Liposomes modified with tetradecyltriphenylphosphonium bromide with dual loading of α-tocopherol and donepezil hydrochloride were successfully designed for intranasal administration. Physicochemical characteristics of cationic liposomes such as the hydrodynamic diameter, zeta potential, and polydispersity index were within the range from 105 to 115 nm, from +10 to +23 mV, and from 0.1 to 0.2, respectively. In vitro release curves of donepezil hydrochloride were analyzed using the Korsmeyer–Peppas, Higuchi, First-Order, and Zero-Order kinetic models. Nanocontainers modified with cationic surfactant statistically better penetrate into the mitochondria of rat motoneurons. Imaging of rat brain slices revealed the penetration of nanocarriers into the brain. Experiments on transgenic mice with an Alzheimer’s disease model (APP/PS1) demonstrated that the intranasal administration of liposomes within 21 days resulted in enhanced learning abilities and a reduction in the formation rate of Aβ plaques in the entorhinal cortex and hippocampus of the brain.

A synthesis procedure and aggregation properties of a new homologous series of dicationic gemini surfactants with a dodecane spacer and two carbamate fragments (N,N′-dialkyl-N,N′-bis(2-(ethylcarbamoyloxy)ethyl)-N,N′-dimethyldodecan-1,6-diammonium dibromide, n-12-n(Et), where n = 10, 12, 14) were comprehensively described. The critical micelle concentrations of gemini surfactants were obtained using tensiometry, conductometry, spectrophotometry, and fluorimetry. The thermodynamic parameters of adsorption and micellization, i.e., maximum surface excess (Г_max), the surface area per surfactant molecule (A_min), degree of counterion binding (β), and Gibbs free energy of micellization (∆G_mic), were calculated. Functional activity of the surfactants, including the solubilizing capacity toward Orange OT and indomethacin, incorporation into the lipid bilayer, minimum inhibitory concentration, and minimum bactericidal and fungicidal concentrations, was determined. Synthesized gemini surfactants were further used for the modification of liposomes dual-loaded with α-tocopherol and donepezil hydrochloride for intranasal treatment of Alzheimer’s disease. The obtained liposomes have high stability (more than 5 months), a significant positive charge (approximately + 40 mV), and a high degree of encapsulation efficiency toward rhodamine B, α-tocopherol, and donepezil hydrochloride. Korsmeyer-Peppas, Higuchi, and first-order kinetic models were used to process the in vitro release curves of donepezil hydrochloride. Intranasal administration of liposomes loaded with α-tocopherol and donepezil hydrochloride for 21 days prevented memory impairment and decreased the number of Aβ plaques by 37.6%, 40.5%, and 72.6% in the entorhinal cortex, DG, and CA1 areas of the hippocampus of the brain of transgenic mice with Alzheimer’s disease model (APP/PS1) compared with untreated animals.

This article considers the antifibrotic properties of pyrimidine derivatives of the drug Xymedon (compound (I)) and its conjugate with L-ascorbic acid (compound (II)) in an experimental rat model of fibrosis with a preventive administration scheme. Experimental fibrosis was induced in Wistar rats given carbon tetrachloride (5% oil solution, 0.2 mL/kg orally twice a week) in combination with ethanol (5% solution in drinking water, free access) against compounds (I) and (II), both administered preventively. Fibrotic changes in the liver were detected by Van Gieson’s staining. The effects of the studied compounds on the liver and clinical condition of rats were evaluated through serum biochemical parameters. The treatment of rats with compounds (I) and (II) reduced the number of fibrotic areas threefold, ameliorated hepatic steatosis and necrosis as compared to the control group, and improved blood biochemical parameters (ALT, AST, and LDH). Interestingly, compound (II) had a more pronounced effect. Therefore, pyrimidine derivatives of Xymedon and its conjugate with L-ascorbic acid showed an antifibrotic effect in our experimental rat model of fibrosis.

“Double” derivatives of the drug Xymedon (1,2-dihydro-4,6-dimethyl-1-N-(hydroxyethyl)pyrimidone-2), hereafter referred to as pyrimidine (I), in which the pyrimidine (I) molecules are joined by an alkyl(xylylenyl)dionate bridge have been synthesized. Primary data on the hepatoprotective activity of five “double” pyrimidine (I) derivatives with different numbers of methylene groups and a meta-xylylene fragment in the ester bridge have been obtained on normal human hepatocytes of the Chang Liver cell line. The cytotoxicity and the cytoprotective properties of the new compounds against the background of exposure to d-galactosamine at a concentration of 150 mmol/L have been determined, their effect on the cell cycle compared with that of the initial pyrimidine (I) has been studied, and the dependence of the biological properties of the derivatives on their structure has been established.