Fullerene Derivatives of Nucleoside HIV Reverse Transcriptase Inhibitors-In Silico Activity Prediction.

Here we present new derivatives of nucleoside reverse transcriptase inhibitors with a C fullerene. The computational chemistry methods used in this study evaluate affinity of designed compounds towards the HIV-1 reverse transcriptase (RT) binding site and select the most active ones. The best of the designed compounds have superior or similar affinity to RT active site in comparison to most active test compounds, including drugs used in anti-HIV therapy.

NEW RENIN INHIBITORS - STABILITY AND ACTIVITY DETERMINATION. PART IV.

A series of new seven potential renin inhibitors containing pseudodipeptides were synthesized. Stability for all compounds (1-7) in homogenates of liver, kidney, lung and in serum, gastric, intestinal juice and in the presence of α-chymotrypsin was determined. Compound 1 was unstable in all determined mediums.

Adsorption of Antifungal Drugs Inside Pristine and Functionalized Fullerenes and Nanotubes: DFT Investigation.

Background: Econazole, sulconazole and tioconazole usage as antifungal agents is limited due to poor pharmacokinetic properties. Pristine and hydroxylated structures of the C240 fullerene and single walled carbon nanotube (SWCNT) were proposed as transporters of these imidazoles potentially enhancing their pharmacokinetics.

Methods: To assess possibility of creation of the endohedral complexes of the azoles and carbon nanostructures, their adsorption and interaction energies were calculated with the hybrid exchange-correlation density functional B97-1 and 6-31(d,p) basis set.

IDENTIFICATION AND DETERMINATION OF RUPATADINE AND FEXOFENADINE BY DENSITOMETRIC METHOD.

Simple, precise and accurate densitometric methods were developed for the determination of two antihistamine drugs. rupatadine and fexofenadine. Silica gel 60 F₂₅₄ HPTLC plates were used as stationary phase, while mixtures of acetonitrile - water - 25% ammonia (90 : 10 : 1, v/v/v) and acetonitrile - methanol -acetate buffer at pH 5.

NEW RENIN-INHIBITORS--STABILITY AND ACTIVITY DETERMINATION. PART III.

A series of new four potential renin inhibitors containing pseudodipeptides were synthesized. Stability for all compounds (1-4) in homogenates of liver, kidney, lung and in serum, gastric, intestinal juice and in the presence of α-chymotrypsin was determined. Compound 1 was unstable, compounds 2, 3 were stable, compound 4 was partly unstable, (liver and kidney homogenates, (α-chymotrypsin solution).

Novel renin inhibitors containing derivatives of N-alkylleucyl-β-hydroxy-γ-amino acids.

In search for new drugs lowering arterial blood pressure, which could be applied in anti-hypertensive therapy, research concerning agents blocking of renin-angiotensin-aldosteron system has been conducted. Despite many years of research conducted at many research centers around the world, aliskiren is the only one renin inhibitor, which is used up to now. Four novel potential renin inhibitors, having structure based on the peptide fragment 8-13 of human angiotensinogen, a natural substrate for renin, were designed and synthesized.

IMPACT OF STRESS FACTORS ON OPTICAL ISOMERISM OF BENAZEPRIL HYDROCHLORIDE.

Benazepril hydrochloride contains two stereogenic centers, but is currently available as single enantiomer (S,S configuration) for the treatment of hypertension. Its enantiomer (R,R configuration) and the diastereoisomeric pair (R,S and S,R) can be regarded as impurities. Stereochemical stability of S,S isomer of benazepril hydrochloride and its potential susceptibility to conversion in the.

SYNTHESIS AND STUDY OF HALOGENATED BENZYLAMIDES OF SOME ISOCYCLIC AND HETEROCYCLIC ACIDS AS POTENTIAL ANTICONVULSANTS.

A series of potential anticonvulsants have been synthesized. There are eight fluorobenzylamides and three chlorobenzylamides of isocyclic or heterocyclic acids. Two not halogenated benzylamides were also synthesized to compare the effect of halogenation.

