, whatever the development approach. [1] It requires a justified starting material, a flow chart of the synthesis before that material, and the names and addresses of its manufacturing sites. [1]
What does FDA expect for starting materials and master files?
ICH Q11 and the FDA Q&A
FDA publishes ICH Q11 and a companion question-and-answer document on the selection and justification of starting materials. [2][4] Use both. The Q&A gives worked reasoning that the main text does not.
Type II DMFs and letters of authorization
Drug master files (DMFs) are provided for in 21 CFR 314.420. A Type II DMF covers a drug substance, a drug substance intermediate, and material used in their preparation, or a drug product. [19] A KSM maker can file a Type II DMF. An applicant then needs a letter of authorization from the holder to refer to it. [19]
The eight-test KSM justification checklist
The table below organizes the EMA 2026 text into eight tests. The grouping is our own. The requirements come from the guideline. [1]
Test
Question an assessor asks
Evidence to hold
Source
1. Defined structure
Is the material isolated, with a defined structure?
Structure elucidation by current techniques (except Ph. Eur. active substances)
[1]
2. Structural fragment
Does it supply a significant structural fragment?
Scheme showing fragment in the API
[1][3]
3. Distance from the API
Do multiple chemical transformation steps separate it from the API?
Full route from KSM to API
[1]
4. Impurity fate
Can isomeric or mutagenic impurities carry through?
Fate and purge discussion; limits in the KSM specification
[1]
5. Pre-KSM route
How is the KSM made?
Flow chart with reagents, solvents and catalysts
[1]
6. Site information
Who makes it, and where?
Name and address of each KSM site
[1]
7. Nitrosamine risk
Do nitrosating agents or secondary or tertiary amines occur in the KSM synthesis?
Risk evaluation and control strategy
[1]
8. Origin
Is the material of animal, human or herbal origin?
TSE and viral safety data, or contaminant profile
[1]
Who Makes API and KSM Supply, and Where?
Where are API manufacturing facilities located?
FDA’s Center for Drug Evaluation and Research counted 1,788 API manufacturing facilities for all regulated drugs in August 2019. China had 230 of them (13%). The United States had 510 (28%). The rest of the world had 1,048 (59%). [5]
Region
Share of API facilities (reported)
Facilities (reported)
Facilities (derived, approximate)
United States
28%
510
Not needed
European Union
26%
Not reported
about 465
India
18%
Not reported
about 322
China
13%
230
Not needed
Other rest of world
13%
Not reported
about 232
Canada
2%
Not reported
about 36
Source for reported figures: FDA, August 2019. [5] Derived counts are our analysis (percentage multiplied by 1,788).
Analysis: China and India together held 31% of API facilities by count (13% plus 18%). The EU and the United States together held 54% (26% plus 28%). FDA also reported that the number of registered API facilities in China more than doubled between 2010 and 2019. [5]
Does facility count measure supply risk?
No. FDA said it cannot determine with any precision how much API China produces or how much enters the United States. [5] A site count says nothing about volume, product mix or single-source dependence. It also covers registered API sites, not KSM sites.
The 2019 data are also old. FDA’s FY2024 quality report lists 4,619 manufacturing sites in its site catalog and reports that 34% of India sites and 28% of China sites in the catalog were inspected. [6] That catalog covers all drug manufacturing, so do not compare it with the 2019 API count.
How dependent is India on imported bulk drugs and KSMs?
India’s Department of Pharmaceuticals states the dependence in direct terms.
“In some specific bulk drugs, the import dependence is 80 to 100%.” (Department of Pharmaceuticals, Government of India, 2021) [7]
The statement covers some bulk drugs, not all. The press note does not name the source countries in the passage we reviewed. [7]
What does India’s PLI scheme for KSMs cover?
The scheme supports domestic manufacture of 41 identified KSMs, drug intermediates and APIs. Its outlay is Rs 6,940 crore and its tenure runs from FY2020-21 to FY2029-30. [8] It sets minimum domestic value addition of 90% for fermentation-based products and 70% for chemical-synthesis products. [7] The department received 215 applications for 36 of the products. [7] A parliamentary reply from the department states that 48 projects have been approved. [9]
Analysis: Rs 6,940 crore divided by 41 products gives an average outlay of about Rs 169 crore per product. Actual support varies by product and segment, so treat this as a scale marker only.
