|
|
Study of inhibition activity of new antitumor drugs against chosen isoforms of cytochromes P450
Kroulíková, Pavla ; Červený, Lukáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Mgr. Pavla Kroulíková Supervisor: RNDr. Jakub Hofman, Ph.D. Title of Thesis: Study of inhibitory activity of new anticancer drugs toward selected isoforms of cytochromes P450 Cytochromes P450 are important biotransformation enzymes that affect pharmacokinetic behavior of many clinically used drugs and are the cause of many major drug interactions. They may have a role in overcoming multidrug resistance of cancer cells because many cytostatic drugs are deactivated by them. Aim of this thesis was in vitro study of inhibition of selected isoforms (CYP3A4, CYP3A5, CYP1A2, CYP2C8, CYP2D6, CYP2C9, CYP2C19 and CYP2B6) by substances from the group of tyrosine kinase inhibitors - alectinib, brivanib, osimertinib and selumetinib. We used commercially available Vividâ CYP Screening kits for the study. In these kits, human cytochromes P450 are recombinantly inserted into insect microsomes. The advantage of this method is that during the experiment no other reaction catalyzed by a different enzyme occurs simultaneously. The principle of this method is conversion of fluorogenic substrate into fluorescent product by CYP450. We determined the inhibition by measuring fluorescence in the 15th minute from start...
|
|
|
Study of effects of antiretroviral drugs on transmembrane transport of tenofofovir disoproxil fumarate across MDCKII-ABCB1 cell monolayer
Repeľová, Beáta ; Červený, Lukáš (advisor) ; Čečková, Martina (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Beáta Repeľová Supervisor: PharmDr. Lukáš Červený, Ph.D. Title of diploma thesis: Study of effects of antiretroviral drugs on transmembrane transport of tenofovir disoproxil fumarate across MDCKII - ABCB1 cell monolayer Tenofovir disoproxil fumarate (TDF) - ester prodrug of tenofovir is considered as one of the most frequently used component of combination antiretroviral therapy. Several ways of application and good patients' tolerability is typical for this compound. TDF is a substrate of dug transporter such as P-glycoprotein (P-gp) therefore its efflux activity may limit the bioavailability after oral administration and distribution of TDF. As many of antiretroviral drugs are also substrates or inhibitors of P-gp, drug - drug interactions with TDF at the level of transmembrane transport could be expected. The aim of the diploma thesis was to describe effects of co-administered antiretroviral drugs on transfer of TDF across MDCKII cell monolayer by using bidirectional transport and concentration equilibrium setups. The results of experiments confirmed that TDF is a substrate of P-gp. High values of efflux ratio describing transmembrane transport of TDF across parental cells have been observed. This...
|
|
| |
|
|
Prepsration of recombinant cDNA of drug transporters
Svobodová, Iveta ; Štaud, František (advisor) ; Červený, Lukáš (referee)
CDS for ABCC4 and ABCC5 transporters were amplified. For ABCC5 two systems were outlined, however the only first one was used. The optimal annealing temperature was 64 řC; optimal concentration of magnesium was 2mM. TOPO XL have proved best results in our research in between cloning kits we tried. The CDS for ABCC4 and ABCC5 were cloned into the vector. Inserts were rended with the use of restrictive endonucleasis. ABCC4 was gashed by Spe I and Not I and ABCC5 by EcoR I and Hind III. With the same endonucleasis, the process of rending was repeated for pZeoSV2(-). Afterwards, the inserts were cloned into pZeoSV2(-).
|
|
|
Transport nesteroidních antiflogistik přes hematoencefalickou bariéru in vitro
Nováková, Iveta ; Štaud, František (advisor) ; Červený, Lukáš (referee)
The migration of substances between the blood circulation and the central nervous system (CNS) is regulated by the blood-brain barrier (BBB). Small, lipophilic molecules such as carbon dioxide, oxygen or ethanol can pass the BBB by passive, transcellular diffusion, while the paracellular transport of hydrophilic substances is restricted by intercellular tight junctions. Due to accessory transport systems, the BBB is able to regulate specifically the permeation of substances (e.g. nutrients) (Ballabh et al., 2004). Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly used substances world-wide, yet little is known about their ability to cross the BBB. Since NSAIDs may exhibit CNS side effects including dizziness, headaches and drowsiness we sought to study the transport of several NSAIDs (celecoxib, diclofenac, ibuprofen, lornoxicam, meloxicam, piroxicam and tenoxicam). Both single studies and group studies were carried out applying either a single substance or several substances simultaneously across the BBB in vitro model based on the human cell line ECV304. The permeability data were normalized to the internal standards diazepam and carboxyfluorescein to account for cell layer's variabilities. According to our studies, it was confirmed that crossing of ibuprofen and...
