Why is insulin so expensive and the cost so difficult to cap?

Washington (AP) — Reining in the soaring prices of insulin has thus far been elusive in Congress, although Democrats say they'll try again — as part of their economic package that focuses on health and climate.The price of the 100-year-old drug has more than tripled in the last two decades, forcing the nation's diabetics to pay thousands of dollars a year for the life-saving medication. Democrats are considering capping the cost of that drug for at least some, although it’