Lanthanum carbonate octahydrate (4d23) authorised for adult dogs until 10 March 2035: 1500–7500 mg/kg feed to reduce urinary phosphorus excretion; lanthanum determined by ICP-AES, carbonate by the EU method of Regulation (EC) No 152/2009
Commission Implementing Regulation (EU) 2025/313, published on 18 February 2025, authorises lanthanum carbonate octahydrate (holder of authorisation: Porus GmbH) as a zootechnical additive in the group “other zootechnical additives” — reduction of urinary phosphorus excretion — for dogs, adults only. The same additive was already authorised for cats. In its opinion of 13 March 2024 EFSA found it safe for adult dogs up to 7500 mg/kg and efficacious in reducing phosphorus bioavailability from 1500 mg/kg; the reference laboratory considered the earlier assessment of methods for cats still valid.
- Annex: additive 4d23 contains at least 85 % lanthanum carbonate octahydrate La₂(CO₃)₃·8H₂O, CAS 6487-39-4, solid form. Methods: carbonate content in the additive — the EU method of Regulation (EC) No 152/2009; lanthanum in the additive and compound feed — inductively coupled plasma atomic emission spectrometry (ICP-AES). Dogs: minimum 1500, maximum 7500 mg additive/kg complete feed with 12 % moisture.
- Conditions (annex): the directions for use must state storage conditions and stability to heat treatment and the text “For adult dogs. Avoid simultaneous use of feed with a high phosphorus content.”; where procedures are not sufficient, respiratory protective equipment — although EFSA considered inhalation exposure unlikely and the additive not irritant to skin and eyes and not a sensitiser.
- EFSA opinion: the rest of the additive is free water; no data on small particles and nanoparticles were submitted, but EFSA considered further characterisation unnecessary because lanthanum carbonate dissolves in acidic gastric fluid. The applicant recommended 340–2100 mg/kg in moist feed (20–25 % dry matter). In the tolerance study dogs tolerated ten times the maximum dose (75 000 mg/kg) without adverse effects; the additive is not genotoxic.
- Literature search 2011–2023 (PubMed, SEARCH, Google Scholar): 40 articles, 7 selected by the applicant, one relevant (Damment 2011) — in dogs no effects on the cardiovascular and respiratory systems after a single intraduodenal dose of up to 2000 mg/kg bw and on behaviour after 52 weeks of oral dosing up to 2000 mg/kg bw. Efficacy relied on studies assessed by EFSA in 2012: shown in cats and in one dog study with reduced urinary phosphorus excretion. No post-market monitoring requirements.