Dependence of anticonvulsant activity of 1-aryl-1, 5-dihydro-4H-pyrazole (3,4-d) pyrimidine-4-one derivatives on biopharmaceutical factors

Background: We have synthesized three 5-R-1-aryl-1,5-dihydro-4Н-pyrazole(3,4-d)pyrimidine-4-one derivatives that previously have demonstrated powerful anticonvulsant activity. A great number of physicochemical factors are known to influence on bioavailability and stability of active pharmaceutical ingredients. Therefore the purpose of research was to determine the effect of purification technology and dispersibility of 5-R-1-aryl-1, 5-dihydro-4Н-pyrazole (3,4-d) pyrimidine-4-one derivatives on their anticonvulsant activity.Methods: The anticonvulsant effect of this compounds was studied in a model of pentylenetetrazole-induced seizure in mice.Results: The results obtained revealed the optimal solvent for recrystallization of compounds to be isopropanol: compounds, purified by recrystallization from isopropanol, had higher solubility in water and tween; also, they had a tendency to increase anticonvulsant activity. It was found that there is a significant dependence of the latter on compound’s dispersion - the smaller the size of crystals the higher anticonvulsant activity.Conclusions: The dependence of anticonvulsant activity of compounds on the degree of dispersion was proved: the smaller particle size the higher anticonvulsant activity. This can be explained by fast dissolution of fine-dispersed substances, thus increasing the bioavailability if the compounds studied

Diabetes mellitus type 2 in adults

Public organization “Russian Association of Endocrinologists”. Clinical guidelines.&nbsp

Diabetes mellitus type 1 in adults

Public organization “Russian Association of Endocrinologists”. Clinical guidlines

CCCP increases the SkQ-induced efflux of carboxyfluorescein from liposomes.

<p>Carboxyfluorescein (CF) efflux from DPhPC (diphytanoylphosphatidylcholine) liposomes (50 µg/ml), induced by 2.5 µM SkQ1 (panel A) or by 0.5 µM SkQR1 (panel B) was measured with or without CCCP. The efflux was accompanied by an increase in CF fluorescence due to dilution and a relief of CF self-quenching. In panel B, the CF efflux was measured 400 s after the addition of SkQR1. Incubation mixture, 10 mM Tris, 10 mM MES, 100 mM KCl, pH 7.</p

SkQ1 (10-(6-plastoquinonyl)decyl triphenylphosphonium) affects absorption spectra of CCCP in the presence of liposomes.

<p>Incubation mixture: 4 µM CCCP, 1 mM Tris, 1 mM MES, pH = 7.4, containing DPhPC (diphytanoylphosphatidylcholine) liposomes (20 µg/ml) in the absence (curve 1) and in the presence of 1 µM, 2 µM, 4 µM and 9 µM SkQ1 (panel A, curves 2–5, respectively) or in the presence of 1 µM, 2 µM, 4 µM and 9 µM SkQR4 (panel B, curves 2–5, respectively). Insert to panel B shows the dependence of λ_max on the concentration of the SkQ derivatives.</p

Accumulation of lipophilic dications by mitochondria and cells

Lipophilic monocations can pass through phospholipid bilayers and accumulate in negatively-charged compartments such as the mitochondrial matrix, driven by the membrane potential. This property is used to visualize mitochondria, to deliver therapeutic molecules to mitochondria and to measure the membrane potential. In theory, lipophilic dications have a number of advantages over monocations for these tasks, as the double charge should lead to a far greater and more selective uptake by mitochondria, increasing their therapeutic potential. However, the double charge might also limit the movement of lipophilic dications through phospholipid bilayers and little is known about their interaction with mitochondria. To see whether lipophilic dications could be taken up by mitochondria and cells, we made a series of bistriphenylphosphonium cations comprising two triphenylphosphonium moieties linked by a 2-, 4-, 5-, 6- or 10-carbon methylene bridge. The 5-, 6- and 10-carbon dications were taken up by energized mitochondria, whereas the 2- and 4-carbon dications were not. The accumulation of the dication was greater than that of the monocation methyltriphenylphosphonium. However, the uptake of dications was only described by the Nernst equation at low levels of accumulation, and beyond a threshold membrane potential of 90–100 mV there was negligible increase in dication uptake. Interestingly, the 5- and 6-carbon dications were not accumulated by cells, due to lack of permeation through the plasma membrane. These findings indicate that conjugating compounds to dications offers only a minor increase over monocations in delivery to mitochondria. Instead, this suggests that it may be possible to form dications within mitochondria that then remain within the cell

Comparison of SkQ1 and C₁₂TPP effects on the uncoupling activity of DNP and FCCP.

<p>Effects of 2 µM SkQ1, 2 µM C₁₂TPP or 200 µM TPP on the dependence of mitochondrial membrane potential on the concentration of DNP (panel A) or FCCP (panel B). The experiments were conducted in a way shown in Fig. 6. Shown are Mean±S.E. of 4–6 experiments.</p

C₁₂TPP enhances protonophorous effect of 2 nM FCCP (panel A) and 10 µM DNP (panel B) in bilayer lipid membrane (BLM).

<p>Diffusion potential was recorded upon the addition of KOH in one compartment to create ΔpH = 1. Incubation mixture, 10 mM Tris, 10 mM MES, 10 mM KCl, pH 7; C₁₂TPP, 0.1 µM. Control, a record without C₁₂TPP and uncouplers. Plus sign of the potential in the compartment of high pH.</p