1. Department of Pharmaceutical Technology and Biopharmacy, Faculty of Pharmacy, Medical University of Sofia, Dunav Str. 2, 1000 Sofia, Bulgaria
2. Institute of Polymers, Bulgarian Academy of Sciences, Akad. G. Bonchev Str., Bl. 103-A, 1113 Sofia, Bulgaria
3. Department of Pharmacology, Pharmacotherapy and Toxicology, Faculty of Pharmacy, Medical University of Sofia, 2 Dunav St., 1000 Sofia, Bulgaria