Notes: 6α-Methylprednisolone 21-acetate is a synthetic glucocorticoid and an ester form of methylprednisolone (Item No. 15013).{62764} It reduces IL-1β-induced production of prostaglandin E2 (PGE2; Item No. 14010) and increases in matrix metalloproteinase-13 (MMP-13) levels in equine osteochondral and synovial explant cocultures when used at concentrations ranging from 1 to 100 nM. Intramuscular injection of 6α-methylprednisolone 21-acetate (20 mg/kg) induces retinal lipid peroxidation and apoptosis in rabbits.{62765} Formulations containing 6α-methylprednisolone 21-acetate have been used in the treatment of joint pain and swelling associated with arthritis.