What Buyers Need to Know Before Sourcing Orlistat
Orlistat (CAS 96829-58-2) is a semi-synthetic, fermentation-derived active pharmaceutical ingredient (API) with a demanding quality profile. Buying it well means looking past a single assay figure and understanding the grade, the impurity limits, the chiral quality and the documentation that come with the material. This guide sets out what to check when you source Orlistat, how to read its Certificate of Analysis, and how to choose a reliable supplier.
It complements our technical reference on Orlistat’s properties, specifications and applications and our article on the Orlistat manufacturing route.
Grades: USP, EP and Reference Material
Orlistat is supplied against pharmacopoeial monographs, and the grade you need depends on your application and your market.
| Grade | Best for | What it guarantees |
|---|---|---|
| USP grade | Products and QC work aligned to the United States Pharmacopeia | Conformance to the USP Orlistat monograph, with a full COA |
| EP grade | Products and QC work aligned to the European Pharmacopoeia | Conformance to the EP Orlistat monograph, with a full COA |
| Reference / research grade | Analytical standards, method development and research | Documented identity and purity, with lot-specific data |
In practice, USP and EP grades are the same substance tested against two different monographs, and many suppliers can provide material that meets both. If you are developing for a specific market, state the required monograph up front so that the correct specification, testing and documentation are applied.
Reading the Orlistat COA
The Certificate of Analysis is your primary evidence of quality. A complete Orlistat COA should report the following tests, each compared with its specification.
| Test | Specification | Why it matters |
|---|---|---|
| Appearance | White or quasi-white crystalline powder | Quick check on form and gross quality |
| Optical rotation | -48° to -51° (20°C, 30 mg/mL in dehydrated alcohol) | Confirms correct stereochemistry |
| Assay (anhydrous, solvent-free basis) | 98.0% – 101.5% | Confirms active content on the correct basis |
| Residue on ignition | NMT 0.1% | Confirms low inorganic residue |
| Residual water | NMT 0.2% | Limits beta-lactone ring opening |
| Related substances | Individual and total limits per monograph | Controls process and degradation impurities |
One of the most common sourcing mistakes is comparing assay values without confirming the basis. Orlistat assay is reported on the anhydrous, solvent-free basis, which means water and residual solvents are excluded before the result is compared with the 98.0% to 101.5% window. Always confirm the basis on the COA.
Key Specifications Explained
Assay
An assay of 98.0% to 101.5% on the anhydrous, solvent-free basis confirms a high and tightly controlled active content. Because the range is narrow, it also signals a well-controlled manufacturing and purification process.
Optical rotation
Optical rotation is the simplest indicator of chiral quality. Orlistat’s biological activity depends on the correct configuration at its stereocentres, and a result within -48° to -51° confirms that the material has the expected stereochemistry. A value outside this range should prompt investigation, usually by chiral chromatography.
Residual water
Water is not merely a residual solvent for Orlistat – it is a reactant that can open the beta-lactone ring. The limit of not more than 0.2% protects the material against the formation of open-ring epimer and open-ring amide impurities, and it is closely linked to storage and packaging requirements.
Impurity limits
Beyond the total-impurities limit of not more than 1.0%, the monograph controls several named related substances. The table below lists the named impurities and their limits as they typically appear in an Orlistat specification.
| Impurity | Limit |
|---|---|
| Orlistat Related Compound A | NMT 0.2% |
| Orlistat Related Compound B | NMT 0.05% |
| Orlistat Related Compound C | NMT 0.05% |
| Orlistat Related Compound D | NMT 0.2% |
| N-Formyl-L-leucine | NMT 0.2% |
| Orlistat open ring epimer | NMT 0.2% |
| D-Leucine orlistat | NMT 0.2% |
| Orlistat open ring amide | NMT 0.1% |
| Individual unidentified impurity | NMT 0.1% |
| Total impurities | NMT 1.0% |
Packaging, Storage and Shelf Life
Orlistat is typically supplied in double-lined fiber drums – commonly 1 kg, 5 kg or 25 kg – designed to protect the material from light and moisture. Because the beta-lactone ring is sensitive to hydrolysis, packaging integrity is a real quality parameter rather than a formality.
- Storage: below 25°C in tight, light-resistant containers, protected from moisture.
- Handling: minimise exposure to air and moisture; reseal containers promptly after use.
- Shelf life: the retest period and any specific storage conditions are stated on the COA and should be observed.
Documentation and Regulatory Considerations
For regulated markets, the documentation package is as important as the material itself. When requesting a quotation, clarify at the outset which of the following you need.
- Certificate of Analysis (COA) for the specific lot, covering all release tests.
- Safety Data Sheet (SDS) for hazard, handling, transport and disposal information.
- Additional quality or regulatory documents that may be required during customer qualification, depending on the intended market and use.
Because Orlistat is a fermentation-derived API, the manufacturing history and quality-management system behind the material matter. Buyers working toward regulated markets should raise their documentation and regulatory questions early, so that the supplier can confirm what can be provided and under what conditions.
Supplier Evaluation Checklist
When comparing suppliers, a short checklist helps separate reliable sources from opportunistic ones.
| Check | What good looks like |
|---|---|
| Grade and monograph | USP or EP compliance stated explicitly on the COA |
| Assay basis | Reported on the anhydrous, solvent-free basis |
| Impurity profile | All named related substances reported and within limits |
| Chiral quality | Optical rotation within specification; chiral data available on request |
| Water content | NMT 0.2%, with moisture-protected packaging |
| Batch consistency | Consistent COAs across lots |
| Documentation | Complete COA and SDS, with additional documents on request |
| Supply reliability | Clear lead times and the ability to support repeat orders |
Frequently Asked Questions
What is the difference between USP and EP grade Orlistat?
They are the same substance tested against two different pharmacopoeial monographs. The right choice depends on the market and the monograph your product or method references; material can often be supplied to meet both.
On what basis is Orlistat assay reported?
Orlistat assay is reported on the anhydrous, solvent-free basis, with a specification of 98.0% to 101.5%. Always confirm the basis on the COA before comparing results.
Why is the water limit so tight for Orlistat?
Water can open the strained beta-lactone ring and generate open-ring impurities, so residual water is limited to not more than 0.2% and the material is stored and packaged to exclude moisture.
Can I get Orlistat in small quantities for laboratory use?
Yes. The same USP/EP-quality API is available in gram-scale quantities for reference and research use as well as in commercial-scale drums for formulation customers.
What documents should I request with a quotation?
Request the lot-specific COA, the SDS, and a clear statement of any additional quality or regulatory documents the supplier can provide for your intended market.
PolyBlueChem supplies Orlistat (CAS 96829-58-2) as a USP/EP-grade API with a complete Certificate of Analysis. For specifications, quotation or documentation, contact our team.
This article is provided for technical reference only and does not constitute medical, legal or regulatory advice.