Vol 53, No 4 (2019)

Conjugates for targeted delivery that are based on low-molecular-mass prostate specific membrane antigen (PSMA) inhibitors are widely used and developed because of the deficiencies of existing methods for treating and diagnosing prostate cancer. The major classes of low-molecular-mass PSMA inhibitors, drug classes, and their mechanisms of action are discussed. Therapeutic conjugates for targeted delivery that are based on them are analyzed. Structural features of the linker that affect the biological activity and selectivity are identified.

Schiff base compounds (((1Z,1^′Z)-(((ethane-1,2-diylbis(sulfanediyl))bis(2,1-phenylene))bis(azanylylidene)) bis(methanylylidene)) bis(4,1-phenylene))diboronic acid (1), 1,1′-((1Z,1′Z)-([1,1′-biphenyl]-4,4′-diylbis( azanylylidene)) bis(methanylylidene)) bis(naphthalen-2-ol) (2), 4,4′-((1Z,1′Z)-([1,1′-biphenyl]-4,4′-diylbis(azanylylidene)) bis(methanylylidene)) bis(2-methoxy phenol) (3), (N₄Z,N₄′Z)-N₄,N₄′-bis(4-(dimethyl amino) benzylidene)-[1,1′-biphenyl]-4,4′-diamine (4), (E)-2-((2-hydroxybenzylidene)amino) terephthalic acid (5), and (E)-2-(((2-hydroxynaphthalen-1-yl)methylene)amino)terephthalic acid (6) have been synthesized. The structural identification was confirmed by spectroscopic techniques. The antiproliferative, antiradical, and enzyme activities were investigated in biological experimen0ts. The obtained results showed that Schiff base compounds 1 – 6 exhibited meaningful features in various biological tests. A comparison of compound 1 (containing boron atom in the structure) to compounds 2 – 6 shows that the inclusion of boron in the Schiff base determines whether this would increase or not the efficiency in biological experiments. Hereby, compound 1 exhibited significantly different results in all applications.

The occurrence of amyloid-β (Aβ) and reduced cholinergic tranmission are two major hallmarks of Alzheimer’s disease (AD). Therefore, a series of new 2-phenylbenzo[d]thiazoles substituted with azole/piperazine moieties were designed, synthesized, and evaluated as potential dual inhibitors of Aβ aggregation and cholinesterase (ChE) activities. In vitro studies showed that compound 2m containing an imidazole ring strongly inhibited Aβ_1–40 (49.2%) and Aβ_1-42 aggregation (60.6%). All derivatives exhibited weak inhibitory activities against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Therefore, compound 2m may represent promising therapeutic option for inhibiting Aβ-mediated pathology in AD.

Strategies for determining particulate matter in therapeutic protein injections, including extrinsic and intrinsic particles, are reviewed. Special attention is devoted to the advantages and limitations of various methods used for these purposes, each of which enables different particle characteristics to be determined. The source of particles (extrinsic, intrinsic, or inherent) can be understood better and particle-size distribution and other characteristics can be studied and used to differentiate them if methods based on different measurement principles are used. Protein aggregates in drugs have broad particle-size distributions, from oligomers to particles reaching hundreds of microns. The particle properties can be used to assess the risk associated with protein aggregates in the drug and to study their possible formation mechanisms. Such information could be useful during drug development and manufacturing to reduce the particulate matter content.

Stability study for dolutegravir bulk drug was performed and the degradation products formed were identified by chromatography (HPLC, LCMS) and spectroscopy (ESI-MS, FTIR, ¹H and ¹³C NMR) techniques. Degradation of the drug in acidic and peroxide environment yielded one common major degradant f ((2,4-difluorophenyl) methanamine) with a mass peak at m/z = 182.44. In addition to this, five more minor degradation products (a, b, c, d and e) were formed. The structure interpretation showed that the drug degraded to its synthetic precursor and no extra structures were formed. Hence, it was suggested that drug dolutegravir should be kept away from acidic and oxygen rich conditions.

Several issues with pharmacokinetic studies of new drugs, in particular, experiment planning, development of study protocols, dose selection, and administration routes, are reviewed. The number of used animals is justified statistically with respect to bioethics. The pharmacokinetic study protocol is discussed in more detail according to domestic regulatory requirements. Modern approaches to combining bioanalytical methods with pharmacokinetic studies are described.

Three water-soluble C₆₀-fullerene derivatives functionalized by anionic adducts of various chemical compositions and structures were prepared in highly specific reactions of chlorofullerene C₆₀Cl₆. Hybrid metal-organic complexes formed and aggregated in several instances in aqueous solution in the presence of stoichiometric (1:1 by moles) amounts of synthesized C₆₀-fullerene derivatives and Hg(II) ions. The bioavailability of Hg(II) ions for Escherichia coli cells was reduced by such a reaction and manifested as decreased toxicity for strain E. coli K12 TG1 pF1 or weakened protective reactions of strain E. coli K12 MG1655 pMerA'::lux. The most pronounced protective effect was recorded for the C₆₀-fullerene derivative functionalized by S-containing adducts of general formula –S(CH₂)₁₀CO₂K with antidote activity comparable with that of the pharmacopoeial preparation Unithiol.

The sorption properties of sunflower husk melanins were studied according to pharmacopoeial monograph GPM.1.2.3.0021.15 using marker compounds methylene blue, methyl orange, gelatin, and iodine. The sorption capacities of the studied samples were found to be 190.9 ± 4.2 mg/g for methylene blue; 302.1 ± 1.8, methyl orange; 114.7 ± 2.8, gelatin; and 38.4 ± 2.4%, I₂ . The sorption capacities of the samples were greater than those of the sorbents Polifepan and Polysorb and comparable with that of activated charcoal for medium-molecular-mass toxicants. The melanins showed high affinity for anionic substances. The protein-binding capacities of the melanins were inferior only to that of Polysorb and significantly greater than those of Polifepan and activated charcoal. The sorption capacity for I₂ matched that of Polifepan and was >1.5 times less than that of activated charcoal. The results showed that enterosorbents based on melanins could be developed.

Novel pyrrolo[1,2-a]pyrazine ligands of 18-kDa translocator protein (TSPO) were synthesized at Zakusov Research Institute of Pharmacology. Pharmacological studies of drug substance N-benzyl-N-methyl-1-phenylpyrrolo[1,2-a]pyrazine-3-carboxamide (GML-1) were consistent with high affinity for TSPO and significant anxiolytic activity. A finished dosage form of GML-1 drug substance was developed and exhibited pronounced anxiolytic activity after intragastric administration over a wide dose range.

A method for multiplex digital colorimetric qualitative analysis of nonsteroidal anti-inflammatory drugs (meloxicam, acetylsalicylic acid and its metabolites, paracetamol), β-adrenoblockers (carvedilol), secretolytics (bromhexine), fluoroquinolones (ofloxacin), metabolic stimulants (meldonium dihydrate), etc., was developed. The molecular chip operating efficiency was confirmed by verifying the authenticity of >40 medicinal substances. The proposed universal approach was new in principle and could be used for pharmaceutical quality control.