Acarbose is alpha glucosidase inhibitor. It inhibits the breakdown of complex carbohydrates to simple carbohydrates and thus they decrease the absorption. Glipizide is second generation sulphonylurea which helps in secretion of insulin. Metformin is biguanide which decrease the synthesis of glucose. Exenatide is GLP-1 analogue which delay in gastric emptying, decrease appetite and augment glucose secretion.