1. Department of Chemistry, Brandeis University, Waltham, Massachusetts 02453, United States
2. Pharmaceutical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
3. Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
4. Division of Molecular Pharmaceutics and Drug Delivery, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States