SOLUTIONS OF HIGHMOLECULAR COMPOUNDS High molecular weight substances (HMWS) are compounds consisting of large molecules (macromolecules) with a molecular weight from several thousand to a million or more Macromolecules are in the form of long elongated or coiled chains or spherical globules. Currently, more than three thousand names of VMV are used in medicine. HMWS classification By the way to receive Natural Synthetic Protein Carbochain Higher polysaccharides Heterochain Protein Gelatin, gelatose, collagen, etc., including enzymes: pepsin, trypsin, deoxyribonuclease Высшие полисахариды Starch, cellulose and its derivatives, dextrins, pectin substances, mucus, gums Carbochain Polyvinyl alcohol, polystyrene, polyvinylpyrrolidone Heterochain Cellulose derivatives (methylcellulose, carboxymethylcellulose), polyglycols, polyamides HMWS classification On the application Medicinal substances Excipients bases or components of bases for ointments and suppositories, emulsifiers, stabilizers, prolongers Properties of the HMWS ❑ Due to their high molecular weight, high molecular weight substances are non-volatile, ❑ not distilled with water vapor, ❑ do not have a specific temperature melting, ❑ are distinguished by high viscosity, ❑ sensitive to environmental factors. ❑ most HMWS represent are amorphous or solid glassy masses or elastic bodies The features of the technology of HMWS solutions depend on the structure of the molecules. HMWS are divided into two groups according to the shape of the molecules: with a spherical (proteins) and linear (starch, cellulose derivatives, etc.) structure The dissolution of substances with a spherical molecular shape differs little from the dissolution of low molecular weight substances. The dispersion bond between such molecules is small. Molecules are easily hydrated and go into solution. Such HMWS are called infinitely swelling, the swelling stage directly goes into dissolution HMWS with a linear structure of macromolecules consist of a large number of monomers connected in series by chemical bonds. Such molecules are flexible, they can coagulate, forming globules (spirals) or elongated chains (fibrillar bundles). Polar groups have the ability to hydrate, that is, to orient water molecules and hold them During the thermal movement of macromolecules, gaps (gaps) are formed between them, into which water easily penetrates. Water molecules are more mobile, therefore, first diffusion of water molecules into the HMWS occurs. In this case, water molecules are oriented around polar groups, hydrating them and forming a monomolecular layer. HMWS swell, increasing in volume 10-15 times When the bond between the HMWS molecules is weakened, they diffuse into the water, forming a true solution. Swelling does not always end with dissolution. In many cases, after reaching a certain degree of swelling, the process stops, since high molecular weight substances and a solvent (water) are able to mix in a limited way. Production of solutions of infinitely swellable substances Pepsin is a proteolytic enzyme obtained from the mucous membrane of the pig's stomach. Apply 2%, 3% and 4% solutions in combination with hydrochloric acid. The activity of pepsin is manifested at a pH of the solution equal to 1.8-2.0 Rр.: Pepsini 3,0 Sol. Acidi hydrochlorici 2 % 200 ml М.D.S. По 1 столовой ложке 3 раза в день, во время еды Pepsin is easily inactivated in a strongly acidic environment, therefore, an acid solution is first prepared, i.e. 160 ml of purified water and 40 ml of hydrochloric acid concentrate are mixed in a stand 1: 10, then pepsin is dissolved Strain the pepsin solution (if necessary) through a loose cotton swab. Filtration paper is not used, since in an acidic medium the protein (amphoteric compound) acquires a positive charge, and the paper, hydrolyzing, is charged negatively, as a result of which the adsorption of the protein on the paper is possible. Making solutions limited swelling substances Rр.: Sol. Gelatinae 4 % 50 ml D.S. По 2 десертные ложки через 2ч 2.0 g of gelatin is poured with 4-10 times the amount of water and left to swell for 30-40 minutes. Then add the rest of the water and heat in a water bath at a temperature of 60-70 ° C until complete dissolution. The warm solution is filtered through a loose cotton swab or a double layer of gauze For gelatin solutions with a concentration of more than 1.5%, a warning inscription "Before use, warm up to the formation of a solution" is required, the bottle must be immersed in warm water so that the jelly frame collapses and a readily