A Taxonomy of KSM Sourcing Models (Original Framework)
The four models below are our own classification. No regulator uses these labels. We built them from the ICH Q11 distinction between commodity and custom-synthesized materials and from the EMA route options for intermediates covered by a certificate of suitability (CEP) or a master file. [1][3]
Model
Definition
Main sourcing risk (analysis)
Documents to hold
A. Commodity KSM
A chemical sold in a pre-existing non-pharmaceutical market as well as to API makers [3]
Grade-to-grade impurity variation. Supplier may not know the end use.
Evidence of the non-pharma market; impurity profile; incoming test method; any extra purification step [3]
B. Custom-synthesized KSM
A KSM made to order by a contract manufacturer. ICH Q11 does not treat it as commercially available. [3]
Single source. Route or solvent changes upstream.
Route flow chart, site names, specification, nitrosamine assessment [1]
C. Captive KSM
A KSM made by the API maker or an affiliate
Concentration at one site or one group
Same as B, under one quality system
D. Pharmacopoeial or approved-API intermediate
An intermediate that is itself a Ph. Eur. active substance with a valid CEP, or an API already documented in an authorized product [1]
Dependence on the CEP or master-file holder
CEP or ASMF reference; manufacturers listed in 3.2.S.2.1 and the QP declaration [1]
Which model needs the most regulatory documentation?
Analysis: Model B needs the most. The EMA asks for the pre-KSM route, the site names, a full specification and a nitrosamine evaluation. Model D can reduce the file, because a CEP can replace a process description for the covered intermediate. [1] The CEP does not remove the need to describe the later steps. [1]
Which model carries the most supply risk?
Analysis: Model B carries the most single-source risk, because the KSM is specific to your process and the EMA requires a variation to add a KSM site. [1] Model A carries the least switching cost but the most variation in impurity profile between suppliers. Test each incoming lot against the specification you filed.
Case Study: Valsartan, NDMA and a Process Change at Zhejiang Huahai
What happened, in dated steps?
November 2011: Zhejiang Huahai put a valsartan API process change into effect. The change included a solvent linked to the impurity. [10][11]
July 2018: Valsartan recalls began after NDMA was found in API supplied by Huahai. [12]
28 September 2018: FDA placed the Huahai facility on import alert. [13]
Late November 2018: FDA sent the company a warning letter after inspecting the site from 23 July to 3 August. [13][14]
What did FDA say about the process change?
FDA said Huahai made the change without evaluating its possible effect on API quality. [10] FDA also said the company failed to assess whether the new process could form mutagenic impurities. [11] The agency reported NDMA levels in Huahai valsartan that exceeded levels in valsartan from other firms. [11] A customer complaint about a nitrosamine finding years earlier had not triggered a proper investigation, according to the same report. [11]
How large was the estimated risk?
FDA estimated that if 8,000 people took the highest valsartan dose (320 mg) from the recalled batches every day for four years, one additional cancer case could occur over their lifetimes. [14]
What does the case teach about KSM sourcing?
Analysis: The failure here sat at the API maker. The same failure mode applies one step upstream. A KSM supplier can change a solvent, a quench step or a recovered material, and your API process will inherit the result. The EMA 2026 guideline lists a “lessons learnt” document on nitrosamines in sartan medicines among its references. [1] Build your supplier controls around that lesson: no upstream change without a documented impurity assessment.
How Do Nitrosamine Rules Change KSM Supplier Qualification?
What root causes does FDA list for nitrosamines in APIs?
FDA’s Revision 2 guidance (September 2024) names four root causes of small-molecule nitrosamine impurities in APIs. [15]
Vendor-sourced raw materials that contain nitrosamine impurities
Recovered solvents, reagents and catalysts
The quenching process
Lack of process optimization and control
Analysis: The first item is the KSM supplier question. If a vendor sells you a material, you inherit what is in it.
What does the 2026 EMA text require for starting materials?
The guideline requires the applicant to evaluate the risk that nitrosamines or their precursors form or carry over during starting-material synthesis. It names nitrosating agents and secondary or tertiary amines as examples. [1] If the evaluation finds a risk, the applicant should set a control in the starting-material specification or further downstream. The applicant can also look for another starting-material source that uses a different process. [1]
The text also asks the applicant to discuss isomeric and mutagenic impurities, including “cohort of concern” impurities, in the starting material. [1] The EMA revised the guideline to add recommendations on cohort-of-concern impurities, principally N-nitrosamines. [1]
What are the FDA dates?
