Products
Numerous active ingredients and pharmaceutical excipients are present in drugs as salts. They are also present in dietary supplements, in foods, medical devices and cosmetics. Various salts are available as open goods in pharmacies and drugstores.
Structure
Salts consist of positively and negatively charged atoms or compounds, that is, cations and anions. Together they form the ionic bond (ionic bond), which is based on electrostatic attraction. The best known representative is the table salt sodium chloride (NaCl), which is composed of the cation sodium (Na+) and the anion chloride (Cl-). Besides sodium chloride, countless other inorganic and organic salts exist (see below). Metal ions are usually cations and nonmetals form anions. Both can be monatomic or polyatomic. Ions can be not only singly charged, but also multiply charged. Because the charges balance out, a salt is neutral when viewed from the outside. In the so-called ion crystals, the ions arrange themselves in a typical lattice structure. In the salt crystal, each ion is surrounded by 6 counterions. The strength of the crystals is based on the electrostatic attraction of the ions to each other. Since this is strong, they have high melting points and boiling points (see below). Salts differ from molecules, which are uncharged and characterized by covalent bonds. The atoms in molecules share their electrons with each other.
Properties
Salts are often, although not always, highly soluble in water. An example of a poorly soluble salt is calcium carbonate (lime). They are good electrical conductors in solution or in the molten state, but not as crystals. Salts often exist as white or transparent and crystalline solids such as sodium chloride, but can be of any color. For example, potassium permanganate is purple and copper sulfate is blue. The melting point is typically high. It is 801 °C for sodium chloride. Therefore, unlike household sugar (sucrose), which is an organic molecule, salt does not melt and burn on the stovetop if it is spilled. Magnesium oxide even has a melting point of over 2800 °C. This also applies accordingly to the boiling points. Salts are formed, for example, when an acid reacts with a base. An example is shown below:
- NaOH (sodium hydroxide) + HCl (hydrochloric acid) NaCl (sodium chloride) + H2O (water).
Metals transfer electrons to nonmetals (see under redox reactions):
- 2 Mg: (magnesium elemental) + O2 (oxygen) 2 MgO (magnesium oxide)
Other reactions exist and salts also occur in nature, where they can be mined or obtained by another method.
Areas of application
In pharmacy:
- As active pharmaceutical ingredients and excipients, for food supplements.
- For the manufacture of active ingredient salts.
- For the preparation of magistral formulations.
Representative
The following are some examples of salts that are important in pharmacy (selection):
- Ammonium chloride
- Ammonium hydrogen carbonate (propellant salt)
- Ammonium nitrate
- Arginine aspartate
- Barium sulfate
- Bismuth subsalicylate
- Epsom salt (magnesium sulfate)
- Calcium ascorbate
- Calcium carbonate (lime)
- Calcium gluconate
- Ferric chloride
- Ferrous sulfate
- Ems salt
- Glauber’s salt (sodium sulfate)
- Staghorn salt (ammonium hydrogen carbonate)
- Potassium bromide
- Potassium carbonate
- Potassium chlorate (no longer used for medical purposes!)
- Potassium chloride
- Potassium dihydrogen phosphate
- Potassium hydrogen carbonate
- Potassium iodide
- Potassium nitrate (saltpeter)
- Potassium permanganate
- Catarrh dissolving salt mixture
- Copper sulfate
- Magnesium chloride
- Magnesium hydroxide
- Magnesium orotate
- Magnesium oxide
- Sea salt
- Sodium ascorbate (sodium salt of vitamin C).
- Sodium benzoate
- Sodium carbonate (soda)
- Sodium chlorate (no medical use!)
- Sodium chloride (table salt)
- Sodium citrate
- Sodium dihydrogen phosphate
- Sodium fluoride
- Sodium hydrogen carbonate (sodium bicarbonate)
- Sodium monohydrogen phosphate
- Salts of acids (e.g. acetates, citrates).
- Soaps (salts of fatty acids)
- Silver nitrate
- Active ingredient salts
- Zinc sulfate