Silver containing sorbents: Physicochemical and biological properties

New silver containing sorbents, based on mineral carriers, such as alumina and silica systems with a meso- and macro- porous structure, have a higher mechanical resistance and, hydrophilic and hydrophobic chemical composition of the surface. These sorbents are easy to find and relatively inexpensive, compared to their known equivalents. They are furthermore characterised by high specific surface and simple preparation, whilst the addition of silver considerably increases their antiseptic activity. The results of research of the physical, chemical and biological properties of the developed substances, as well as bio-comparability of sorbents with biological tissues, are presented in this paper. The modified material acts simultaneously as the carrier for active substances to the area of therapeutic application and as a sorbent used to remove toxic agents from such areas. This approach led us to modify the sorbent, and prolong the delivery of substances such as silver, as an effective antibacterial and antimycotic agent

Composition based on aluminum oxide and polydimethylsiloxane matrix for enhancing drug targeting

Methodological approaches developed at Research Institute of Clinical and Experimental Lymphology for a number of years allow formulating the importance of embedding active pharmaceutical ingredients (API) in the structure of porous carriers (sorbents). The composition of the carrier and API is an enteral system for prolonged dosing of pharmacological agents, which allows providing a specific pharmacological effect and safety of use. The pores of the media (sorbents) act as containers for API. This is especially important for rapidly absorbed drugs, which include, for example, lithium preparations that are used in narrow concentration limits due to their side effects. At the moment, an innovative technology for creating new medicines with an improved combination of efficiency and safety (pharmacological upgrade) has been developed and implemented. The essence of the technology is to create a composition of aluminum oxide and polydimethylsiloxane (matrix) and an active pharmacological ingredient (API). A study of two drugs based on matrix / lithium citrate and matrix / melatonin showed continued specific pharmacological activity of API, better pharmacokinetics, and better safety parameters. The matrix of aluminum oxide and polydimethylsiloxane provides an upgrade of the pharmacological properties of drugs for the dosed and safe delivery of API to the zone of their therapeutic effect

MECHANISMS OF ACTION OF LITHIUM COMPOUNDS

This review summarizes the literature data on the role of lithium compounds in modern pharmacotherapy of various diseases of the central nervous system. Attention is also paid to other therapeutic properties of lithium in atherosclerosis, cardiovascular diseases, diabetes, hematopoietic disorders, inflammation, and diseases of the urinary system. Possible ways of delivering lithium into the body have been charted, in particular, when lithium salt is combined with a sorbent (solid porous carrier). Such compounds have additional therapeutic properties. Data on the significance of lithium compounds in studies on models of diseases of the nervous system in animals are analyzed. Among these models, models of neonatal ischemia/hypoxia of the brain in vivo, neurodegenerative diseases, psychopathological states (aggressiveness, depression) and craniocerebral injury are discussed. There are researches in which the results of the lithium preparations use in clinical practice are investigated. It emphasizes the influence of genetic factors on the lithium effects. Particular attention is paid to the possibility of preventing the toxicity of lithium compounds for the body. The currently known molecular mechanisms of lithium action are discussed: inhibition of glycogen synthase kinase 3β (GSK-3β) and inositol monophosphatase 1 (IMPA1), which have key value for autophagy, oxidative stress, inflammation, mitochondrial function, induction of neurotrophic factors, apoptosis. It was concluded that the study of the molecular pathways of the functioning of lithium compounds empowers understanding both the reasons for its effectiveness in the nervous system diseases and the mechanisms of action on other body systems

Studying the pharmacokinetic parameters of new normothymic drug based on the complex of lithium citrate, aluminum oxide and polymethylsiloxane

For the treatment of bipolar affective disorders, lithium preparations are the most famous and effective. But the main problem with the use of lithium preparations is the narrow «therapeutic corridor». An urgent task is the creation of dosage forms of lithium with a slow release and a wide therapeutic range. The study object was a new normotymic drug based on lithium, aluminum oxide and polymethylsiloxane. Due to the new carrier matrix lithium is released from its porous structure gradually providing a prolonged effect and maintaining an optimal concentration in the blood which also helps to minimize side effects. The purpose of the study was to explore the pharmacokinetic parameters of a normotymic drug based on a complex lithium citrate, aluminum oxide and polymethylsiloxane (LOAP).Material and methods: for the assessment of pharmacokinetic parameters the method of atomic emission spectrometry with inductively coupled plasma and two-chamber modeling were used.Results and discussion. The pharmacokinetic data showed a linear nature of pharmacokinetics of the drug based on LOAP as the foundation of data of the lithium’s amount in the blood plasma of rabbits after intragastric administration at doses of 200, 400 and 800 mg/kg. The drug with intragastric administration at a dose of 800 mg/kg is well absorbed from the gastrointestinal tract, with bioavailability (F) 74 %. This dose shows the maximum increase of the area under the pharmacokinetic curve (AUC - 32787.1 (ng x h)/ ml), and indicators of elimination constant (Kel - 0.062 h-1), clearance (Cl - 0.09 l/(kg x h)), elimination half-life (T1/2p - 11.436 h) in comparison with other doses remain unchanged

