1. Department of Chemistry and Biochemistry, Faculty of Pharmacy, Medical University-Pleven, Pleven, Bulgaria
2. Department of Dermatology, Venerеology and Allergology, Faculty of Medicine, Medical University-Pleven, Pleven, Bulgaria
3. Department of Surgical Nursing, Faculty of Health Care, Medical University-Pleven, Pleven, Bulgaria
4. Department of Pharmacology and Toxicology, Faculty of Pharmacy, Medical University-Pleven, Pleven, Bulgaria