Soft dosage forms accompany a person from birth. The first meeting with them takes place in infancy, when the mother smears the delicate skin of the child with baby cream. From now on, we become inseparable with a variety of ointments, gels and pastes.
Soft dosage forms, the classification and characteristics of which will be presented below, are used in dermatology, ophthalmology, surgery, gynecology and other areas of medicine. They are very popular among doctors of various speci alties due to their ease of application, ease of preparation and long shelf life. The cosmetics industry is also poorly represented without all sorts of creams and ointments.
Ointments
It is best to start a story about soft dosage forms with ointments, since this association is the first thing that comes to mind for an average citizen. Ointments are medicines used for external use that contain less than a quarter of the dry matter of the total amount of the drug. They are obtained by mixing medicinal substances with bases that have a characteristicconsistency.
Soft dosage forms based on modern ointment bases (vaseline, lanolin, lard, wax, paraffin oils, etc.) are produced both on an industrial scale and in the form of piece, unique recipes. When choosing a base, the nature of the application, the therapeutic effect to be achieved, as well as the ability of the material to dissolve drugs are taken into account. So, for example, petroleum jelly only covers the skin, and lanolin is also absorbed into it.
Since ointments are used mainly for the treatment of dermatological diseases, in their manufacture they focus on local action. The doctor can write out the named drugs in an abbreviated or expanded form. The abbreviated form is used for finished drugs, as well as when the ointment contains only one drug component and is kneaded with vaseline.
Creams
It is impossible to imagine soft dosage forms without creams. The cream is a dispersed system that contains two or more components. Such a system, subject to the necessary thermal characteristics, retains a characteristic - less viscous than cream - consistency. Oil in water emulsion can contain up to 90% water and is designed to moisturize the skin. If the “water in oil” composition is used, then the components are taken in approximately equal proportions. Such a cream is necessary to soften and nourish the skin. May contain fats, waxes, mineral oils, silicones, alcohols and other substances. Cream making mixselected according to its purpose. It can have a warming or, conversely, cooling effect, relieve inflammation or promote the healing of a skin defect. Abbreviated prescriptions are used to prescribe the cream, while the base and amount of water are never indicated, leaving this question to the discretion of the pharmacist. Gel is a soft dosage form that can be used not only externally, but also subcutaneously and even orally. It has a jelly-like consistency and is usually colorless or clear. At the moment, this is the most common and popular form of release of medicinal substances. Distinguish between hydrophilic and hydrophobic gels. They are obtained by combining water, polymer powder (usually acid) and a neutralizer (soda, ammonia, carbonate, etc.). After thorough mixing, the mixture thickens and a gel is obtained. The viscosity of the resulting substance is measured in poise or centipoise. The variety and popularity of gels is explained by the fact that they are close in their characteristics to the hydrogen index of the skin, they are quick and easy to prepare, they are evenly distributed and do not clog pores. In addition, almost any medicinal substance can be added to the gel. Paste is one of the varieties of ointment, which has more powdery substances (about 65%) in its composition and, as a result, a thicker consistency. Therebyproperty, it stays on the skin for a long time and absorbs excess fluid, which makes it indispensable for achieving an anti-inflammatory effect. In most cases, neutral substances such as zinc powder, talc or starch are added to the paste to achieve the desired consistency. Recipes for pasta are written only in expanded form. An exception is made only for ready-made medicines of factory production. As a rule, after indicating the main ingredients and the base in the right proportions, they write: "Mix to make a paste." Official pastes are prescribed with the trade name. When listing soft dosage forms in pharmacology, we also mean liquid ointments or liniments. In fact, these are thick or jelly-like liquids that melt at a temperature of 37 degrees, so they must be rubbed into the skin on the damaged area. Any creams, ointments, gels or pastes that have characteristic features can be attributed to this type of medicine. Liniments have a short shelf life, so they are most often prepared directly at the pharmacy. For cooking, use a liquid base (sunflower, olive, linseed or vaseline oil). After specifying all the ingredients and their proportions, the recipe must indicate: "Mix to make liniment." This is important, since the ointment, paste and liniment may have the same composition. Softdosage forms in pharmacy production are also represented by candles. They, like liniments, melt at body temperature, but at the same time, under normal conditions, they are able to maintain a solid shape. Cocoa butter or alloys of paraffin and other inert substances are used as the basis for this type of medicine. Distinguish between rectal and vaginal suppositories. The former, as a rule, have a bullet-shaped or cone-shaped shape and weigh an average of up to three grams. Vaginal suppositories can be in the form of balls, ellipses or have a flat shape (pessaries). They also weigh three to four grams. Rectal suppositories are used both for the treatment of local processes in the rectum, and for general effects on the body, because the good blood supply to this section of the digestive canal allows substances to be quickly absorbed from the mucosa and have a systemic effect. When prescribing suppositories that are simple in composition, the active substance and its quantity are indicated. In the case of prescribing suppositories with a complex composition, only the commercial name and the number of units of the medicine are written. If a pediatrician or a gerontologist needs to prescribe a medicine in a soft dosage form to a patient, the prescription begins with the word: “capsules”. The shell in such medicines consists of edible gelatin. It is necessary for the active substance to reach the place of application unharmed. For example, not all drugs tolerate the acidic environment of the stomach well, so they need to be protected from such influences and at the same time retain the necessary properties. Pothe way of using the capsules are: They can have different contents: powders, granules, capsules, pellets, tablets, ointments or even live bacteria. Patches close the list of soft dosage forms. Recipes and their characteristics are quite simple. The patches are attached to the skin in order to have a local or general effect on the body. At a temperature of 20 degrees, this medicine is solid and is a mixture of rubber, fats, oils, antioxidants and active ingredient. Some plasters do not carry a therapeutic load, but are used to fix the edges of a wound, tighten the skin in a certain direction (in traumatology, cosmetology, dermatology) or to hold dressings and bandages in place. Since most medical patches have official names and are manufactured in a factory way, the abbreviated form is used when issuing a prescription, indicating only the trade name and size. Cosmetic and medical soap is somewhat different in composition. The latter is obtained after heating alkali and fat, while glycerol and other fatty acids are released from fats. Caustic sodium or potassium is used to catalyze the reaction. When adding water, the soap starts to foam and mechanically cleanses the skin. If the composition contains sedatives or disinfectants, then in addition to the main effect, it removesinflammation, dries up rashes or disinfects. Official medical soap is an odorless white powder that can be dissolved in water or alcohol. There is also a "green soap" - a translucent brown or greenish mass with a faint odor.
Gels
Pastes
Liniments
Suppositories
Gelatin capsules
Patches
Soap
