In the development of a commercial drug product, the formulator must consider various perspectives. The bioavailability of the active drug substance is often the major hurdle to overcome. In the past it has been common to add viscosity-enhancing agents or mucoadhesive polymers into formulations to improve ocular bioavailability. In addition to these conventional approaches, non-conventional technologies such as nanotechnology, microspheres and prodrugs could be considered to optimize the product. Along with bioavailability, the formulator must also consider the tolerability and stability of the final drug product. Quite often, the final formulation is the ideal compromise between the three. Authorities in different parts of the world have set strict requirements and guidelines for development and approval of drug products. In order to secure an expeditious development process and the shortest possible review and approval time, the formulator should be familiar with the current requirements and regulations.