Biomimetikus katalizátorok fejlesztése mikrofluidikai reaktorokhoz: Development of Biomimetic catalysts for microfluidic reactors

During discovery of drug molecules, metabolism studies are important topic, which are usually carried out in vivo or in vitro using cell based systems. Instead of using living organism-based methods biomimetic systems can offer a promising alternative. Synthetic metalloporphyrins as biomimetic catalysts have strong structural similarity to the active site of the CYP enzymes responsible for the oxidative metabolism of drugs. The applicability and robustness of the porphyrin catalysts can be improved by immobilization techniques involving rationally functionalized solid carriers. The use of magnetic nanoparticles (MNPs) as catalyst carrier provides unique benefits, while the trapping, isolation or separation of the particles from the reaction mixture can be achieved with magnetic field. During my research, MNPs were prepared, modified with reactive function groups for immobilization of porphyrin catalyst, and inert groups which can influence the function group density. The fine-tuned immobilized catalyst was chosen and applied for continuous-flow microfluidical experiment. By the application of the developed biomimetic catalyst and reactor system, drug metabolites can be produced in very rapid way for further stages of drug discovery.   Kivonat A gyógyszervegyületek kifejlesztése során az egyik kritikus fontosságú terület a metabolizmus kutatás, mely során jellemzően in vivo és in vitro májsejt alapú rendszereket használnak, melyek számos hátránnyal rendelkeznek. Az ún. biomimetikus eljárások ígéretes alternatívát jelenthetnek, melyek a kiemelkedő katalitikus hatással bíró szintetikus metalloporfirinekkel megvalósíthatók. A porfirinek alkalmazása a szerkezeti hasonlóságukon alapszik a metabolizmusban részvevő CYP enzimek aktív helyén található hem csoporttal. Az érzékeny porfirin katalizátor alkalmazhatóságát, stabilitását nagyban javíthatjuk, ha valamilyen szilárd hordozó felületére rögzítjük. Mágneses nanorészecskék alkalmazása előnyös katalizátor hordozóként, mivel helyhez rögzítésük vagy elválasztásuk a reakcióelegytől mágneses erőtérrel megvalósítható. Munkám során mágneses nanorészecskék szintézisét és felületmódosítását valósítottam meg. A részecskék felületén a porfirin rögzítésére szolgáló reaktív funkcióscsoportokat, valamint a funkcióscsoport sűrűségét befolyásoló inert csoportokat alakítottam ki. Az ily módon finomhangolt katalizátort sikeresen alkalmaztam folyamatos áramú mikrofluidikai reaktorokban gyógyszermetabolitok szintézisére

Lipid-Based Nanocarriers for Delivery of Neuroprotective Kynurenic Acid: Preparation, Characterization, and BBB Transport

Encapsulation possibilities of an extensively investigated neuroprotective drug (kynurenic acid, KYNA) are studied via lipid-based nanocarriers to increase the blood–brain barrier (BBB) specific permeability. The outcomes of various preparation conditions such as stirring and sonication time, concentration of the lipid carriers and the drug, and the drug-to-lipid ratio are examined. Considering the experimentally determined encapsulation efficiency, hydrodynamic diameter, and ζ-potential values, the initial lipid and drug concentration as well as the stirring and sonication time of the preparation were optimized. The average hydrodynamic diameter of the prepared asolectin-(LIP) and water-soluble lipopolymer (WSLP)-based liposomes was found to be ca. 25 and 60 nm under physiological conditions. The physicochemical characterization of the colloidal carriers proves that the preparation of the drug-loaded liposomes was a successful process, and secondary interactions were indicated between the drug molecule and the polymer residues around the WSLP membrane. Dissolution profiles of the active molecule under physiological conditions were registered, and the release of the unformulated and encapsulated drug is very similar. In addition to this outcome, the in vitro polar brain lipid extract (porcine)-based permeability test proved the achievement of two- or fourfold higher BBB specific penetration and lipid membrane retention for KYNA in the liposomal carriers relative to the unformatted drug

Novel biomimetic nanocomposite for investigation of drug metabolism

In vitro mimicking of hepatic drug metabolism is a key issue in early-stage drug discovery. Synthetic metalloporphyrins show structural similarity with the heme type prosthetic group of cytochrome P450 as primary hepatic enzyme in oxidative drug biotransformation. Therefore, they can catalyze these oxidations. Concerning economical aspects and the poor stability of metalloporphyrin, their immobilization onto or into solid carriers can be promising solution. This study presents a novel immobilized metalloporphyrin nanocomposite system and its potential use as biomimetic catalysts. The developed two-step immobilization procedure consists of two main steps. First, the ionic binding of meso-tetra (parasulphonatophenyl) iron porphyrin onto functionalized magnetic nanoparticles is established, followed by embedding the nanoparticles into polylactic acid nanofibers by electrospinning technique. Due to the synergistic morphological and chemo-structural advantages of binding onto nanoparticles and embedding in polymeric matrices the biomimetic efficiency of metalloporphyrin can be remarkably enhanced, while substrate conversion value was tenfold larger than which could be achieved with classic human liver microsomal system