Medical University of Sofia, Faculty of Pharmacy, 2 Dunav st., 1000 Sofia and Konstantin Preslavski Shumen University, Faculty of Natural Sciences, 115 Universitetska st., 9712 Shumen, Bulgaria.|Medical University of Sofia, Faculty of Pharmacy, 2 Dunav st., 1000 Sofia and Konstantin Preslavski Shumen University, Faculty of Natural Sciences, 115 Universitetska st., 9712 Shumen, Bulgaria.|Medical University of Sofia, Faculty of Pharmacy, 2 Dunav st., 1000 Sofia and Konstantin Preslavski Shumen University, Faculty of Natural Sciences, 115 Universitetska st., 9712 Shumen, Bulgaria.|Medical University of Sofia, Faculty of Pharmacy, 2 Dunav st., 1000 Sofia and Konstantin Preslavski Shumen University, Faculty of Natural Sciences, 115 Universitetska st., 9712 Shumen, Bulgaria.