Paste is a soft dosage form for topical application. They are suspensions containing significant amounts of solid dispersed phase (at least 25%), which is evenly distributed in the base. The bases for pastes are used as bases for ointments, creams and gels. Unlike ointments, pastes contain a greater amount of powdered components and therefore have a thicker consistency, which allows them to remain on the surface longer. Liniments (or liquid ointments) are soft dosage forms for external use, which are thick liquids or gelatinous masses that melt at body temperature and are applied by rubbing into the skin. They may include ointments, creams, gels and pastes that have this property.

Suppositories are metered soft dosage forms that remain solid at room temperature and melt or dissolve at body temperature. Suppositories are used for insertion into body cavities. Soft gelatin capsules are a dosable soft dosage form consisting of a drug encapsulated in a shell. Drugs include masda, fats, vitamins, vitamin solutions, etc.

Plasters are a soft dosage form for external use that has the ability to adhere to the skin. Plasters have an effect on the skin, subcutaneous tissues and in some cases – a general effect on the body. At room temperature, the patch mass in appearance is a dense homogeneous mixture consisting of medical natural or synthetic rubber, fat-like substances, natural oils, fillers, antioxidants and medicinal substances. At body temperature, the patch mass softens and becomes sticky.

It should be noted that ointments, creams, gels, pastes and liniments form a separate group called “soft medicines”. Soft medicinal products (MMPs) in most cases are complex heterogeneous dispersed systems and have specific rheological properties. The quality, efficacy and safety of these drugs depend on the type and composition of the carrier base, the dispersed state of drug substances, the effectiveness of preservatives, production conditions, storage, etc.

Therefore, the general requirements for the quality of OTC drugs are very important, which are regulated in the general pharmacopoeial articles. OTC medicinal products for topical application (Unguenta) must be homogeneous in appearance and have specific rheological properties at the prescribed storage temperature. They are intended for application to the skin, wounds and certain mucous membranes and have either a local therapeutic, emollient or protective effect, or a general therapeutic effect when drugs penetrate the skin or mucous membranes. ILCs for topical application have a non-Newtonian type of flow and may be characterized by certain structural viscosity, pseudoplastic, plastic and thixotropic properties.

MLCs usually contain drug and excipients, which must be uniformly distributed in the dosage form. The excipients form a simple or complex base, which is produced separately or obtained during the manufacturing process of the IHR. The base, depending on its composition, may influence the bioavailability and therapeutic effect of the medicinal substance.