Polyurethanes as Carriers of Antitumorous Drugs

Drug delivery systems on a polyurethane base with various antitumorous drugs, such as cyclophosphane, thiophosphamide and vincristine, have been prepared. An in vitro technique was used to determine the release characteristics of the drugs into model biological media. It was shown the drug release occurs in accordance with first-order kinetics, as well a maximum degree for the drug loading were studied. The thermodynamic parameters of drug release has been determined. It was illustrated that the activation energies were 4.3, 3.9 and 3.2 kcal/mole for cyclophosphane, thiophosphamide and vincristine respectively, corresponding to a diffuse-controlled mechanism of release. © 1998 John Wiley & Sons, Ltd.     

Synthesis and In Vitro Study of Antiviral Activity of Glycyrrhizin Nicotinate Derivatives against HIV-1 Pseudoviruses and SARS-CoV-2 Viruses

When developing drugs against SARS-CoV-2, it is important to consider the characteristics of patients with different co-morbidities. People infected with HIV-1 are a particularly vulnerable group, as they may be at a higher risk than the general population of contracting COVID-19 with clinical complications. For such patients, drugs with a broad spectrum of antiviral activity are of paramount importance. Glycyrrhizinic acid (Glyc) and its derivatives are promising biologically active compounds for the development of such broad-spectrum antiviral agents. In this work, derivatives of Glyc obtained by acylation with nicotinic acid were investigated. The resulting preparation, Glycyvir, is a multi-component mixture containing mainly mono-, di-, tri- and tetranicotinates. The composition of Glycyvir was characterized by HPLC-MS/MS and its toxicity assessed in cell culture. Antiviral activity against three strains of SARS-CoV-2 was tested in vitro on Vero E6 cells by MTT assay. Glycyvir was shown to inhibit SARS-CoV-2 replication in vitro (IC₅₀2–8 μM) with an antiviral activity comparable to the control drug Remdesivir. In addition, Glycyvir exhibited marked inhibitory activity against HIV pseudoviruses of subtypes B, A6 and the recombinant form CRF63_02A (IC₅₀ range 3.9–27.5 µM). The time-dependence of Glycyvir inhibitory activity on HIV pseudovirus infection of TZM-bl cells suggested that the compound interfered with virus entry into the target cell. Glycyvir is a promising candidate as an agent with low toxicity and a broad spectrum of antiviral action.     

A comparative study of the NNπ system: (I). The πd → πd, πd → NN channels

Numerical results are presented for πd → πd, πd NN observables for 290 ? T_π (MeV) ? 50. We discuss sensitivity of predictions for various input elements like the deuteron form factor, the range of the NNπ vertex and the parametrization of the background part of the P₁₁πN scattering matrix and remark on possible parallels for A(π, π) and A(π, 2N) amplitudes. A comparison is made with previously obtained results of similar scope.     

A study of charge symmetry breaking effects in elastic π±d scattering

We computed external and internal Coulomb distortions as well as strong charge symmetry breaking (CSB) effects in π^±d→ π^±d. Available data for T_π = 143 MeV indicate the presence of CSB on the level of observed and deduced parameters for different Δ-isobars and the pn mass difference. Data for $\text{T}{}_{\mathrm{\pi }}\text{1}\text{?}\text{80}\text{MeV}$ are predicted to better suit the extraction of a measure of charge symmetry breaking. This note also contains a critical analysis of a previous study of CSB effects on σ_πd^tot.     

A four-channel unitary model for the description of heavy-ion collisions at relativistic energies

We expand a previously formulated model for nuclear abrasion in ion-ion collisions where now nucleons in both projectile and target can be excited. Describing the state of excitation by an effective channel we rigorously impose unitarity and compare the results with those of a heuristic treatment of unitarity by Hüfner, Schäfer and Schürmann. We find corrections to the latter theory which grow up to a factor of two with the number of abraded nucleons.     

New film composites based on alicyclic polyimide

New film composites based on alicyclic polyimide with polyethylene terephthalate and polycarbonate plasticizers were prepared. The thermodynamic parameters of mixing of film materials were determined by differential scanning calorimetry and thermogravimetry. The structure and composition of the resulting materials were studied by IR spectroscopy and X-ray diffraction analysis.     

The first one-pot synthesis of alkoxycyclopropanes via cyclometalation of styrene with ClnAlEt3−n and RCO2R′ mediated by Cp2ZrCl2

The one-pot cyclopropanation of styrene using Cl_nAlEt_3−n (Et₂AlCl, EtAlCl₂, AlCl₃) and carboxylic esters in the presence of Cp₂ZrCl₂ as catalyst gives rise to alkoxycyclopropanes.