FDA first issued its nitrosamine guidance in 2020 and revised it in February 2021. [17] Revision 2 was issued on 4 September 2024. [16] The agency recommended that manufacturers implement revised control measures by 1 August 2025. [18]
The KSM Supplier Qualification Playbook
This section is our recommended process. The steps are analysis, built on the cited regulatory requirements. They are not a regulatory checklist.
Step 1: Map the route before the KSM
Get the synthetic scheme that makes the KSM. The EMA requires a flow chart of the process before the starting material, with reagents, solvents and catalysts. [1] If the supplier refuses to share it, you cannot file the KSM as a Model B material in the EU.
Step 2: Classify the KSM
Place it in one of the four models above. A commodity claim needs evidence of a non-pharmaceutical market. [3] Do not rely on a catalog listing alone.
Step 3: Write a specification that controls impurities
The EMA expects complete specifications for starting materials, including limits for impurities. [1] Set limits from the fate of each impurity in your process, not from the supplier’s typical results. [1]
Step 4: Run the nitrosamine and mutagen assessment
Ask the supplier about nitrosating agents, amines, recovered solvents and quench steps. The EMA text asks for these items in the starting-material synthesis. [1] Recovered materials need their own specifications, because impurities can accumulate with repeated recovery. [1]
Step 5: Lock the change-control terms
What to put in the quality agreement
Notice before any change to route, solvent, reagent or site
Notice before any change to recovery or reprocessing practice
Right to review the impurity assessment for each change
Defined data to retain for each KSM lot
What to audit at the KSM site
Cleaning between campaigns, because cross-contamination between lines was one of the violations FDA cited at Huahai [12]
Change-control records for recent route or solvent changes
Recovery and reprocessing records
Test methods that can detect unexpected impurities
FDA’s Huahai findings included inadequate change control and a failure to evaluate analytical methods for unanticipated impurities. [11][12]
Step 6: Decide on a second source
A second KSM source reduces single-source risk. It also has a regulatory cost. In the EU, adding a KSM manufacturing site needs a variation. [1] In the United States, the cost depends on your application and any master files. Check it with your regulatory team before you sign a second supplier.
Do KSM and Process Patents Appear in the Orange Book?
What does 21 CFR 314.53(b)(1) exclude?
No. FDA lists drug substance, drug product and method-of-use patents. The regulation says process patents, packaging patents, metabolite patents and patents claiming intermediates must not be submitted. [20]
Analysis: A patent that claims your KSM route, or a KSM itself, will not appear in the Orange Book. Orange Book searches do not show route-level freedom-to-operate risk.
Where does DrugPatentWatch fit in KSM sourcing?
DrugPatentWatch lists active and expired patents in 134 countries, regulatory protections and exclusivities, API and finished-product suppliers, first generic entrants and US patent litigation. [21] We use it to find the drug’s patent families, expiry dates and known suppliers. We do not treat it as a substitute for the patent documents or a freedom-to-operate opinion.
How should you check a KSM route for patent risk?
Identify the drug patents and expiry dates
Start with the drug-level patents and exclusivities. They set the date when generic entry becomes possible, and they also affect tariff status (see below). Use the Orange Book and a source such as DrugPatentWatch for dates, then confirm with the patent record. [20][21]
Search process and intermediate claims at the patent offices
Search for claims on the KSM, the intermediates and the route. Search in each country where you make or sell. Read the claims. Do not rely on titles or abstracts.
Section 232 Tariffs: How Do They Reach KSMs in 2026?
What does Proclamation 11020 cover?
The President signed Proclamation 11020 on 2 April 2026. It concludes that imports of patented pharmaceuticals and associated APIs, including key starting materials, threaten US national security. [23] The 100% duty applies to patented articles subject to a valid, unexpired US patent that FDA lists in the Orange Book or Purple Book. It also applies to APIs and key starting materials for those articles. [22]
The duty started on 31 July 2026 for companies named in Annex III. It was scheduled to start on 29 September 2026 for all other companies. [22][23] US Customs and Border Protection issued implementing guidance on 30 July 2026. [26]
Which rates apply?
