Enterosorption

Enterosorption is one of the so-called non-invasive sorption methods, since it does not involve direct contact of the sorbent with blood. At the same time, the binding of exogenous and endogenous toxicants in the gastrointestinal tract by enterosorbents - medicinal preparations of various structures - occurs through adsorption, absorption, ion exchange and complexation, and the physicochemical properties of sorbents and the mechanisms of their interaction with substances are determined by their structure and surface quality.

Absorption is the process of absorption of the sorbate by the entire volume of the sorbent, which occurs in cases where the sorbent is a liquid, and the process of interaction with the sorbate is, in fact, the dissolution of the substance. The absorption process occurs during gastric or intestinal lavage, as well as when enterosorbents are administered in the liquid phase, where absorption occurs. The clinical effect is achieved if the solvent is not absorbed or after administration the liquid is quickly removed from the gastrointestinal tract.

Ion exchange is the process of replacing ions on the surface of the sorbent with sorbate ions. According to the type of ion exchange, anionites, cationites and polyampholytes are distinguished. Substitution of ions to one degree or another is possible in all enterosorbents, but only those where this type of chemical interaction is the main one (ion exchange resins) are classified as ion exchange materials. In some cases, it is necessary to prevent excessive release into the chyme and absorption of electrolytes that occurs during ion exchange in the enteral environment.

Complex formation occurs during neutralization, transport and removal of target metabolites from the body due to the formation of a stable bond with the ligand of a molecule or ion; the resulting complex can be either soluble or insoluble in liquid. Among enterosorbents, polyvinylpyrrolidone derivatives are considered complexing agents.

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Basic medical requirements for enterosorbents

• non-toxicity Drugs during their passage through the gastrointestinal tract should not be broken down into components that, when absorbed, are capable of exerting a direct or indirect effect on organs and systems,
• non-traumatic for mucous membranes. Mechanical, chemical and other types of adverse interaction with the mucous membrane of the oral cavity, esophagus, stomach and intestines, leading to damage to organs, should be eliminated,
• good evacuation from the intestines and the absence of reverse effects - an increase in processes that cause dyspeptic disorders,
• high sorption capacity in relation to the removed components of the chyme; for non-selective sorbents, the possibility of losing useful components should be minimized,
• absence of desorption of substances during the evacuation process and changes in the pH of the environment that could lead to adverse effects,
• convenient pharmaceutical form of the drug, allowing its use over a long period of time, absence of negative organoleptic properties of the sorbent,
• beneficial effect or lack of effect on the secretion processes and biocenosis of the gastrointestinal microflora,
• being in the intestinal cavity, the sorbent should behave like a relatively inert material, without causing any reactive changes in the intestinal tissue, or these changes should be minimal and comparable to those that are observed when changing the diet.

Enterosorption is most often performed by oral administration of enterosorbents, but if necessary they can be administered through a probe, and for probe administration, preparations in the form of a suspension or colloid are more suitable, since granulated sorbents can obstruct the lumen of the probe. Both of the above methods of enterosorbent administration are necessary for performing the so-called gastrointestinal sorption. Enterosorbents can be administered into the rectum (colon sorption) using enemas, but the efficiency of sorption with this route of sorbent administration is usually inferior to oral.

Non-specific sorbents in each section of the gastrointestinal tract perform sorption of certain components depending on the composition of the enteral environment. Removal of xenobiotics that have entered the body orally occurs in the stomach or in the initial sections of the intestine, where their highest concentration is preserved. In the duodenum, sorption of gallstones, cholesterol, enzymes begins, in the jejunum - hydrolysis products, food allergens, in the colon - microbial cells and other substances. However, with massive bacterial colonization and high concentrations of poisons and metabolites in the body's bioenvironments, the sorption process occurs in all sections of the gastrointestinal tract.

Depending on specific tasks, the optimal form and dosage of sorbents should be selected. Psychologically, it is most difficult for patients to take granulated forms of sorbents, while well-ground sorbents are more readily accepted, for example, in the form of pastes that have no taste or smell and do not injure the mucous membranes. The latter is inherent in carbon fiber materials.

The most common method is to take enterosorbents 3-4 times a day (up to 30-100 g per day, or 0.3-1.5 g/kg of body weight), but depending on the nature of the pathological process (for example, in acute poisoning), the desired effect is easier to achieve with one shock dose of the drug. To avoid sorption of drugs administered orally, the time interval from their administration to the use of the enterosorbent should be at least 30-40 minutes, but it is still preferable to conduct drug therapy parenterally.

Enterosorption is used in medicine to treat a wide range of acute and chronic diseases accompanied by toxicosis, which allows to increase the effectiveness of other types of treatment and reduce their volume, including extracorporeal methods of detoxification. A positive effect is noted in allergic diseases, bronchial asthma, psoriasis, as well as in various manifestations of atherosclerosis, acute and chronic liver diseases. The method allowed to improve the results of treatment of a number of surgical diseases (acute pancreatitis, purulent peritonitis), renal failure, various infectious diseases, enterosorption had a favorable effect on the course of the wound process.

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Enterosorption technique for acute poisoning

Equipment	Probe for gastric lavage, intestinal lavage, enterosorbents
Preliminary preparation
Sorbent preparation	To introduce the sorbent through the intestinal tube channel into the small intestine, granulated activated carbons are pre-crushed to obtain a homogeneous fine powder. Then take part of this carbon and mix it with 2-3 parts of vaseline oil until an emulsion is formed, which is heated to 37 'C.
Recommended methods	Up to 80-100 g of sorbent orally in the form of a liquid suspension in 100-130 ml of water Introduction of 80-100 g of sorbent in a liquid suspension through a tube after completion of gastric lavage When enterosorption is combined with intestinal lavage, intestinal perfusion is interrupted and 100-200 g of sorbent in the form of an emulsion is introduced into the intestine through a tube, then the introduction of saline enteral solution is continued In case of poisoning with toxins prone to enterohepatic circulation - 50-60 g of sorbent for the first administration, then 20 g of sorbent after 6-8 hours
Indications for use	Clinical moderate and severe acute oral poisoning with sorbed poisons Laboratory toxic concentrations of poisons in biological environments (blood, urine, rinsing water from the stomach and intestines)
Contraindications	Not detected
Complications	Not detected