Liquid dosage forms: characteristics, classification, manufacturing technology

In pharmacies, we see thousands of different drugs every day. Tablets, sprays, syrups, suspensions ... From this variety, just the head goes around. Which is better: solid or liquid dosage forms? What is the peculiarity of the medicines in the vesicles? Let us examine in detail what is hidden in these mysterious liquids.

What are these drugs for?

Liquid dosage forms have a wide range of applications. Often they are used as an internal remedy, less often as an external one. These drugs are available in a special glass container. They treat colds and eye diseases, cough and ailments of the gastrointestinal tract, and some medicinal liquids are used in the process of complex surgical interventions.

What are they like?

In order for a user to clearly distinguish one kind of medicament in a bubble from another, there is a classification of liquid dosage forms. According to her, all such means can be divided into the following groups:

• Medicines;
• Extracts;
• Syrups;
• Solutions;
• Decoctions and infusions;
• drops;
• Emulsions;
• Baths;
• Tinctures;
• Suspension.

Each of the types has application features. Let's look at these liquid dosage forms in more detail.

Potions

This form of the drug is a powder or liquid. They are usually dissolved in water. Liquid medicine includes in its composition solutions of salts, extracts, syrups and fragrant waters. These liquid dosage forms are made on the basis of individual need for prescription in pharmacies. They are stored no more than five days.

Dry medicines are sold in the form of a powder, which at home is brought to the required volume with water. Such preparations should be stored according to the manufacturer's recommendations: in the refrigerator or at room temperature.

In the preparation of a medicine the following principle is applied: first, the substances that dissolve most easily are triturated. Then, pre-homogenized poorly soluble components begin to be introduced. Vegetable raw materials are initially poured into powder with the addition of water.

If the composition of the mixture requires the addition of an alcoholic tincture to the aqueous solution, then it is recommended to do this in small portions to prevent precipitation.

Extracts

The peculiarity of these means is that the technology of manufacturing liquid dosage forms is reduced to the extraction of useful substances from medicinal herbs into a solvent and its subsequent concentration. Extracts are divided into three types:

• Liquid, which is dosed by volume;
• Dry (they are loose, the proportion of water - no more than 5%), are usually included in the composition of tablets;
• Thick (viscous in consistency, the proportion of water - no more than 25%).

Extracts can be applied orally or externally. They are stored up to five years in a package in a cool place without access to light, during which a precipitate is likely to fall out. Therefore, it is best to shake the extract before use.

Syrups

The preparation of liquid dosage forms in the form of syrups is reduced to the thickening of solutions of sucrose. In addition to the main active ingredients, they can include extracts and flavors. In their consistency, the syrups are thick, transparent and have a taste and smell characteristic of the preparation. These dosage forms are taken orally and are very much in demand in pediatrics for "sweetening" of children's medicines. Usually, the therapeutic effect of taking a syrup is higher than that of tablets. Store them in a container with a tightly screwed cover in a cool dark place. Shelf life of the syrup from the pharmacy is at least two years.

Solutions

This dosage form is absolutely transparent and sterile. The introduction of solutions is associated with a puncture of the skin. This medicine is made in the form of a syringe-tube, ampoules or a vial (glass or polyethylene). If the volume of the solution exceeds 100 ml, it is called "infusion". Such funds are usually injected into the vein by means of a dropper. It can be solutions for hemodynamics, adjustment of the balance of water and salts, detoxification, parenteral nutrition. There are also a wide range of action polyfunctional means. There is a rule: if you need to make a subcutaneous or intramuscular injection, then you can use both solutions and suspensions of a transparent type. Intravenous infusion is allowed exclusively transparent homogeneous solutions.

Solutions are usually prepared by diluting a liquid, solid or gaseous component in a solvent. This tool should be transparent and homogeneous, the presence of flakes, precipitation, and suspensions is unacceptable. In order to filter the solution, special paper or filters are added, folded into a glass funnel on a stand.

