Enteric Coated Capsules Explained: When Your Formula Needs Acid Resistance
Enteric coated capsules are two-piece hard capsules with a coating that resists stomach acid and dissolves in the higher pH of the small intestine. They are used when an active ingredient could be degraded by gastric acid or could irritate the stomach. This guide from Capsules Hub Inc., a US supplier of bulk empty capsules […]
Enteric coated capsules are two-piece hard capsules with a coating that resists stomach acid and dissolves in the higher pH of the small intestine. They are used when an active ingredient could be degraded by gastric acid or could irritate the stomach. This guide from Capsules Hub Inc., a US supplier of bulk empty capsules in Islandia, NY, explains how enteric capsules work, which formulas benefit and how to specify them.
Key takeaways
- Enteric coatings resist the acidic stomach (around pH 1.2–3.5) and dissolve in the small intestine (around pH 5.5–7.0).
- Typical candidates include probiotics, digestive enzymes, some botanical extracts and oils, and acid-labile compounds.
- Pre-made enteric capsules let manufacturers fill and close as normal, without a separate coating step on their line.
- Capsules Hub supplies enteric coated capsules on gelatin or HPMC bases, sizes 00–3, in bulk cartons.
What is an enteric coated capsule?
An enteric coated capsule is a hard capsule whose shell is designed to stay intact in stomach acid and open once it reaches the small intestine. The aim is targeted release, not faster release.
Standard gelatin and HPMC capsules are gastrosoluble: they are designed to open in the stomach. An enteric shell changes where the contents are released, which can protect sensitive actives and reduce gastric discomfort for some users.
How do enteric coated capsules work?
They rely on pH. The coating stays insoluble in the low pH of the stomach and dissolves as pH rises in the small intestine.
| Location | Approximate pH | Enteric capsule behaviour |
|---|---|---|
| Stomach | 1.2–3.5 | Designed to stay intact |
| Small intestine | 5.5–7.0 | Coating dissolves and contents are released |
Actual release depends on the coating specification, the fill and storage conditions, so dissolution testing on your finished product is essential.
Which formulas need acid resistance?
Formulas whose actives are degraded by stomach acid, or that cause gastric discomfort when released in the stomach, are the usual candidates for enteric capsules.
- Probiotics and live cultures that need to pass the stomach.
- Enzyme formulations such as bromelain, papain and systemic enzymes.
- Delicate botanical extracts and essential oils, including ingredients that may cause reflux or aftertaste when released early.
- Acid-labile pharmaceutical compounds.
- Ingredients that irritate the stomach when released there.
If your active is stable in acid and well tolerated, a standard gelatin or HPMC capsule is usually simpler and lower cost.
Gelatin or HPMC base for enteric capsules?
Choose the base the same way you would for a standard capsule: gelatin where an animal-derived shell is acceptable, HPMC for vegan or vegetarian lines and moisture-sensitive fills.
| Factor | Enteric on gelatin base | Enteric on HPMC base |
|---|---|---|
| Source | Bovine gelatin | Plant cellulose |
| Vegan claim | No | Yes |
| Typical shell moisture | Higher (about 13–16% for gelatin) | Lower (typically 3–7% for HPMC) |
| Sizes at Capsules Hub | 00, 0, 1, 2, 3 | 00, 0, 1, 2, 3 |
Many probiotic and enzyme products pair an HPMC base with enteric release, because these fills are often both acid-sensitive and moisture-sensitive. For the wider comparison, see gelatin vs HPMC capsules.
Why use pre-made enteric capsules instead of coating in-house?
Pre-made enteric capsules let you fill and close them on your existing encapsulator, without adding a separate coating step after filling.
That can simplify production for manufacturers without coating equipment and avoids reformulating the active itself. You still need to validate the finished product, but the release function comes built into the shell you buy.
What should I consider when specifying enteric capsules?
Define the size, base material, release target and testing requirements, and control fill moisture and storage. These factors decide whether the capsule performs as intended.
- Size. Enteric capsules from Capsules Hub come in sizes 00 to 3. Use the capsule size chart to match your dose volume.
- Release profile. Intestine-targeted release is standard; colon-targeted options can be discussed for specialised formulations.
- Fill moisture. Moist or hygroscopic fills can affect the shell over time; keep fill moisture under control.
- Testing. Plan dissolution and stability testing for your finished product. Capsules Hub can advise on fill compatibility, coating thickness specifications and dissolution testing requirements.
- Appearance. Enteric capsules can be combined with custom colours and printing.
Frequently asked questions
What pH do enteric coated capsules dissolve at?
Enteric coatings are designed to resist the acidic stomach (around pH 1.2–3.5) and dissolve in the higher pH of the small intestine (around pH 5.5–7.0). The exact release profile depends on the coating specification.
Are enteric coated capsules available in a vegan version?
Yes. Capsules Hub offers enteric coated capsules on an HPMC base for plant-based enteric delivery, as well as on a gelatin base.
What sizes do enteric coated capsules come in?
Capsules Hub enteric coated capsules are available in sizes 00, 0, 1, 2 and 3. Custom sizing can be discussed on request.
Do I still need to test my finished product?
Yes. Dissolution and stability depend on your fill, its moisture content and storage. Confirm performance with your own testing before launch.
How do I request a bulk quote?
Send your capsule type, size, colour, approximate quantity, delivery location, timeline and the documents your QA team needs through the Capsules Hub bulk quote form. Specify enteric coated, the base material (gelatin or HPMC), size and colour, and describe your fill so we can advise on compatibility. See the enteric coated capsules page for full specifications.
Capsules Hub Inc. is a US-based supplier of empty two-piece hard capsules, located at 85 Hoffman Lane, Unit W, Islandia, NY 11749. Call 631-819-0355 or email sales@capsuleshub.us. We supply bulk cartons to manufacturers only; we do not sell retail packs.
Sourcing empty capsules for your next production run? Tell us the type, size and quantity and we will reply with bulk pricing and availability.
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