High cholesterol levels (or hypercholesterolemia) are associated with many diseases, particularly with the risk of coronary heart diseases. Probucol is commonly used to reduce cholesterol in blood; however, the effectiveness of this drug is highly dependent on its solubility and it is almost insoluble (solubility is about 5 ng/ml in water). Therefore, it is essential to develop approaches to increase the solubility, and thus the bioavailability, to enhance the effi ciency of this drug. We reviewed new methods for increasing the solubility of probucol in water and to enhance

1Laboratory of Pharmaceutics, School of Pharmacy, Nihon University, 7-7-1 Narashinodai, Funabashi, Chiba 274-8555, Japan. E-mail: fukami.toshiro@nihon-u.ac.jp 2Laboratory of Pharmaceutics, School of Pharmacy, Nihon University. aE-mail: suzuki.toyofumi@nihon-u.ac.jp bE-mail: tomono.kazuo@nihon-u.ac.jp 3Department of Chemistry and Biophysics, University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109-1055, USA. E-mail: ramamoor@umich.edu *Corresponding author List of abbreviations after the text.