Miami physician-entrepreneur Phillip Frost and his wife Patricia have pledged that they will give more than half their wealth to philanthropy and charitable causes. The news was announced Thursday by Giving Pledge, a program started by last June by Warren Buffett and Bill and Melinda Gates to encourage America's most wealthy to donate. The Frost commitment brings to 69 the pledges the group has received. Phillip Frost is frequently listed as a billionaire on America's most wealthy lists by Forbes and other publications. He developed and sold two major pharmaceutical companies, Key Pharmaceuticals and IVAX. He now heads OPKO Health, another drug company, and is major investor in many other enterprises.