Određivanje podeonih koeficijenata i solvatohromnih parametara malih organskih molekula primenom tankoslojne hromatografije i hemometrije

Abstract

Cilj ove disertacije bio je razvoj metoda tankoslojne hromatografije za određivanje podeonih koeficijenata, pre svega oktanol-voda (logKOW), zemljište-voda (logKOC), vazduh-voda (logKAW) i solvatohromnih (A, B i S) parametara malih organskih molekula na osnovu kojih se, primenom pristupa lineranih odnosa energije solvatacije (LSER), mogu dalje proceniti: stepen aporpcije u gastrointestinalnom traktu (% Abs), raspodela u sistemu krv-koža (logPskin), voda-koža (logKP, logKSC) i krvmoždana-barijera (log BBB). Za određivanje datih parametara izvorne metode su vremenski zahtevne, podrazumevaju veliku količinu analita i imaju ograničeni radni opseg. Zbog toga su u velikoj meri zamenjene različitim hromatografskim tehnikama, pre svega visokoefikasnom tečnom hromatografijom (HPLC). Međutim, tankoslojna hromatografija ima niz prednosti nad HPLC metodom. To je jednostavna, brza, jeftina metoda, koja koristi male količine analita i reagenasa. Do sada nije sistematski ispitivana njena primena u određivanju pomenutih parametara. U okviru ove disertacije primenjeni su različiti reverezno-fazni i normalno-fazni hromatografski sistemi na skupu od 70 organskih jedinjenja malih molekulskih masa, u kombinaciji sa različitim kalibracionim tehnikama: univarijantna regresija (OLS), regresija glavnih komponenata (PCR), regresija metodom delimičnih najmanjih kvadrata (PLS). Pri tome je izvršena selekcija hromatografskih sistema i definisanje radnih opsega za svaki od proučavanih pariticionih koeficijenata te, tipova organskih jedinjenja na koja se dati izbor hromatografskih uslova može primeniti. Razvijeni postupci su okarakterisani parametrima preciznosti, tačnosti, prediktivne moći i ostalim parametarima validacije modela

The aim of this thesis was the development of thin-layer chromatographic methods for the determination of partition coefficients, primarily octanol-water (logKow), soil-water (logKOC), air-to-water (logKAW ) and Abraham’s solvatochromic parameters of small organic molecules which can be further used to estimate: the gastrointestinal tract absorption (%Abs), the blood to skin distribution (logPskin), water - skin (logKP, logKsc) and the blood to brain partition (logBBB). Original methods used to determine the aforementioned parameters are time consuming, involve a large amount of the analyte and have limited working range. Therefore, they are, to a large extent, replaced by various chromatographic techniques, especially high-performance liquid chromatography. However, thin-layer chromatography has a number of advantages over HPLC method. It is simple, fast, inexpensive method that uses small amounts of analytes and reagents. So far its application in the determination of the parameters mentioned above has not been systematically studied. In the scope of this dissertation, several reversed-phase and normal-phase chromatographic systems were applied on a set of 70 organic compounds of low molecular weight in order to determine the partitioning as well as solvatochromic parameters, in combination with a variety of calibration methods: univariate regression (OLS), principal component regression (PCR), partial least squares regression (PLS). For each of the studied pratitioning coefficients careful selection and definition of chromatographic systems, operating conditions, working ranges and the types of organic compounds on which the developed method could be applied have been done. The developed methods were fruther characterized by the parameters of precision, accuracy, predictive power, and other parameters of the model validation