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Dosage Forms

Dosage forms - these are convenient for use conditions attached to drugs (physical state, geometric shape). The consistency of the dosage forms is divided into liquid, soft, solid and gaseous. To liquid dosage forms include solutions, tinctures, decoctions, tinctures, extracts, mucus, emulsions , suspensions , mixtures, saturation. To soft - ointments, pastes, liniments, suppositories, patches. To solid - powders, tablets, pills, dragees, fees. To gaseous - gases, aerosols. Solutions (Solutiones) are obtained by completely dissolving a solid drug or mixing liquid substances together. Solutions should not contain suspended particles and sediment. Distilled water (Aqua destillata) is most often used as a solvent, less often ethyl alcohol (Spiritus aethylicus 70%, 90%), oils. Solutions for external, internal use and for injections are used. Often solutions are prescribed drops (eye drops). Infusions (Infusa) and decoctions (Decocta) are water extracts from medicinal plant materials. They quickly decompose and therefore they are prepared immediately before being distributed to the patient and in small quantities (for 3-4 days). Tinctures (Tincturae) - liquid, clear, more or less colored alcohol, alcohol-water or alcohol-ether extracts of medicinal substances from vegetable raw materials. Extracts (Extracta) - concentrated extracts from vegetable raw materials; consistency distinguish liquid, thick (water not more than 25%) and dry (moisture not more than 5%). For the extraction of used water, alcohol, less ether and other solvents .

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Mucus (Mucilagines) - dispersed systems in which the smallest particles are suspended in a liquid; have the ability to cover with a thin layer of fabric and thus protect them from the effects of various stimuli. Mucus is often used with irritating medicinal substances.

Mixtures (Mixturae) - are obtained by mixing several drugs in water, alcohol and other solvents. They can be clear, cloudy and even with sediment, they should be shaken before use. Saturations are gas-saturated liquids. Injectable dosage forms include sterile solutions, emulsions, suspensions, as well as powders and tablets, which are dissolved before administration.

Ointments (Unguenta) - dosage forms that have a soft texture, intended for external use. Ointments are obtained by mixing various drugs (basis) with formative substances (constituens), called ointment bases. As ointment bases, oil refining products (petrolatum, paraffin, etc.), animal fats, and vegetable oils are used.

Pastae (Pastae) is a type of ointment with a powder content of at least 25% (similar in consistency to the dough), due to which they have good adsorbing and drying properties.

Liniments, or liquid ointments (Linimenta), are homogeneous mixtures in the form of thick liquids or gelatinous masses, melting at body temperature . Vegetable oils and animal fats are used as the basis for liniments.

Suppositories (Suppositoria) is a soft dosage form. At room temperature, they have a solid consistency, at body temperature melted. There are suppositories rectal (candles), vaginal and sticks. The most suitable base for suppositories is cocoa butter .

Powders (Pulveres) - solid dosage form for internal and external use, which has the property of flowability. Powders are distinguished: 1) simple - consisting of one substance; 2) complex - consisting of several drugs; 3) divided into separate doses and 4) undivided.

Medical capsules (Capsulae medicinales) are shells for powdered or liquid drugs used orally. They are starch (wafer), gelatin and glutoid.

Tablets (Tabulettae) - is a solid, convenient dosage form, obtained by the factory. They persist for a long time, mask the unpleasant taste of many drugs. Tablets can be coated with shells (Tabulettae obductae) made from wheat flour, starch, sugar, etc.

Pills (Pilulae) - solid dosage form for internal use in the form of balls prepared from a homogeneous plastic mass and drug substance.

Dragee (Dragee) - solid dosage form for internal use in the form of balls, obtained by building drugs on sugar granules.

Medicines (Species), or complex teas , are mixtures of dried, coarsely crushed portions of vegetable medicinal raw materials, sometimes with an admixture of other substances (salts, essential oils). Apply them externally ( poultices ) and inside (infusions, decoctions).

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Dosage forms - convenient for the reception and use of the state attached to drugs (geometric shape, state of aggregation).

There are several classification systems for dosage forms based on different principles. The oldest and least perfect classification - by the state of aggregation - divides the dosage forms into 4 groups: solid, liquid, soft and gaseous. Solid dosage forms include powders (Pulveres), tablets (Tabulettae), pills (Pilulae), dragees (Dragee), fees (Species), capsules (Capsulae); soft - ointments (Unguenta), pastes (Pastae), patches (Emplastra), candles (Suppositoria), balls (Globuli), sticks (Bacilli); to liquid - solutions (Solutiones), suspensions (Suspensiones), emulsions (Emulsa), saturation (Saturationes), infusions (Infusa), decoctions (Decocta), mucus (Mucilagines), liniments (Linimenta); to gaseous - gases, aerosols. The distribution of dosage forms for these groups among different authors does not match. This classification is convenient only for the primary separation of dosage forms. The aggregate state also determines the speed of the drug (liquid drugs act faster than solid ones); with the state of aggregation is also associated with the possibility of giving the drug one form or another. However, the state of aggregation says little about the technological processes that were used to obtain a particular dosage form.

A more advanced classification based on the method of use of drugs. According to this classification, dosage forms are divided into two groups: enteral, administered through the gastrointestinal tract, and parenteral, administered in addition to the gastrointestinal tract. Enteral dosage forms include drugs administered: 1) by the oral route (per os), including the most extensive group of dosage forms - liquid (solutions, suspensions, emulsions, infusions, decoctions, mucus), soft (pills), solid (powders, tablets dragee); 2) rectal way (per rectum) - candles. Parenteral dosage forms include drugs used: 1) on the skin (ointments, pastes, liniments, powders); 2) mucous membranes (ointments, powders, solutions, balls, sticks); 3) sublingually (tablets); 4) by inhalation (gases, aerosols); 5) by injection. Depending on the method of use, dosage forms have special names. For example, some liquid dosage forms are called mixtures, rinses, lotions, poultices, washes, injections, drops, etc., powders - powders, etc. This classification is mainly of medical importance, because the decision on choosing a route of medication The doctor takes, taking into account a number of circumstances and, above all, the patient’s condition. The strength and speed of the drug also depends on the route of its introduction.

