The dossier is nearly finished. The formulation is locked, the claims are drafted, and the toothpaste is scheduled for three EU markets. Then the regulatory reviewer asks for one document the supplier has never been asked to produce: the particle aspect-ratio distribution, counted, with percentages.<\/p>\n
In March 2023, the EU\u2019s Scientific Committee on Consumer Safety adopted its final opinion on hydroxyapatite (nano) \u2014 SCCS\/1648\/22 \u2014 and the numbers in it are precise. The committee \u201cconsiders hydroxyapatite (nano) safe when used at concentrations up to 10% in toothpaste, and up to 0.465% in mouthwash.\u201d That is the sentence suppliers quote. The sentence that decides whether the opinion applies to your<\/em> drum comes earlier: the material must be \u201ccomposed of rod-shaped particles of which at least 95.8% (in particle number) have an aspect ratio less than 3, and the remaining 4.2% have an aspect ratio not exceeding 4.9.\u201d<\/p>\n Two more exclusions close the perimeter. \u201cThis Opinion is not applicable to hydroxyapatite (nano) composed of needle-shaped particles.\u201d And it is \u201cnot applicable to sprayable products that might lead to exposure of the consumer\u2019s lungs to nanoparticles by inhalation.\u201d Breath sprays are out. Needles are out. Coated or surface-modified grades were never assessed.<\/p>\n Notice what kind of rule this is. It does not grade materials from better to worse; it draws a boundary around one tested particle population and stays silent about everything outside it. Silence is not approval. A grade that is 94% below aspect ratio 3 is not \u201cslightly less compliant\u201d \u2014 it is simply not the material the opinion assessed, and a safety case built on the opinion no longer applies to it. Regulators read specifications the way auditors read contracts: the perimeter is the promise, and the promise is only as good as the measurement behind it.<\/p>\n Read the specification again as a measurement task. It is not a shape adjective; it is a number-weighted distribution with a threshold at an aspect ratio of 3 and a hard ceiling at 4.9, established by counting particles in electron micrographs. A datasheet that says \u201crod-shaped nano-hydroxyapatite\u201d asserts a category. The opinion demands a census.<\/p>\n The history explains the strictness. In its earlier assessments the committee \u201cstressed that the available data\/information was not sufficient to exclude concerns over the genotoxic potential\u201d of the material \u2014 concerns it resolved in the final opinion only for the exact particle population described above. The safety conclusion and the shape distribution are not two paragraphs of the same document. They are one finding.<\/p>\n So the compliance question is not \u201cis your material nano-hydroxyapatite?\u201d It is: what fraction of particles, by number, sits below an aspect ratio of 3 \u2014 and does any particle in the tail exceed 4.9? A supplier who runs that count on every lot can answer with a distribution and a micrograph. A supplier who has never been asked will answer with the datasheet adjective, and the gap between those two answers is the difference between an ingredient you can defend in front of a European reviewer and one you cannot.<\/p>\n Shape, in this market, is not a morphology detail. It is the legal identity of the product \u2014 and like every identity, it has to be verified per lot, not asserted per brochure.<\/p>\nWhy \u201crod-shaped\u201d on a datasheet is not compliance<\/h2>\n
The question to send your supplier<\/h2>\n
Sources<\/h2>\n