Irinotecan HCl CAS 97682-44-5 | Bulk Anhydrous API Moisture Control
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Content
Shaanxi Sunrise Pharmaceutical Co., Ltd.
Upstream Botanical Extraction · Bulk API Synthesis · QA‑Driven Supply
Technical QA & Upstream Sourcing Monograph — CAS 97682‑44‑5 Focus
Navigating the Hygroscopic Trap of CAS 97682‑44‑5:
Why Bulk Anhydrous Irinotecan Hydrochloride Demands Rigorous Moisture Control
Introduction
Irinotecan hydrochloride belongs to a class of semisynthetic camptothecin analogues that inhibit topoisomerase I. The enzyme normally relieves torsional strain as the DNA double helix unwinds ahead of the replication fork; when irinotecan is present, it first needs to be activated. Hepatic and plasma carboxylesterases convert the prodrug into SN‑38, and SN‑38 is the species that actually binds the topoisomerase I–DNA cleavage complex. Once stabilized, the complex traps the strand break and the cell is pushed toward apoptosis. This is the reason irinotecan shows up so often in combination regimens for metastatic colorectal cancer, and it is also used, though less frequently, in small‑cell lung and gastric cancers.
In bulk API trading the situation is less straightforward than it looks in the pharmacology textbooks. The same hydrochloride salt can be ordered under two different registry numbers. CAS 97682‑44‑5 covers the salt as a general entity, whatever its state of hydration; CAS 136572‑09‑3 refers specifically to the trihydrate that actually goes into parenteral products. We have written this monograph for formulation researchers and QA auditors, many of whom have been burned by treating these two numbers as interchangeable. Getting the distinction right, and keeping moisture under control while the anhydrous intermediate sits in a warehouse, has a direct bearing on formulation success, method validation, and how cleanly a submission clears EP/USP review.
About the Manufacturer
Shaanxi Sunrise Pharmaceutical Co., Ltd. runs an upstream botanical extraction line and a bulk API synthesis plant; we do not make finished dosage forms. This monograph on Irinotecan Hydrochloride Salt / Anhydrous Form (CAS: 97682‑44‑5) is aimed at formulation researchers and QA auditors. We supply bulk primary raw materials only — no compounding, no packaging into retail vials, no distribution of finished parenteral injections. Readers can take the document at face value as a technical reference on raw‑material quality rather than as a pitch for a finished product.
General Salt Definition • CAS 97682‑44‑5
Anyone who has worked through legacy chemistry literature or scrolled through a broad chemical inventory has run across CAS 97682‑44‑5. It is not a precise designation. Unlike the trihydrate number, it has historically served as an umbrella for irinotecan hydrochloride in just about any hydration state — partially dried amorphous material, or batches carrying different amounts of crystal water depending on how they were dried and how long they sat on a shelf.
We live with this ambiguity on our own drying floor. If a raw material is bought and sold under a loose CAS definition, and no one bothers to pin down the hydration state, formulation problems are basically guaranteed. Why does anhydrous material behave like a moisture trap in a humid warehouse? Why does the powder seize up and cake? And what does it take to convert a vague registry entry into a specification that a QA department can actually defend? These are the questions we deal with routinely, and they are worth walking through in order.
1. The Broad Definition Trap: Why Umbrella CAS Numbers Create Supply Chain Friction
In global raw material trading, quoting CAS 97682‑44‑5 without saying anything about crystal water is an open invitation to friction. The number spans everything from partially dried amorphous phases to whatever hydration state a given lot happens to be in. Two suppliers can quote the identical CAS number and still ship material that differs in physical form, water content, and even how fast it dissolves.
The downstream effect shows up in the lab. An R&D group orders under CAS 97682‑44‑5 expecting a uniform powder, and the lots come in with moisture profiles that wander from shipment to shipment. The assay, calculated on an anhydrous basis, shifts with the water content. Karl Fischer results stop being reproducible. Occasionally an X‑ray powder diffractogram picks up a reflection that was not there in the previous lot, and a DSC scan shows a shoulder that nobody expected. For a team trying to validate a stability‑indicating method or a dissolution test under ICH Q2(R1), that kind of lot‑to‑lot drift makes the whole validation suspect and gets in the way of a clean release.
There is a regulatory angle too, and it is easy to underestimate. In a filing, the specification you declare has to line up with what the material actually is. Cite an umbrella CAS number without pinning down the crystal form, and the reviewer will ask about polymorphs and solvates — fairly, because you have left the question open. A trihydrate specification, by contrast, is a reproducible, well‑characterized physical form that removes most of that ambiguity before it ever reaches the desk of an assessor.
2. The Hygroscopic Caking Challenge: Managing Moisture in Bulk Storage
Anhydrous, or otherwise un‑channeled, salt forms are hygroscopic in a way that surprises people who have only handled the trihydrate. Leave the material exposed to ambient humidity during sampling or secondary packaging and it pulls water straight out of the air. The anhydrous lattice has no coordinated crystal water to hold it together, so water adsorbs onto the particle surfaces and then keeps working its way into the bulk.
The practical consequences are familiar to anyone who runs a filling line. Powder cakes, clumps inside fiber drums, and starts to bridge electrostatically. Caking kills flowability and wrecks the uniformity of downstream blending and filling. Worse, trapped moisture can localize and give the lactone ring of the camptothecin skeleton a chance to hydrolyze. The closed lactone is the pharmacologically active species; once it opens to the carboxylate, the material has quietly lost some of its value. That is a stability problem that has to be managed from the moment of manufacture, through storage, and all the way into the customer's process.