Most often, water is used as the solvent. If the solution is for injection, then it should be sterile, if it is meant for external use, it will also be boiled. If the drug substance does not dissolve in water, then ethanol or ether or oils can be used as a solvent (for injecting purposes, castor, sunflower, or external fish oil). Therefore, the solutions themselves are divided into alcohol, water, oil or ether.

There are also solutions designed for external (for wounds, mucous membranes, skin, etc.) and for internal use. They are homogeneous and transparent. Such products are produced in vials with a stopper in the form of a dropper, which is closed by screwing.

Storage solutions are made in the refrigerator or at room temperature. Usually this is described in the instructions to the drug.

Decoctions and infusions

These dosage forms are aqueous extracts from medicinal plants or solutions of a dry or liquid extract. Most often they are used inside. The production of liquid medicinal forms in the form of a decoction or tincture is usually carried out in a proportion of 1:10, that is, from 1 gram of vegetable raw material, 10 g of product is obtained. Taking into account the moisture absorption coefficient, water should be taken a little more. If you prepare an infusion of valerian or goritsvet, the proportion of 1:30 is observed. In the case of plants with a strong component, the ratio is 1: 400.

If concentrate is used, it is taken in the volume of the component by prescription.

The technology of making infusion and decoction is as follows:

• Drug raw materials are ground in water with room temperature water;
• The mixture is insisted on a water bath with continuous stirring 15 (for infusion) or 30 minutes (for decoction);
• Cooled to room temperature;
• Filter;
• Add water to the desired volume.

Decoctions of plants with a content of tannins (oak, cowberry, bearberry, etc.) should be filtered in a hot form, and from the leaves of the hay - only as it cools down completely. Infusions should be stored in the refrigerator for no more than two days and shaken before use.

Drops

This term means solutions, emulsions or suspensions, which are required to be dosed by drops. They are for internal ("Nitroglycerin") or for external (nasal, ophthalmic, ear) applications. On the bottle manufacturer usually installs a dispenser in the form of a droplet, which allows you to measure the right amount of medicine. The latter should be stored in a cool place without access to light.

Emulsions

These preparations are two insoluble liquids, one of which is an active substance (balm or oil) and the other is water. The appearance of the emulsion is homogeneous and opaque. They can be administered orally, externally or parenterally. If these liquid dosage forms (the recipes of which each pharmacist knows) were manufactured in a pharmacy, then the period of storage in the refrigerator is a couple of days. Industrial analogs retain their properties unchanged up to 1.5 years.

Baths

As ancillary procedures, accompanying the main treatment, doctors can prescribe a bath with special aqueous solutions. They have a directional effect on the body: relax, strengthen, tone, or fight bacteria. For procedures, it is possible to use extracts of various plants or mineral components. The most popular baths are from needles, lavender, and also oxygen or thermal baths.

Tinctures

Often used for treatment and these liquid dosage forms. Their characteristics are as follows: they can be painted and have a characteristic aroma. The tincture is prepared by alcohol extraction of the medicinal plant component. You can take them outside or inside, diluting with water or dripping on sugar. They have a longer shelf life than infusions and decoctions. However, the flask with tincture should be tightly closed and stored in the refrigerator without access to light. During storage, sediment may precipitate, so it must be shaken before use.

Suspensions

The production of liquid dosage forms in the form of a suspension is reduced to the distribution of powdery components in a liquid medium (oil, water, glycerin, etc.). They can be taken orally, externally, parenterally or intramuscularly. Immediately before use, the suspension should be shaken for 1 or 2 minutes. Store them in a refrigerator without access to light. Freezing suspensions is not allowed.

The choice of liquid medicines is really great. Sometimes this form of medication is a necessary measure. For example, children are much more likely to drink sweet syrup than a nasty pill. In addition, it is scientifically proven that this form of medicine works more effectively than its solid analog. The most important thing when treating liquid medicines is to follow the doctor's instructions, instructions, store it correctly and do not use it after the expiration date. If you decide to try herbal infusions, decoctions, tinctures or extracts, make sure that you do not have an allergic reaction to the ingredients of the composition of the remedy. For children prone to manifestations of dermatitis, manufacturers produce syrups and emulsions without sugar, so children should choose these drugs. Be healthy!