Case
Section 232 rate
Illustrative duty on USD 1,000,000 (analysis)
Patented drug, API or key starting material, base rate
100%
USD 1,000,000
Product of the EU, Japan, South Korea, Switzerland or Liechtenstein
15%
USD 150,000
Product of the United Kingdom
10%
USD 100,000
Company with an approved HHS onshore production plan (until 30 April 2030)
20%
USD 200,000
Orphan-designated drugs, nuclear medicines, plasma-derived therapies, fertility treatments, cell and gene therapies, antibody drug conjugates, CBRN countermeasures
0%
USD 0
Generic drugs and their ingredients; US-origin products
Exempt
USD 0
Products of 13 companies with MFN pricing agreements (until 20 January 2029)
No additional duty
USD 0
Rates and exemptions from the law-firm summary. [22] SEC filings from 2026 give the same overall range of 10% to 100% and also list US-origin APIs and key starting materials among the exemptions. [24]
Is a tariff “key starting material” the same as an ICH Q11 starting material?
Analysis: Do not assume so. The proclamation lists covered products by Harmonized Tariff Schedule number in its Annex I. [22] A customs code identifies a traded chemical. ICH Q11 identifies the point where an API’s regulatory process begins. A compound can be an ICH Q11 starting material and still fall outside the Annex I codes, or the reverse. Ask your customs broker to classify each KSM by code.
What happens to tariff exposure when the drug patent expires?
The generic exemption covers FDA-approved articles and their ingredients that are not subject to a valid, unexpired US patent and are off exclusivity. [22] Patent expiry dates therefore matter for KSM cost planning.
Scenario A: Orange Book patent still valid
Analysis: The KSM for a patented drug sits in the covered group unless an exemption or reduced rate applies. Origin and company status then set the rate. [22]
Scenario B: patents and exclusivity have expired
Analysis: If every listed patent and exclusivity has expired, the article should fall into the generic definition. The KSM for that article should then fall outside the duty. [22] Confirm the date with the Orange Book and with counsel, because a later patent listing could change the result.
Scenario C: a specialty exemption applies
Analysis: An orphan-designated drug, for example, carries a 0% rate for all approved indications. [22] Patent expiry would not change the duty for that product.
Scenario Analysis: Three Sourcing Responses
All three scenarios assume a patented small-molecule drug with a single non-US KSM source. The comparisons are qualitative. We found no public KSM cost data, so we give no cost figures.
Scenario 1: keep one non-US KSM source
You pay the duty rate for the source country while the drug patent stays valid. [22] You also keep single-source supply risk. This option makes sense when the patent expires soon, and when the origin carries a reduced rate such as 15% for the EU.
Scenario 2: add a US-origin KSM source
US-origin APIs and key starting materials are among the exempt categories. [24] You must add the site by variation in the EU and plan for the matching US filing work. [1] Expect qualification effort: route disclosure, specification, impurity assessment and lot data.
Scenario 3: seek an approved onshoring plan
Companies with approved onshore production plans with the HHS Secretary pay 20% until 30 April 2030. [22] This route applies at the company level, not the KSM level. It suits brand manufacturers with large US investment plans.
Scenario
Duty exposure while patent is valid
Regulatory effort
Supply risk
1. Keep one non-US source
Rate set by origin (for example 15% for the EU, 100% base)
None
Single source remains
2. Add US-origin source
Exempt category for the US-origin material
Variation and qualification work
Reduced
3. Onshoring plan
20% until 30 April 2030
Plan approval by HHS
Depends on the plan
Sources: [1][22][24]. The table is our analysis.
What This Means for Each Buyer Type
What this means for brand manufacturers
Your KSM duty exposure follows your patent term. Map each product’s Orange Book or Purple Book patent expiry to its KSM origin. [22] Treat any KSM process change as a regulatory and nitrosamine event, not a procurement event. [11][1]
What this means for generic entry
Generic drugs and their ingredients are exempt from the Section 232 duty. [22] Your KSM cost advantage is therefore not tariff-driven. Choose a source that you can document well, and check route patents that the Orange Book does not show. [20]
What this means for biosimilars
SEC filings list biosimilars among the exempt categories. [24] The EMA 2026 chemistry guideline does not apply to biological and biotechnological products. [1] The KSM concept in this article applies to chemical drug substances.
What this means for KSM makers and CDMOs
Expect customers to ask for your route flow chart, site details, impurity limits and nitrosamine assessment. [1] A Type II DMF for a KSM or intermediate gives customers a confidential way to refer to your data. [19] Expect change-control audits.
