1. Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands
2. Department of Pharmaceutics, University of Minnesota, Minneapolis, Minnesota 55455
3. Department of Physics, National Institute of Technology, Rourkela, Rourkela 769008, Orissa, India
4. Laboratory of Physical Chemistry and Colloid Science, Wageningen University, Dreijenplein 6, 6703 HB Wageningen, The Netherlands
5. Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota 55455