Abstract
A successful bench sample justifies the next defined trial only when its identity, test conditions and decision criteria are traceable. This proposed workflow helps HA, β-TCP and 45S5 buyers plan a sample evaluation, investigate failures and define evidence for a pilot order. It does not prescribe a universal sample count or qualify a finished device.
1. Agree what the sample must demonstrate
Write the intended process, the required material attributes and the practical endpoint before testing. Examples include redispersibility in a chosen liquid, handling in a defined formulation or phase retention after a defined thermal step. Select endpoints that inform the next purchase decision, rather than collecting tests without a decision attached.
Define acceptance criteria, a comparison material, test conditions and a response to failure. Choose sample quantity and independent lots from the trial needs and risk assessment. Repeated readings of one preparation are not additional production lots. Reserve sufficient material for a justified investigation or repeat.
2. Receive and preserve the evidence
Record grade, form, lot, received mass, packaging condition and document revisions. Photograph any abnormal condition and resolve identity discrepancies before interpreting test data. Store and handle the sample according to the applicable SDS and supplier instructions; log opening and preparation dates.
If particle size or BET area will be compared, retain the method and preparation conditions with the result. ISO 13320 concerns laser-diffraction PSD and ISO 9277 concerns gas-adsorption surface area [1,2]. Neither defines a universal functional acceptance limit for these materials.
3. Trial the material in the intended process
Compare the candidate and reference under the planned conditions. Keep specimen preparation, mixing sequence, conditioning and measurement settings traceable. Record failures and missing data. If a result changes, first check identity, preparation and method comparability before attributing the change to the material.
For HA or β-TCP exposed to heat, decide whether the processed phase composition must be checked. For 45S5 exposed to liquid, record the medium, material dose, time and temperature when interpreting the result. These are trial-design prompts; the actual test plan must fit the application.
4. Define the next decision explicitly
Close the trial as advance, investigate or stop against the agreed criteria. Name the pilot grade, scale, process conditions and remaining questions. Confirm whether the sample and pilot supply share the manufacturing route and specification; document and evaluate relevant differences. Confirm current terms before the pilot order.
Agree how relevant grade, process, site or test-method changes will be communicated before subsequent supply. Where a formal conformity statement is required, agree the decision rule [3]. Keep material screening, pilot feasibility and finished-device qualification as distinct decisions.
Table 1. Evidence to carry from the sample request to the pilot decision.
| Stage | Record to retain | Question that permits progress |
|---|---|---|
| Plan | Endpoint, criteria, comparator and sample plan | Will this trial answer the buying question? |
| Receive | Grade, lot, condition and applicable documents | Is the received material identified? |
| Evaluate | Protocol, raw results, deviations and findings | Were the agreed criteria met? |
| Pilot decision | Disposition, remaining risks and next order scope | What has been justified at the next scale? |
References
[1] ISO. ISO 13320:2020. Particle size analysis — Laser diffraction methods. Geneva: ISO; 2020.
https://www.iso.org/standard/69111.html
[2] ISO. ISO 9277:2022. Determination of the specific surface area of solids by gas adsorption — BET method. Geneva: ISO; 2022.
https://www.iso.org/standard/71014.html
[3] ILAC. ILAC-G8:09/2019. Guidelines on decision rules and statements of conformity. Silverwater: ILAC; 2019.
https://ilac.org/publications-and-resources/ilac-guidance-series/