1. Department of Pharmaceutical EngineeringCollege of Chemistry and Chemical EngineeringCentral South University Changsha Hunan 410083 P. R. China
2. Xiangya School of Pharmaceutical SciencesCentral South University Changsha Hunan 410013 P. R. China
3. Department of Medicinal ChemistrySchool of PharmacyHunan University of Chinese Medicine Changsha Hunan 410013 P. R. China
4. Molecular Imaging Research Center of Central South University Changsha Hunan 410013 P. R. China