1Department of Chemistry, Faculty of Pharmacy, Medical University, Dunav St.2, Sofia 1000, Bulgaria. 2Department of Statistics, Dokuz Eylul University, Izmir, Turkey 3Institute of Chemical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl.103, Sofia 1113, Bulgaria 4Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, 87036 Rende, Italy 5Laboratory of Chemometrics and Environmetrics, Faculty of Chemistry and Pharmacy, Sofia University “St. Kliment Ohridski”, J. Bourchier Blvd. 1, Sofia 1164, Bulgaria. 6Chemistry Department, The Hashemite University, P.O. Box 150459, Zarqa 13115, Jordan