ISO 13779-6:2015

Overview

ISO 13779-6:2015 - Implants for surgery - Hydroxyapatite - Part 6: Powders specifies quality and testing requirements for hydroxyapatite (HA) powders used as raw materials for manufacturing or coating surgical implants. The standard focuses on powder-specific parameters (chemical composition, purity, particle size, morphology and batch documentation) and deliberately excludes hydroxyapatite coatings, sintered HA ceramics, glass ceramics and other calcium phosphates (α/β-TCP, TTCP).

Key topics and technical requirements

• Chemical composition and purity
  • Calcium to phosphorus molar ratio (Ca/P) requirement: 1.66 ≤ Ca/P ≤ 1.71 (analysis per ISO 13779-3).
  • Limits for specific trace elements (mg/kg): As 3, Cd 5, Hg 5, Pb 30, and total heavy metals ≤ 30 mg/kg (European Pharmacopoeia method A or validated ICP/AES, ICP/MS, AAS).
  • Any element (other than Ca, P, H, O) > 500 mg/kg must be identified and listed on the certificate.
• Phase purity and crystallinity
  • Foreign crystalline phases (α-TCP, β-TCP, TTCP, CaO) restricted: individual/combined limits set (e.g., CaO ≤ 1%; sum of listed foreign phases ≤ 5%).
  • Crystallinity index and phase analysis per ISO 13779-3; calcination protocols for accurate detection are specified.
• Powder physical properties
  • Morphology: ground or atomized state must be declared and documented by OM/SEM imaging.
  • Granulometry: report D10, D50, D90 (laser diffraction per ISO 24235 or sieving per ISO 2591-1).
  • Calcination loss: for powders with crystallinity ≤ 95%, determine mass loss after 1 h at 1000 ± 25 °C.
• Manufacturing and quality assurance
  • Batch homogeneity validation and a process risk analysis in accordance with ISO 14971.
  • A certificate of compliance must accompany each batch with measured values, acceptance criteria and measurement uncertainty for crystalline content, Ca/P, trace elements, morphology, granulometry and calcination loss.

Practical applications and users

• Target users: implant manufacturers, biomaterials suppliers, medical device quality managers, materials testing laboratories and regulatory compliance teams.
• Use cases: selecting HA raw powders for implant coatings, bone graft substitutes, or feedstock for sintered HA components where consistent chemical purity, particle size and phase composition are critical to biological performance and coating adhesion.

Related standards

• ISO 13779 series: Part 1 (ceramic HA), Part 2 (HA coatings), Part 3 (chemical analysis/crystallinity), Part 4 (coating adhesion)
• ISO 24235 (laser diffraction particle sizing), ISO 2591-1 (sieving), ISO 14971 (medical device risk management)
• European Pharmacopoeia (methods for heavy metals)

Keywords: ISO 13779-6, hydroxyapatite powders, implants for surgery, powder characterization, Ca/P ratio, trace elements, granulometry, certificate of compliance.