Insulin lowers blood glucose levels. It regulates carbohydrate, protein and fat metabolism by inhibiting hepatic glucose production and lipolysis, and enhancing peripheral glucose disposal. The various insulin formulations are classified according to their durations of action after SC Inj. They are divided into short-, intermediate-, or long-acting insulin. Soluble insulin (also known as 'neutral insulin' or 'regular insulin') is a short-acting preparation. To extend the duration of action of insulin, preparations are formulated as suspensions in 2 methods. The 1st method involves complexing insulin with a protein so that it is slowly released, e.g. protamine zinc insulin (contains an excess...