1. Department of Pharmaceutical Technology and Biopharmaceutics, Faculty of Pharmacy, Medical University of Sofia, Sofia, Bulgaria;
2. Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, Sofia, Bulgaria;
3. Institute of Polymers, Bulgarian Academy of Sciences, Sofia, Bulgaria;
4. Institute of Organic Chemistry with Center for Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria