Lactobacillus acidophilus is one of the best-known probiotic bacteria, but putting it into a capsule does not automatically protect it from stomach conditions. Viability depends on the strain, the way the bacteria have been prepared, storage and the delivery system.
This matters if you are buying probiotic powder and filling capsules yourself, or developing a small-batch probiotic product.
What happens to L. acidophilus in the stomach?
Acid exposure can reduce the number of viable probiotic cells. The extent varies, which is why it is misleading to give a single survival percentage for every L. acidophilus product.
Researchers have tested delayed-release approaches specifically with L. acidophilus. A 2023 study, for example, evaluated freeze-dried L. acidophilus powders filled into delayed-release vegetarian capsules and then exposed them to simulated gastric fluid. Other work comparing capsule configurations has also used L. acidophilus survival as a measure of protection during simulated gastrointestinal transit.
What did research on DRcaps® find?
A published capsule-comparison study tested several configurations under simulated gastrointestinal conditions. Combinations using DRcaps® showed slower release and higher L. acidophilus survivability than the immediate-release comparator used in that study.
That is useful formulation evidence, but it should be read accurately: it does not prove that every probiotic placed in a DRcaps® shell will have the same result. Powder composition, strain, moisture, storage and whether the capsule is used singly or in a capsule-in-capsule configuration can all change performance.
When does a delayed-release capsule make sense?
If the aim is to avoid releasing a dry probiotic powder immediately after swallowing, a delayed-release shell is a logical formulation option. DRcaps® use an HPMC shell designed for delayed release; they are different from ordinary HPMC capsules and are not a traditional enteric-coated capsule.
For a straightforward plant-based capsule where delayed release is not required, standard HPMC may be sufficient. See our probiotics and stomach acid guide for the wider comparison.
Choosing a capsule size for L. acidophilus powder
Do not choose the capsule from the probiotic dose in milligrams alone. Two powders of the same weight can occupy very different volumes. Bulk density, excipients and flow properties all affect how much fits.
Our empty capsule size chart compares sizes 000 through 5. For a new powder, a small test quantity is the safest way to confirm fit before buying in bulk.
Where to buy empty delayed-release capsules
We stock empty DRcaps® in a range of sizes for compatible dry powders. Browse DRcaps® delayed-release capsules.
References
Feng X et al. Comparison of protection and release behavior of different capsule polymer combinations based on L. acidophilus survivability and function and caffeine release. 2021. PubMed PMID: 34384885.
Moon C et al. Viability of Lactobacillus acidophilus in Thin-Film Freeze-Dried Powders Filled in Delayed-Release Vegetarian Capsules in a Simulated Gastric Fluid. 2023. PubMed PMID: 37740105.
