Stability of powders, capsules and gummies

What degrades in a bulk powder

A bulk powder fails through moisture, oxidation or physical change. The powder is exposed to the air every time the drum is opened, so the in-use stability is shorter than the sealed shelf life. The COA moisture result and the packaging are the first controls.

• Moisture — hygroscopic powders cake, lump and lose flow. NAD+, spermidine and melatonin are the clear cases in this range.
• Oxidation — botanical extracts and flavonoids change colour and assay. Light and oxygen are the drivers.
• Particle size — milling can expose new surfaces and increase moisture uptake.
• Microbiology — a powder with a high water activity is a better environment for mould.

What degrades in a gummy

A gummy fails through water activity, texture or colour. The active is only one part of the matrix; a gummy that passes the active assay but fails the water activity will stick, sweat or grow mould.

• Water activity — the main control; it moves with the drying step and the storage humidity.
• Texture — pectin and gelatin set differently; a change in pH or sugar ratio changes the firmness.
• Colour — natural colours fade; synthetic colours migrate. A colour range and a retention sample are useful.
• Sticking — surface moisture and the bottle material both matter.

The ICH protocol we run

Stability is run on the commercial pack. The standard protocol follows ICH Q1A: long-term, intermediate and accelerated conditions, with the timepoints below. The exact matrix is agreed with the product and the market.

The tests at each timepoint are the release tests plus appearance: assay, moisture, particle size or texture, water activity for gummies, and microbial limits at the start and the end. A stability report that lists only the assay is not a stability report.

Packaging is part of the data

The same powder can pass 24 months in one pack and fail in another. The stability protocol therefore runs on the commercial pack, not on a generic container.

• Foil bag — 1 kg sample pack; a moisture barrier and a zip seal.
• Fibre drum — 25 kg production pack; a liner and a desiccant for hygroscopic powders.
• HDPE bottle — gummies; an induction seal and a desiccant where needed.
• Blister — a better moisture barrier per dose, but a different tooling set.

Product-specific risks

These are the failure modes we see most often in this range. They are not the only ones; the product specification and the destination market decide the final protocol.

What the shelf-life claim means

A 24-month shelf life is a claim supported by real-time data on the commercial pack. Accelerated data underpins the claim but does not replace the real-time study. If your market requires a shorter or longer claim, the protocol and the packaging are adjusted before the batch, not after.

Product-specific notes

Each row maps one product in this range to the parameter this document controls. The product pages link back to their own row; when you compare two products, compare the method column before the number.