The effect of silver-containing sorbent on red blood cells during hemosorption: an <i>in vitro</i> study

The aim of the study was to investigate the influence of the original porous silver–containing sorbent on the morphofunctional parameters of red blood cells during in vitro hemoperfusion. Material and methods. Donor blood was perfused through glass columns filled with a sorbent based on porous aluminum oxide, polydimethylsiloxane and silver nanoclusters and a sorbent without silver. The effect of a silver-containing sorbent on the change in morphofunctional parameters of red blood cells after perfusion through sorbents was determined by scanning flow cytometry. Results and their discussion. Due to the uniformity of the distribution of silver (0.1 %) over the sorbent granules, the parameters of the porous structure – the specific surface area and pore volume – practically do not change compared to the sorbent without silver. Morphological parameters of original donor blood and after hemoperfusion are within the norm. The functional parameters are also normal, although the introduction of silver in to the sorbent slightly increases the number of active band 3 (B3) proteins on erythrocyte membranes, both in comparison with the donor red cell mass as a control and in comparison with the sorbent without silver. There is also an increase in the ultimate extensibility of the erythrocyte membrane compared to the original blood (2.2 times) and the sorbent without silver (1.4 times). Conclusions. A sorbent modified with silver and a sorbent without silver does not have a damaging toxic effect on the morphofunctional parameters of blood under perfusion conditions. The mechanisms affecting the indicators of the ultimate extensibility of the erythrocyte membrane after blood perfusion through a silver-containing sorbent require further research

STUDYING THE POSSIBLE MUTAGENIC PROPERTIES OF NEW MEDICINE ON THE BASIS OF COMPLEX LITHIUM CITRATE, ALUMINUM OXIDE AND POLYMETHILSILOXANE

Aim of the study was to investigate the possible mutagenic properties of a new drug based on a lithium-containing substance – a complex of lithium citrate, polymethylsiloxane and aluminum oxide. Material and methods. Methods for testing mutagenicity using chromosomal aberrations in the bone marrow cells of CBA mice and somatic recombination in Drosophila melanogaster were used. Results. It was shown that a single intragastric administration of drug at a dose of 5000 mg/kg and a fivefold course of administration at a dose of 400 mg/kg to CBA mice did not increase the level of cytogenetic disorders in bone marrow cells. The study of the lithium complex drug in a somatic mosaicism test revealed that the preparation at a dose of 2000 mg/kg does not increase the frequency of mutations in Drosophila melanogaster. Conclusion. A single intragastric administration of the studied drug at a dose of 5000 mg/kg and its course administration (400 mg/kg × 5) do not increase the level of cytogenetic disorders in the bone marrow cells of CBA mice. In the somatic recombination (mosaicism) test system on D. melanogaster, no increase in the appearance of mutant setae and spots on the body and head was observed when using yellow and singed markers. The results of the study indicate that the studied drug does not have mutagenic properties

Estimation of acute toxicity of a drug based on the complex of lithium citrate, polymethylsiloxane, aluminum oxide

Research Institute of Clinical and Experimental Lymphology has developed an innovative drug based on a complex of lithium citrate, polymethylsiloxane and aluminum oxide (LOAP). Lithium-based drugs are effective in treating bipolar disorders. However, the toxic effects of lithium cause a “narrow therapeutic window”, which limits its clinical use. The creation of the drug LOAP was aimed at creating a prolonged form with a slow release of lithium to reduce toxic properties and use lithium citrate as an active pharmacological agent. At the moment, the lithium complex has no analogues. The purpose of the study was to study the parameters of acute toxicity of the LOAP. Material and methods. When studying acute toxicity, drugs were administered once intragastrically to mice and rats at doses of 12000, 10000, and 5000 mg/kg. Results. A single administration of drugs intragastrically through a probe in the maximum possible doses to mice and rats did not cause the death of animals and did not cause a locally irritating effect on the gastric mucosa. LOAP can be assigned to hazard class 4 (GOST 12.1.007-76)