In the development of pharmaceutical dosage forms, formulation of hydrophobic drugs represents a great challenge to formulators. Lipid-based nanosized-formulations are among the most attractive candidates for improving drug solubility; microemulsions (MEs) and self-microemulsifying drug delivery systems (SMEDDS) have received particular attention. However, the stability aspects of drug molecules in these formulations have not been widely reported in investigations. This book presents development and formulation of two hydrophobic drugs (ketoconazole (KTZ) and glibenclamide (GBL)) in lipid-based systems to improve their performance considering stability issues. Topical KTZ MEs exhibited significantly improved antifungal activity as proved by wide inhibition zones. Also, GBL MSEDDS showed enhanced dissolution profiles and the in-vivo study reflected a significant improved hypoglycemic activity. The stability testing of drugs in such lipid-based systems was also included. In this book, you will find rational for excipient screening, formulation suggestions, characterization tests, compatibility study, accelerated and long term stability studies for such formulations.