◆ At Shaanxi Sunrise — Controlled Handling Protocol
Our approach at Shaanxi Sunrise is deliberately conservative. We dry under deep vacuum with an inert nitrogen purge, then pack the intermediate in double‑layer antistatic LDPE bags inside sealed aluminum canisters with silica gel. The idea is to keep the water activity low during transport and long‑term storage, so the customer receives material in a defined, reproducible physical state rather than something that has drifted while sitting in a container. In our experience the scheme holds up well enough across most climates, though we still advise keeping the anhydrous intermediate cool and dry once it is on site.
Bridging General Salt Definitions into Commercial Specifications
The gap between a broad registry number and a defensible specification is closed by the certificate of analysis, not by the CAS number. The CoA has to say what the physical form is. For irinotecan hydrochloride we would expect to see at least the following on any serious release document:
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assay, expressed on a clearly defined basis;
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water content by Karl Fischer, with an acceptance range that matches the intended hydrate state;
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identification by HPLC retention time, and — where the form matters — confirmation of crystallinity by X‑ray powder diffraction or DSC;
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related‑substance limits;
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residual solvents screened against ICH Q3C;
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a heavy‑metals or elemental‑impurities check per ICH Q3D.
Once those numbers are on the page, an umbrella CAS number stops being a source of doubt. The ambiguity is replaced by analytical evidence anyone can reproduce.
Technical FAQ: CAS 97682‑44‑5 vs. Trihydrate Sourcing
Should our procurement team use CAS 97682‑44‑5 or CAS 136572‑09‑3 for regulatory filings?
For parenteral work under EP/USP, specify CAS 136572‑09‑3 (trihydrate) and say so explicitly. It locks down the crystal form, which is what a reviewer or an auditor is actually looking for. CAS 97682‑44‑5 is best kept for general salt referencing. Making the trihydrate choice explicit tells the quality system that the crystal form was a deliberate, characterized decision rather than an accident.
References
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National Center for Biotechnology Information. PubChem — Irinotecan Hydrochloride (anhydrous; CAS 97682‑44‑5). https://pubchem.ncbi.nlm.nih.gov/compound/Irinotecan‑Hydrochloride
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NCBI PubChem — Irinotecan Hydrochloride Trihydrate (CAS 136572‑09‑3). https://pubchem.ncbi.nlm.nih.gov/compound/IRINOTECAN‑HCl_trihydrate
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FDA / NIH NCATS GSRS — Irinotecan Hydrochloride, UNII 042LAQ1IIS. https://gsrs.ncats.nih.gov/ginas/app/beta/substances/042LAQ1IIS
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DrugBank Online — Irinotecan hydrochloride hydrate (DBSALT001805). https://go.drugbank.com/salts/DBSALT001805
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NLM DailyMed — Irinotecan Hydrochloride Injection, USP. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=9c6aa884‑750e‑4b11‑9955‑bc7ab6e9c2ad
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European Pharmacopoeia (EDQM) — Irinotecan hydrochloride trihydrate CRS, Y0001832. https://crs.edqm.eu/db/4DCGI/View=Y0001832
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USP 35 — Irinotecan Hydrochloride Monograph. https://www.drugfuture.com/Pharmacopoeia/usp35/PDF/3560‑3563%20Irinotecan%20Hydrochloride.pdf
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KEGG DRUG Database — Irinotecan hydrochloride (D01061). https://www.genome.jp/dbget‑bin/www_bget?D01061
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Venditto VJ & Sim DS. Cancer Therapies Utilizing the Camptothecins: A Review of the in Vivo Literature. Mol Pharm. 2010;7(2):307‑349. https://pmc.ncbi.nlm.nih.gov/articles/PMC3733266/
Product FAQ
Q1. Is irinotecan hydrochloride a natural product or a synthetic API?
Semisynthetic. The starting point is camptothecin, a natural alkaloid from the Chinese happy tree (Camptotheca acuminata). Upstream synthesis takes that lead compound, elaborates it into irinotecan, and converts it to the hydrochloride salt. That is the part of the value chain Shaanxi Sunrise covers — turning a natural lead into a standardized, reproducible intermediate.
Q2. Which crystal form should I specify when ordering bulk material?
For formulation and parenteral (EP/USP) work, order the trihydrate under CAS 136572‑09‑3. The crystal form is stable and well characterized. If you are working with an anhydrous intermediate under CAS 97682‑44‑5, moisture control becomes the whole game, and you should put water content and polymorphic form into the CoA acceptance criteria up front.
Q3. What analytical documentation do you provide with each batch?
Each lot ships with a Certificate of Analysis, a batch and purity profile, residual‑solvent data, moisture content, and an MSDS. We write specifications against the European Pharmacopoeia or USP monograph for irinotecan hydrochloride, and we can share supporting chromatographic and stability data on request.
Q4. How is the hygroscopic anhydrous form packaged to prevent moisture uptake?
Deep vacuum drying under a nitrogen purge, then double‑layer antistatic LDPE bags inside sealed aluminum canisters with silica gel. The goal is to keep humidity, caking, and lactone hydrolysis at bay from the moment of packing through to delivery.
Q5. Do you supply only the hydrochloride salt, or also the camptothecin API?
We support camptothecin and camptothecin‑derivative sourcing across a range of purity and physical‑form options. If you are unsure which CAS number or crystal form fits your oncology pipeline, our technical team can help.
Consult Shaanxi Sunrise on Camptothecin API Sourcing
Need help choosing the right CAS number and crystal form for your oncology pipeline? Get in touch with our technical team. The upstream specialists here can walk you from a broad registry identifier to a specification that will hold up in an audit.
Contact Our Technical Experts