IRAPACS (Interleukin-1 Receptor Antagonist Protein) is an anti-inflammatory protein that counteracts the destructive effects of inflammatory proteins such as Interleukin-1 (IL-1) within the inflamed joint.

Levels of ACS and other anti-inflammatory proteins in the blood can be increased and produced for joint injection by incubating a 50ml sample of blood from your horse for 24 hours.  The syringe contains glass beads coated with a substance to enhance production of anti-inflammatory proteins. After 24 hours, the syringe is centrifuged, and the serum collected.  The amount of serum collected from each 50ml syringe of blood is usually between 20-25ml.  This yields 5-6 doses of ACS, but the number of doses available for use from each collection is dependent on the specific joint.

Indications for use of ACS in the joint include horses with a well defined (synovitis/capsulitis, particularly those horses that do not respond well to conventional anti-inflammatory joint medication and horses that have had arthroscopic surgery and have been found to have focal cartilage diseases.