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Pharma or IP grade castor oil is castor oil that meets an official pharmacopoeial monograph — Indian Pharmacopoeia (IP), British Pharmacopoeia (BP), United States Pharmacopeia (USP-NF) or European Pharmacopoeia (Ph. Eur.). The chemistry is the same as other grades; what changes is the standard it is tested against and the documentation behind it. Beyond the usual acid, iodine and hydroxyl values, it is checked for identity, purity, heavy metals and absence of foreign oils, and is expected to come with full batch traceability. It is used as a pharmaceutical excipient, vehicle and formulation ingredient.
There is no separate castor plant for pharma use. Pharma grade starts from the same Ricinus communis seed as every other grade — see what is castor oil for the basics. What sets it apart is that the finished oil is manufactured, tested and documented so that it complies with a published monograph. A monograph is a legal quality standard: it lists the tests a substance must pass and the limits it must meet before it can be used in a medicinal product. Meeting it is a matter of evidence, not opinion.
In practice, that means quality is built in from the start — clean, well-selected seed, careful pressing and refining to protect colour and purity, controlled handling, and testing at the end against the monograph rather than against a general industrial specification.
| Standard | Full name | Primary market |
|---|---|---|
| IP | Indian Pharmacopoeia | India |
| BP | British Pharmacopoeia | UK & aligned markets |
| USP-NF | United States Pharmacopeia – National Formulary | United States |
| Ph. Eur. | European Pharmacopoeia | European Union |
The monographs are broadly similar but not identical, and they are revised over time. The correct reference is always the current edition of the monograph for your destination market — a supplier's claim of "pharma grade" means little unless it names the standard.
The values below are indicative of what a pharmacopoeial castor oil monograph covers. They are for orientation only — the binding limits are those in the current monograph and on the batch Certificate of Analysis.
| Parameter | Indicative value |
|---|---|
| Description | Clear, pale yellow, viscous liquid |
| Identification | Conforms to monograph tests |
| Acid value | Not more than ~2.0 mg KOH/g |
| Hydroxyl value | ~160–168 mg KOH/g |
| Iodine value | ~82–90 g I₂/100g |
| Saponification value | ~176–187 mg KOH/g |
| Specific gravity @ 25°C | ~0.957–0.961 |
| Refractive index @ 25°C | ~1.473–1.477 |
| Water content | Within monograph limit |
| Heavy metals | Within monograph limit |
| Foreign / alien oils | Absent per monograph test |
The first three or four rows look much like any refined grade — the difference is everything below them. Identity, heavy metals and the foreign-oils test are what a general industrial specification usually leaves out. For how to read the resulting certificate, see understanding a castor oil CoA.
For pharmaceutical use the paperwork carries as much weight as the oil itself. A serious enquiry usually covers:
If your application is industrial rather than medicinal, a pharmacopoeial grade is usually unnecessary cost — how to choose the right castor oil grade maps grades to uses.
Castor oil that meets the Indian Pharmacopoeia monograph — tested for identity, purity and specified quality limits, and documented for pharmaceutical use. Equivalent grades exist under BP, USP-NF and Ph. Eur.
The chemistry is the same. Pharma grade is tested against a published pharmacopoeial monograph — including identity, heavy metals and foreign-oil tests that industrial specifications typically omit — and carries fuller documentation and traceability.
As an excipient and carrier in oral and topical formulations, in softgel capsules, in ophthalmic and topical products, in laxative preparations, and as feedstock for ethoxylated castor oil solubilisers.
Which pharmacopoeia and edition the oil is tested to, a batch Certificate of Analysis referencing that monograph, the safety data sheet, quality-system and GMP status of the manufacturing site, and batch traceability to the seed lot.