|
|
| |
|
|
In vitro and ex vivo study of drug-drug interactions of antivirals on intestinal membrane transporters
Halodová, Veronika ; Červený, Lukáš (advisor) ; Vokřál, Ivan (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Veronika Halodová Supervisor: doc. PharmDr. Lukáš Červený, Ph.D. Title of diploma thesis: In vitro and ex vivo study of drug-drug interactions of antivirals on intestinal membrane transporters Tenofovir (TFV) is the first-line agent in the treatment of hepatitis B virus (HBV) infection for patients aged over 12 years and one of the first-line choices for the combination antiretroviral therapy (cART) of infections caused by human immunodeficiency virus (HIV). Two commercially available prodrugs have been developed for oral administration of TFV, tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide fumarate (TAF). These prodrugs increase TFV membrane permeability and oral bioavailability. One of the factors that can affect the bioavailability of orally administrated drugs is active transport mediated by efflux transporters, mainly by P-glycoprotein (ABCB1, P-gp) and Breast cancer resistance protein (ABCG2, BCRP). It has been already proved that TDF and TAF are substrates of both of these transporters. The goal of this diploma thesis was to use in vitro and ex vivo models of intestinal barrier to assess the impact of the efflux transporters on TDF and TAF transport in the intestine and on their...
|
|
|
Characterization of ligand binding to M1 muscarinic acetylcholine receptor using fluorescence anisotropy method
Danková, Hana ; Vokřál, Ivan (advisor) ; Červený, Lukáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Hana Danková Supervisors: Prof. Ago Rinken, PhD. MSc. Tõnis Laasfeld PharmDr. Ivan Vokřál, PhD. Title of diploma thesis: Characetrization of ligand binding to M1 muscarinic receptor using fluorescence anisotropy method Muscarinic acetylcholine receptors (mAChRs), members of the superfamily of G-protein coupled receptors (GPCRs), regulate vital physiological processes and are important targets in drug research. Five different subtypes (M1 - M5) have been identified. M1 mAChR is mainly distributed in the central nervous system and is linked to pathophysiology of neurodegenerative diseases. In recent years, fluorescent methods have been frequently used in studies of ligand binding to receptors. The fluorescence anisotropy (FA) is a homogenous assay to characterize ligand binding to receptors. In this work, we have evaluated the FA method with fluorescent ligand MK342 binding to M1 mAChRs expressed on budded baculovirus (BBV) particles. The fluorescence ligand was binding with the high affinity (4,4 nM) to M1 receptor in constructed BBV preparation. The apparent binding affinities (pKi) of eleven classical and three bitopic muscarinic ligands were screened and compared to previously published...
|
|
|
Effect of anthelmintics on the transport of drugs in the intestine
Štefanová, Anna ; Vokřál, Ivan (advisor) ; Červený, Lukáš (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Student: Bc. Anna Štefanová Supervisor: PharmDr. Ivan Vokřál, Ph.D. Title of diploma thesis: Effect of anthelmintics on the transport of drugs in the intestine Several classes of drugs are currently available for the treatment of helminthiasis in humans and animals, the so-called anthelmintics. Most of these drugs are administered by the oral route, where absorption into the systemic circulation occurs through the intestinal barrier. However, the course and extent of this absorption may be limited by biotransforming enzymes and transport proteins, in particular the family of so-called ATP-binding cassette transporters. These transporters are capable of returning many xenobiotics, including many drugs, back into the lumen of the gut and are the first line of defence against the entry of these substances into the body. An important representative of this group of transporters is P-glycoprotein, which is known for its broad substrate specificity. On this transporter, drugs can act as substrates but also as inhibitors and/or inducers, which may lead to the risk of drug-drug interactions. There is relatively little information about the effect of anthelmintics on P-glycoprotein inhibition. The most studied...
|
|
|
In vitro and ex vivo study of drug-drug interactions of antivirals on intestinal membrane transporters
Halodová, Veronika ; Červený, Lukáš (advisor) ; Vokřál, Ivan (referee)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Veronika Halodová Supervisor: doc. PharmDr. Lukáš Červený, Ph.D. Title of diploma thesis: In vitro and ex vivo study of drug-drug interactions of antivirals on intestinal membrane transporters Tenofovir (TFV) is the first-line agent in the treatment of hepatitis B virus (HBV) infection for patients aged over 12 years and one of the first-line choices for the combination antiretroviral therapy (cART) of infections caused by human immunodeficiency virus (HIV). Two commercially available prodrugs have been developed for oral administration of TFV, tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide fumarate (TAF). These prodrugs increase TFV membrane permeability and oral bioavailability. One of the factors that can affect the bioavailability of orally administrated drugs is active transport mediated by efflux transporters, mainly by P-glycoprotein (ABCB1, P-gp) and Breast cancer resistance protein (ABCG2, BCRP). It has been already proved that TDF and TAF are substrates of both of these transporters. The goal of this diploma thesis was to use in vitro and ex vivo models of intestinal barrier to assess the impact of the efflux transporters on TDF and TAF transport in the intestine and on their...
|
guest ::
RSS feed.