[1] Med Univ Sofia, Fac Pharm, Dept Pharmacol Pharmacotherapy & Toxicol, Dunav Str 2, Sofia 1000, Bulgaria
[2] Med Univ Sofia, Fac Pharm, Dept Pharmaceut Technol & Biopharmaceut, Sofia, Bulgaria
[3] Univ Siena, Dept Life Sci, I-53100 Siena, Italy
[4] Bulgarian Acad Sci, Inst Polymers, Lab Amphiphil & Ionogen Polymers, Sofia 1113, Bulgaria