Key Takeaways
The revised EMA chemistry guideline took effect on 1 September 2026 and expands the starting-material requirements. [1]
The EMA’s 2017 reflection paper on starting materials is marked “No longer valid”. [3]
A justified KSM needs a defined structure, a significant structural fragment, a pre-KSM route and named sites. [1]
FDA counted 230 API facilities in China (13%) and 510 in the United States (28%) in August 2019. FDA cannot give volume. [5]
Nitrosamine evaluation now reaches into KSM synthesis. [1][15]
The Orange Book does not list process or intermediate patents. [20]
Section 232 duties tie KSM cost to the drug’s patent status, with generics exempt. [22]
Our four-model taxonomy and eight-test checklist are original organizing tools, not regulatory categories.
FAQ
Is a KSM the same as an API starting material?
Yes, in everyday use. ICH and EMA texts say “starting material”. “KSM” is industry shorthand and appears in India’s incentive scheme for KSMs, drug intermediates and APIs. [1][7]
Does a commodity chemical need a full justification as a starting material?
ICH Q11 says an applicant generally need not justify a commercially available chemical, which it defines as one sold as a commodity in a pre-existing non-pharmaceutical market. It says custom-synthesized chemicals are not commercially available. [3] EMA’s 2017 paper said a commercial-availability statement alone may not suffice, but that paper is no longer valid. [3] Keep the market evidence in the file anyway.
Do KSM patents appear in the Orange Book?
No. FDA rules bar the submission of patents that claim intermediates or processes. [20]
What is a Type II drug master file?
It is a confidential FDA submission for a drug substance, a drug substance intermediate, or material used in their preparation, or a drug product. An applicant refers to it with a letter of authorization from the holder. [19]
Does adding a second KSM manufacturer need a regulatory filing?
In the EU, yes. The 2026 EMA guideline says adding a starting-material manufacturing site needs approval by variation. [1]
Do nitrosamine rules apply to KSM makers?
They apply through your file. The EMA text asks you to evaluate nitrosamine formation and carry-over in starting-material synthesis. [1] FDA lists vendor-sourced raw materials as a root cause. [15]
Are generic drugs exposed to the Section 232 duty?
Generic drugs and their ingredients were exempt under the April 2026 proclamation and the 2026 CBP guidance we reviewed. [22][26] Trade policy changes. Check the current text.
Does India’s PLI scheme cover KSMs?
Yes. It covers 41 identified KSMs, drug intermediates and APIs, with a Rs 6,940 crore outlay running to FY2029-30. [8]
How much of India and China’s drug manufacturing base does FDA inspect?
FDA’s FY2024 quality report states that 34% of India sites and 28% of China sites in its site catalog were inspected. [6]
What is the cohort of concern?
It is the group of highly potent mutagenic carcinogens that ICH M7 treats with special limits. The EMA revised its chemistry guideline to add recommendations on these impurities, principally N-nitrosamines. [1]
References
European Medicines Agency. (2026, February 16). Guideline on the chemistry of active substances (EMA/CHMP/QWP/49484/2026). https://www.ema.europa.eu/documents/scientific-guideline/guideline-chemistry-active-substances_en.pdf
U.S. Food and Drug Administration. (2012). Q11 Development and manufacture of drug substances (chemical entities and biotechnological/biological entities): Guidance for industry. https://www.fda.gov/media/80909/download
European Medicines Agency. (2017, July 3). Reflection paper on the requirements for selection and justification of starting materials for the manufacture of chemical active substances (EMA/CHMP/CVMP/QWP/826771/2016 Corr. 1; marked “No longer valid”). https://www.ema.europa.eu/en/documents/scientific-guideline/reflection-paper-requirements-selection-and-justification-starting-materials-manufacture-chemical-active-substances_en.pdf
U.S. Food and Drug Administration. (n.d.). Q11 Questions and answers: Selection and justification of starting materials. https://fda.gov/media/103162/download
U.S. Food and Drug Administration. (2019, October 30). Safeguarding pharmaceutical supply chains in a global economy [Congressional testimony]. https://www.fda.gov/news-events/congressional-testimony/safeguarding-pharmaceutical-supply-chains-global-economy-10302019
