Products
Many medicines as well as medical devices, chemicals and dietary supplements are sold as powders, for example painkillers, inhalants (powder inhalers), vitamins and minerals, salts, alkaline powders, probiotics, cold remedies and laxatives. Unlike in the past, powders have become less important as a form of medicine, but they are still used regularly.
Structure and properties
Powders consist of solid, loose, dry and more or less fine particles (particles) with a different shape, size and structure. They can be produced, for example, with a powder mill, with freeze-drying, by crystallization or with a mortar and pestle. They are finer than granules, which are composed of powder agglomerates. A distinction is made between simple and compound (mixed) powders. Powders may contain one or more active ingredients and excipients. Excipients include, for example:
- Dyes
- Sweeteners (eg, sorbitol, saccharin, sugar).
- Preservatives (e.g. benzoates)
- Lubricant (e.g. silicon dioxide)
- Flavor correctors
- Flavorings (e.g. vanillin)
- Diluents (e.g. lactose)
The preparation of powder mixtures and powder dilutions is called powder trituration (trituratio, trituration) in pharmacy. The pharmacopoeia distinguishes many different types of powders, for example, powders for oral use, for cutaneous use, for the preparation of infusion preparations and for inhalation (selection). Powders are available in single-dose, for example in paper bags or in multi-dose containers (e.g. can). In the pharmaceutical industry, they are of great importance mainly as starting materials for the production of other dosage forms. These include granules, tablets, capsules, suspensions, solutions, syrups, pastes, eye drops, and infusion and injection preparations. The reason for this is that many active ingredients and excipients are in powder form. As a separate dosage form, they are less important today than in the past. Examples:
- Powder + powder mixture granules tablets.
- Powder + water suspension or solution
- Powder + ointment base paste
Fields of application
Powders are commercially available for numerous indications (see above). They can be used internally or externally.
Dosage
Oral powders are usually taken with water or another liquid. This may produce a solution or suspension that must be shaken before use. Direct powders are taken directly from a small sachet into the mouth without water.
Advantages
Powders are characterized by increased stability over liquid dosage forms because they do not contain water. Powders for internal use are advantageous for patients with swallowing problems, such as the elderly and children. Due to the dissolving process, the active ingredients are already dissolved after preparation and can possibly be absorbed more quickly. Powders are flexible to dose – a smaller or larger amount can be measured out.
Disadvantages
Unlike other dosage forms such as tablets, many powders require a preparation step unless they are direct powders. This requires mixing the powder with water, for example. Powders can be more easily spilled and, because of their small particle size, can enter the lungs, where they can cause adverse effects. Some powders can also explode if they are finely dispersed in the air and reach an ignition source. Powders generally have poorer flow properties than granules. Lubricants can be used to improve the flow properties. For dispensing from a multi-dose container, for example, a spoon is required for measuring. Powders can absorb moisture and other substances and form aggregates (cake together). They should therefore be protected from moisture and stored well closed.
