Reading a Framycetin Sulfate Certificate of Analysis: What 759 IU/mg Actually Tells You

Our current commercial batch of Framycetin Sulfate API measured 759 IU/mg against a Ph. Eur. minimum of 630 IU/mg — about 20% headroom — with pH 6.3, specific optical rotation +52.6°, loss on drying 6.5%, neomycin C 0.6%, microbial count below 10 cfu/g, and a particle size distribution of D10 15 µm / D50 62 µm / D90 168 µm. This post explains what each number means for your formulation, and why we publish the least flattering result alongside the best one.

Why is a certificate of analysis worth more than a specification sheet?

A specification sheet tells you the limits; a certificate of analysis tells you where your material actually sits inside those limits. Most API suppliers publish only the former. For a hygroscopic aminoglycoside whose potency drifts downward over time, the distance between the measured value and the limit is the number that determines whether your finished product still passes at the end of its shelf life.

What did this batch measure?

This batch measured 759 IU/mg against a 630 IU/mg limit, pH 6.3 against a 6.0–7.0 range, loss on drying 6.5% against an 8.0% limit, and neomycin C 0.6% against a 3.0% limit. Full comparison:

Why does potency headroom above 630 IU/mg matter?

A potency of 759 IU/mg gives your finished product roughly 20% headroom, which functions as a stability budget across the retest period. Aminoglycoside potency declines slowly over time; your formulation must still meet specification at the end of shelf life, not only on release day. Two practical consequences:

1. Your stability data carry more margin — reducing the risk of an out-of-specification result at month 24 or 36.

2. For potency-critical topical and ophthalmic products, a higher starting potency may allow a lower API charge to reach the same delivered activity.

Why publish a specific rotation of +52.6°?

We publish +52.6° because it sits just inside the lower bound of the +52.5° to +55.5° window, and buyers auditing our dossier will see it regardless. A supplier who publishes only flattering results is telling you something about how it handles deviations.

The material is compliant, the value is within specification, and chiral identity is independently confirmed by HPLC, TLC and IR. You should know where the number sits before ordering, not after.

Why report particle size when the monograph does not require it?

Particle size is reported because ointments, creams and ophthalmic suspensions succeed or fail on physical behaviour — blend uniformity, dissolution rate, content uniformity per dose — rather than on chemistry alone. Ph. Eur. 11 sets no particle size limit for framycetin sulfate; we measure it anyway.

A D50 around 62 µm suits conventional dermal and ointment bases. For ophthalmic suspensions or very fine topical systems, we mill to a customer-specified distribution — a capability most trading companies cannot offer.

Why test bacterial endotoxins if the monograph does not require it?

Bacterial endotoxins are tested because framycetin's principal uses — eye drops, ear drops, wound and burn preparations — involve contact with compromised tissue, and ophthalmic manufacturers need an endotoxin position in their own filing. Having the result on the API certificate of analysis removes a step from your incoming-materials qualification.

Why is microbial count below 10 cfu/g significant?

Below 10 cfu/g is an unusually tight result for a non-sterile API. It lowers the bioburden you carry into your own manufacturing — a meaningful advantage if your product is terminally sterilised or aseptically prepared.

Which applications does this batch profile suit?

What documentation and quantities are available?

Every batch ships with COA, MSDS, TSE/BSE statement and origin documentation, with potency released against the Ph. Eur./BP monograph and identity confirmed by HPLC, TLC and IR. DMF reference support is available. Material is packed in moisture- and light-protected double PE-lined foil bags inside fibre drums, stored at controlled room temperature.

Quantities run from 100 g qualification samples to 1 kg, 5 kg and 25 kg commercial packs, with customer-specified particle size distribution and packaging.

FAQ

1. What potency did this framycetin sulfate batch measure?

759 IU/mg on the dried substance, against a Ph. Eur. minimum of 630 IU/mg — approximately 20% headroom.

2. Why is potency headroom important for a finished formulation?

Aminoglycoside potency declines slowly over time. Starting above the monograph minimum provides a stability budget so the finished product still meets specification at the end of its retest period.

3. Is +52.6° within the Ph. Eur. specification?

Yes. The Ph. Eur. window is +52.5° to +55.5° on the dried substance. The value is within specification, close to the lower bound, and we publish it rather than omitting it.

4. Does Ph. Eur. require particle size testing for framycetin sulfate?

No. We measure it voluntarily because particle size governs blend uniformity and dissolution in semi-solid and suspension formulations, and we mill to customer-specified distributions.

5. Are bacterial endotoxins tested?

Yes, although the monograph does not require it. We test because ophthalmic, aural and wound-care manufacturers need an endotoxin position in their own filings.

6. What is the minimum order quantity?

Qualification samples start at 100 g; commercial packs are 1 kg, 5 kg and 25 kg.