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◆ Quality Series · Part 2
In short: 4.5–5.5 g/L available iodine is not an arbitrary number — it is the registered band at which a povidone-iodine antiseptic kills reliably without unnecessary irritation. Holding it there is a daily control task.
Why available iodine, not total iodine
In povidone-iodine the iodine is bound to a carrier (PVP) and released slowly as available (free) iodine — that free fraction is what actually disinfects. So the meaningful number is available iodine, controlled to 4.5–5.5 g/L, not the total iodine on paper.
Why a band, not "more is better"
Below the band, kill performance drops. Above it — or at the wrong pH — you gain little antiseptic benefit while raising irritation and stability risk. The registered window pairs available iodine 4.5–5.5 g/L with pH 2.0–4.0; both are held together because pH influences how the iodine is released and how stable it stays.
How we hold it in spec
- The povidone-iodine solution is compounded with purified water to the target available iodine.
- Available iodine and pH are verified on every batch with calibrated instruments, against validated test methods.
- Both are checked in process on every batch and recorded in the batch record.
- A light-proof, leak-free pouch then keeps the iodine from evaporating or degrading, so what you test at release is what the user gets.
For buyers — what to ask for: confirm the active is povidone-iodine at 4.5–5.5 g/L available iodine, and ask for the measured available iodine and pH on the COA, tied to the lot.