DEVELOPMENT OF CHROMATOGRAPHIC METHOD FOR DETERMINATION OF DRUGS REDUCING CHOLESTEROL LEVEL--STATINS AND EZETIMIBE.

The presented developed HPLC method and GC method may be used to separate and determine all analyzed 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) and ezetimibe using a single columns and a uniform methodology. In order to perform qualitative and quantitative tests of statins and ezetimibe the Symmetry C18 column 250 mm x 4.6 mm, 5 µm, the mobile phase: acetonitrile:water (70:30, v/v), adjusted to pH = 2.

Cytisine basicity, solvation, logP, and logD theoretical determination as tool for bioavailability prediction.

Cytisine, an α4β2 nicotinic receptor partial agonist, is a plant alkaloid widely used as a smoking cessation agent. Despite long history of use, knowledge on pharmacokinetics of cytisine still demands an extension. This work is aimed at theoretical determination of physicochemical parameters that affect the bioavailability of cytisine.

Physicochemical properties of lomefloxacin, levofloxacin, and moxifloxacin relevant to the biopharmaceutics classification system.

The aim of this investigation was to identify the impact of physicochemical properties of three fluoroquinolones (second, third, and fourth generation) on bioavailability in relation to the Biopharmaceutics Classification System (BCS) by in silico and in vitro methods. These properties were estimated by analyzing the electrostatic potential pattern and values of the free energy of solvation as well as the distribution coefficients and true partition coefficients of the studied compounds. This study was based on theoretical quantum-chemical methods and the in vitro shake-flask technique with two immiscible phases (n-octanol and phosphate buffer) as well as the experimental potentiometric method to estimate protonation macro- and micro-constants.

A method for rapid screening of interactions of pharmacologically active compounds with albumin.

We determine the association constants for ligand-protein complex formation using the flow injection method. We carry out the measurements at high flow rates (F=1 mL min(-1)) of a carrier phase. Therefore, determination of the association constant takes only a few minutes.

Novel 4-aryl-pyrido[1,2-c]pyrimidines with dual SSRI and 5-HT1A activity. Part 4.

This project describes the synthesis, pharmacological and pharmacodynamic tests on two series of novel derivatives of 2H-pyrido[1,2-c]pyrimidine with potential binary binding to 5-HT1A receptors and SSRI + serotonin transporters. The influence of piperidinyl-indole (8.1-8.

New renin inhibitors--stability and activity determination. Part II.

A series of new six pseudodipeptic potential renin inhibitors were synthesized. Enzymatic stability for all compounds (1-6) in homogenates (liver, kidney, lung) and body fluids (serum, gastric, intestinal juice) and alpha-chymotrypsin was determined. Compounds 4 was stable, compound 5 was unstable and compounds 1, 2, 3, 6 were partly unstable.

New renin inhibitors--stability and activity determination. Part I.

A series of new six potential renin inhibitors containing pseudodipeptides were synthesized. Stability for all compounds (1-6) in homogenates of liver, kidney, lung and in serum, gastric, intestinal juice and in the presence of alpha-chymotrypsin was determined. Compound 5 was unstable, compound 6 was stable, other compounds were partly unstable, compound 2 was stable except kidney homogenate and compound 4 was stable except liver homogenate.

Stability of new anticonvulsant derivatives of picolinic, nicotinic, cyclocarboxylic acids in body fluids and tissues.

The stability of new compounds with established anticonvulsant activity: picolinic acid 4-pyridyl-methylamide (Pic-4-PMA), cyclopentanecarboxylic acid benzylamide (Cpc-BZA), cycloheptanecarboxylic acid benzylamide (Chc-BZA), picolinic acid 2-fluoro-3-trifluoromethylbenzylamide (Pic-2F-3TFM-BZA), 2-chloronicotinic acid benzylamide (2-Cl-Na-BZA), 6-chloronicotinic acid benzylamide (6-Cl-Na-BZA) and 6-trifluoromethylnicotinic acid benzylamide (6-TFM-Na-BZA) in homogenates of body organs and in body fluids was determined after incubation. It was found that three compounds were stable against enzymes present in body fluids and organs and two were found to decompose in liver and kidney homogenates and two decomposed only in liver homogenate.