mobile liquid is formed Starch consists of two main fractions (parts): 10-20% water-soluble amylase and 90-80% water-insoluble amylopectin swelling in it. Starch is insoluble in cold water, in hot water its grains swell and form a thick liquid - starch paste For internal use and for enemas, a 2% starch solution is prepared by weight according to the prescription of GF VIII: 1 part starch 4 parts cold purified water 45 parts of hot purified water 45 ml of water is boiled in an evaporating cup and a suspension of 1.0 g of starch in 4 ml of cold water is poured with thorough stirring. If necessary, the mass of the solution is brought to 50.0 g Gum solutions Gum solutions (apricot, gum arabic) are liquid dosage forms that can be combined by the common name of mucus (Mucilagines) A peculiar feature of mucus is the high viscosity characteristic of HMWS solutions and, due to this, high enveloping properties. Covering the mucous membranes, gum solutions cover the absorption of medicinal substances introduced with them, thereby lengthening the effect of the latter. Mucus reduces the local irritant effect of certain medicinal substances (for example, chloral hydrate) Taste sensations (sour, sweet) are reduced if these flavors are introduced into the mucus. Mucus, due to protection from external influences, reduces inflammation of the mucous membranes (pain, painful reflexes, spasms). In general, the macromolecules of gums are not absorbed at all in the gastrointestinal tract or are absorbed very slowly in a dilapidated form. A solution of apricot gum is prepared in a 1: 3 ratio by gradually adding gum powder to a measured amount of hot water or mixing in a mortar with cold water Extract solutions In the composition of thick and dry extracts, there are more or less gums, mucous substances, vegetable proteins, gelatinized starch Rp: Ammonii chloridi 2,0 Extracti Glycyrrhizae 3,0 Aquae purificatae 180 тl M.D.S.: По 1 столовой ложке 3 раза в день The prescribed prescription is a liquid dosage form - an aqueous solution of infinitely swelling HMWS - an extract of thick licorice and ammonium chloride for internal use. Solution volume is 180 ml A half amount of purified water and 10 ml of a concentrated solution of ammonium chloride 20% are placed in a tempering bottle of orange glass. Another part of the water is used to dissolve the thick licorice extract. To do this, the prescribed amount of licorice extract is weighed onto a piece of filter paper and attached to the rounded part of the pestle with the paper facing up. The latter is separated from the extract by wetting it from the outside with purified water or alcohol. After that, the extract is mixed in a mortar, first with a small amount of warm purified water, then gradually new portions of purified water are added until the extract is completely dissolved, rinsing the mortar with residual water, filtered into a bottle for dispensing with a solution of ammonium chloride. Decorate with a label "Internal" with warning inscriptions "Store in a cool, dark place", "Shake before use", "Keep out of the reach of children" The stability of HMWS solutions is influenced by: ❖ the introduction of electrolytes, ❖ the solubility of the HMWS decreases with the addition of ethanol, glycerin ❖ environmental factors When adding electrolyte salts to HMWS solutions, one should remember about compatibility, the phenomenon of falling out, which is explained by a decrease in the solubility of the HMWS. Dumping of HMWS in solutions is also observed at low temperatures. Under the influence of the above factors, coacervation is also observed - the division of the system into two layers. Coacervation differs from dumping in that the substance of the dispersed phase does not separate from the solvent in the form of flakes, does not compact into a precipitate, and the system as a whole stratifies into two layers - a concentrated polymer layer in a solvent and a dilute solution of the same polymer Under the influence of some factors, mainly low temperatures, gelation (gelation) of HMWS solutions is possible. This transition of the solution from a freedispersed state to a cohesive-dispersed (gel) state is accompanied by a complete loss of fluidity. The gelling process can continue in the gel itself, while a kind of separation into two phases - "syneresis" - occurs, as a result of which water is released from the jelly. These phenomena must be taken into account when storing solutions. For example, when heating solutions of HMWS (gelatin), the system can be restored, give it fluidity Thanks!
