erbium (169Er) citrate

Erbium citrate (specifically erbium-169 citrate) is a therapeutic radiopharmaceutical used for radiosynovectomy (radiation synovectomy) of small joints, such as the proximal interphalangeal and metacarpophalangeal joints of the hands. Developed by CIS Bio International, it consists of the radionuclide erbium-169, a pure beta emitter, formulated as a citrate colloid. The drug is administered via intra-articular injection into the inflamed joint, where the beta radiation ablates the hypertrophic synovial membrane. Due to its low mean tissue penetration (approximately 0.3 mm), it is ideally suited for small joints to minimize radiation exposure to surrounding healthy tissues. It is primarily indicated for patients with rheumatoid arthritis or seronegative spondyloarthritis who have persistent synovitis despite systemic therapy.

Other names

erbium-169 citrateerbium169 citrateerbium 169 citrate169Er citrateerbium [169Er] citrateerbium citrate