New renin inhibitors containing phenylalanylhistidyl-gamma-amino acid derivatives in P3 - P1' position.

Five potential inhibitors of renin have been designed and obtained. In the molecule position P3 - P1', crucial for indicating inhibitory activity, all contain phenylalanylhistidylaminoalcanoyl group, ready for interaction with the hydrophobic pocket S3 - S1 of renin molecule. The aminoalcanoyl fragment consists of pseudo-dipeptidic units derivative of gamma-amino acids: of 4-amino-3-hydroxybutanoic acid (AHBA) [26], 4-amino-5-(4-ethoxyphenyl)-3-hydroxypentanoic acid (AEPHPA) [13], 4-amino-5-cyclohexyl-3-hydroxypentanoic acid (ACHPA) (1) and 4-amino-3-hydroxynonanoic acid (AHNA) [21].

Mass spectrometry and molecular modeling studies on the inclusion complexes between alendronate and β-cyclodextrin.

Complexation of alendronate sodium (AlnNa) with β-cyclodextrin (β-CD) was studied by means of ESI-mass spectrometry. The experimental results show that stable 1:1 inclusion complexes between selected bisphosphonates and β-CD were formed. In addition, complexes with different stoichiometry were observed.

New validated HPLC methodology for the determination of (-)-trans-paroxetine and its enantiomer in pharmaceutical formulations with use of ovomucoid chiral stationary phase.

A new chromatographic method for the enantioseparation and the determination of (-)-trans-paroxetine and (+)-trans-paroxetine has been developed with the aid of amylose ovomucoid-based chiral stationary phase. The method is faster and five times more sensitive than procedures recommended previously: limit of detection and limit of quantification are 5 and 16 ng/mL, respectively [modified (Ferretti et al. in J Chromatogr B 710:157-164, 1998): 20 and 60 ng/mL].

Identification and determination of ketotifen hydrogen fumarate, azelastine hydrochloride, dimetindene maleate and promethazine hydrochloride by densitometric method.

Conditions for determination of: ketotifen hydrogen fumarate, azelastine hydrochloride, dimetindene maleate and promethazine hydrochloride by densitometric method in substances and pharmaceuticals were provided. Maximum wavelenghts were: 228 nm for ketotifen hydrogen fumarate, 295 nm for azelastine hydrochloride, 265 nm for dimetindene maleate and 255 nm for promethazine hydrochloride. The limits of quantification were in the ranges of 0.

Prediction of bioavailability of selected bisphosphonates using in silico methods towards categorization into a biopharmaceutical classification system.

The physicochemical properties relevant to biological activity of selected bisphosphonates such as clodronate disodium salt, etidronate disodium salt, pamidronate disodium salt, alendronate sodium salt, ibandronate sodium salt, risedronate sodium salt and zoledronate disodium salt were determined using in silico methods. The main aim of our research was to investigate and propose molecular determinants thataffect bioavailability of above mentioned compounds. These determinants are: stabilization energy (deltaE), free energy of solvation (deltaG(solv)), electrostatic potential, dipole moment, as well as partition and distribution coefficients estimated by the log P and log D values.

Molecular properties impact on bioavailability of second generation triazoles antifungal agents.

The bioavailability of active compounds depends on their two main features: solubility and permeability. The experimental determination of these factors is rather cumbersome. The free enthalpies of salvation deltaG in water and chloroform, and the electrostatic potential surface around examined molecules were ab initio calculated by HF method for voriconazole, posaconazole and ravuconazole.

Synthesis of imperatorin analogs and their evaluation as acetylcholinesterase and butyrylcholinesterase inhibitors.

In this study, we synthesized several imperatorin analogs using imperatorin and xanthotoxin as substrates. The anti-cholinesterase activities of all compounds were evaluated in in vitro experiments according to the modified Ellman's method. For each synthesized compound, IC50 values for both enzymes were established.