From the pharmaceutical point of view, the dispersisological classification is more important, according to which all drugs are considered as physicochemical systems that have a certain internal structure and require a certain sequence of technological operations for their creation, that is, a general scheme of the technological process. A modern dispersion classification distinguishes two main groups: 1) free-dispersed systems; 2) coherent-dispersed systems. The first are the structureless systems in which the particles of the dispersed phase are not connected to each other in one continuous grid and freely move in the dispersion medium under the influence of thermal motion or gravity. Depending on the properties of the dispersion medium, the following free-dispersed systems are distinguished: 1) with a liquid dispersion medium (solutions, sols, suspensions, emulsions, combined systems, which include mixtures, drops, lotions, rinses, etc.); 2) with gaseous medium (gas mixtures, aerosols). The essence of technological processes is reduced to dissolution, peptization, suspension and emulsification.

In bonded-dispersed systems, particles are connected to each other due to molecular forces and form peculiar grids or frames in the dispersion medium. Depending on the dispersion medium and its connection with the phase of the dosage form of this group can be divided into the following systems: 1) bonded with a viscous or solid medium (ointments, pastes, suppositories, sticks); 2) frozen or recrystallized (pencils); 3) highly concentrated (pills, boluses); 4) bonded with gaseous medium (fine powders, tablets, granules). The essence of technological processes in the manufacture of drugs of this group is reduced to the phase dispersion, its uniform distribution and the creation of a structured system.

There are a number of requirements for medicinal forms: compliance with the physico-chemical properties of their constituent substances, durability, speed and completeness of therapeutic action, accuracy of dosing of medicinal substances, ease of administration, simplicity and speed of manufacture, etc. The greater advantages the dosage form has, the longer it remains in practice. Some dosage forms, which were widely used mainly in the last century, did not stand the test of time: Julepia - mixtures of medicinal substances with a solution of sugar in fragrant waters, lamellae (Lamellae) - gelatinous plates of gelatin, glycerin and medicinal substances, portions (Electuaria ) - mixtures of powders and extracts with honey or syrups, etc.

In recent years, new dosage forms have become widespread, especially abroad. Aromatized “dry suspensions” and “dry emulsions” —dried mixtures of medicinal, corrective, and emulsifying or suspending agents — (suspended or emulsified, they are produced immediately before administration) are stable and convenient during transportation. In this form, they release many antibiotics, hormones, vitamins. Much attention is paid to the creation of dosage forms with desired properties, i.e. with a specific therapeutic orientation. Such dosage forms include spensula - granules, covered with various shells, able to dissolve (disintegrate) in a specific environment and at a specified time. Many classical dosage forms are replaced by intensively and rapidly acting inhalation dosage forms, primarily aerosols (suspended solids and liquid particles in a gaseous medium), used with an inhaler.

The action of medicinal substances largely depends on the dosage form. Thus, atropine sulphate, administered orally in the form of a powder, is absorbed in 20-30 minutes, in the form of pills - in 30-40 minutes, and during injection - in 1-3 minutes. Insulin is completely destroyed by proteolytic enzymes, so it cannot be administered in oral dosage forms. Properly chosen form, thus, provides the best effect of the medicinal substance, and unsuccessful can reduce it, and sometimes even harm the patient. In this case, the methods of preparation of dosage forms are of great importance. For example, using different auxiliaries in the same form, you can get drugs with different strength, and sometimes different patterns of action. Introduction to the dosage form of minor amounts of surfactants contributes to a sharp increase in absorbability, and hence the strength of action of medicinal substances. The opposite effect - obtaining an inactive form - gives, for example, the replacement of pork fat with petroleum jelly in an ointment with potassium iodide, the effect of which can be manifested only after the absorption of the ointment.

Until recently, most dosage forms were manufactured in ex tempore pharmacies. At present, it has become possible to manufacture dosage forms according to approved standard prescriptions - the so-called finished dosage forms. The introduction of ready-made dosage forms into medical practice improved the quality of medicines, cheapened their production, dramatically relieved the pharmacies and accelerated the receipt of medicines by patients. Now, in pharmacies, only medicines are prepared according to individual prescriptions, as well as unstable dosage forms (tinctures, decoctions, mucus, emulsin, pills).

When choosing dosage forms, one should be guided by the physicochemical properties of the medicinal substance, the degree of its stability, the condition and age of the patient, the possibility of using the medicine depending on the surrounding patient's conditions, etc. Solutions, for example, are well dosed and taken, but many medicinal substances are dissolved unstable when stored; besides, solutions are inconvenient in the conditions of a traveling situation. Infusions, decoctions, mucus, emulsions are unstable, and therefore the prescribed quantities should not exceed three days' need (if stored in a cool place). Powders, tablets are dosed out more accurately than solutions, but they are not recommended for patients with severe inflammatory or ulcerative processes of the gastrointestinal tract, with a violation of the act of swallowing, for unconscious patients, young children. For children, preferred liquid dosage forms. For those suffering from chronic diseases, it is advisable to prescribe drugs in the form of tablets, dragees, pills, which are convenient to have with you and take in any conditions. When prescribing the drug inside it is necessary to take care of improving their taste. Patients who react negatively to oral dosage forms show rectal medication, which excludes such side effects as nausea, vomiting, etc.