U.S. Food and Drug Administration, Center for Drug Evaluation and Research. (2025). CDER’s FY2024 report on the state of pharmaceutical quality. https://www.fda.gov/media/188153/download
Department of Pharmaceuticals, Government of India. (2021, December 9). Press note: Approvals accorded under Production Linked Incentive (PLI) scheme for promotion of domestic manufacturing of critical Key Starting Materials (KSMs)/Drug Intermediates and Active Pharmaceutical Ingredients (APIs). https://pharma-dept.gov.in/sites/default/files/Press%20Note%20PLIBD_0_1.pdf
Manorama Yearbook. (2022, September 5). Scheme for promotion of bulk drug parks. https://www.manoramayearbook.in/current-affairs/india/2022/09/05/scheme-for-promotion-of-bulk-drug-parks.html
Department of Pharmaceuticals, Government of India. (n.d.). Reduction on import of APIs or bulk drugs [Parliamentary reply]. https://eparlib.nic.in/bitstream/123456789/2973994/1/AU50.pdf
BioPharma Dive. (2018). Chinese company at heart of valsartan investigation hit with warning letter. https://www.biopharmadive.com/news/chinese-company-at-heart-of-valsartan-investigation-hit-with-warning-letter/544236/
Fierce Pharma. (2018). China’s Zhejiang Huahai lambasted in FDA warning letter for putting profits ahead of safety. https://www.fiercepharma.com/manufacturing/china-s-zhejiang-huahai-lambasted-fda-warning-letter-for-putting-profits-ahead-safety
American Pharmaceutical Review. (2018). FDA warns API manufacturer involved in valsartan recall. https://www.americanpharmaceuticalreview.com/1315-News/356596-FDA-Warns-API-Manufacturer-Involved-In-Valsartan-Recall/
FDAnews. (2018). FDA blasts Zhejiang Huahai for failing to investigate contamination fully. https://fdanews.com/articles/189592-fda-blasts-zhejiang-huahai-for-failing-to-investigate-contamination-fully
WRAL. (2018). [News report on the FDA warning letter to Zhejiang Huahai Pharmaceutical]. https://www.wral.com/story/18060260/
U.S. Food and Drug Administration. (2024, September). Control of nitrosamine impurities in human drugs: Guidance for industry (Revision 2). https://fda.gov/media/141720/download
U.S. Food and Drug Administration. (n.d.). CDER nitrosamine impurity acceptable intake limits. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cder-nitrosamine-impurity-acceptable-intake-limits
Pharmaceutical Technology. (2024, October 23). What does the FDA’s recent update of the nitrosamine guidance convey? https://www.pharmtech.com/view/what-does-the-fda-s-recent-update-of-the-nitrosamine-guidance-convey-
FDA Law Blog. (2024, September 12). Revised final guidance on nitrosamines offers new recommendations for assessment and control. https://www.thefdalawblog.com/2024/09/revised-final-guidance-on-nitrosamines-offers-new-recommendations-for-assessment-and-control/
U.S. Food and Drug Administration. (n.d.). Drug master files: Guidelines. https://www.fda.gov/drugs/guidances-drugs/drug-master-files-guidelines
Legal Information Institute, Cornell Law School. (n.d.). 21 CFR 314.53: Submission of patent information. https://www.law.cornell.edu/cfr/text/21/314.53
Arandia, L. F., Jr., & Yu, C. K. (2026, April 13). Section 232 tariffs on pharmaceuticals: 100% duties on patented drugs and APIs starting July 31, 2026. Arnall Golden Gregory LLP. https://www.agg.com/news-insights/publications/section-232-tariffs-on-pharmaceuticals-100-duties-on-patented-drugs-and-apis-starting-july-31-2026/
Schrödinger, Inc. (2026). Form 10-Q for the quarterly period ended June 30, 2026. U.S. Securities and Exchange Commission. https://www.sec.gov/Archives/edgar/data/0001490978/000149097826000068/sdgr-20260630.htm
Hemab Therapeutics Holdings, Inc. (2026). Form 10-Q. U.S. Securities and Exchange Commission. https://www.sec.gov/Archives/edgar/data/0002114044/000119312526234386/d845757d10q.htm
European Medicines Agency. (2014, September 25). Guidelines and concept papers adopted during the CHMP meeting 22-25 September 2014 (EMA/CHMP/129673/2014). https://www.ema.europa.eu/cs/media/6791
C.H. Robinson. (2026, July 31). CBP implements new Section 232 tariffs on patented pharmaceuticals. https://www.chrobinson.com/en-us/resources/insights-and-advisories/client-advisories/2026q3/07-31-26-cbp-implements-section-232-tariffs-on-patented-pharmaceuticals/
