Structure and properties
Solutions are liquid preparations for oral use in which one or more active ingredients together with the excipients are dissolved in water or another suitable liquid (e.g., fatty oils, triglycerides). Oral solutions can also be freshly prepared from a powder or granules by adding the solvent (example: macrogols). Excipients include solubilizers (e.g., ethanol), thickeners (e.g., celluloses), acidity regulators (e.g., citric acid), sweeteners (e.g., sorbitol, saccharin), sugars, colorants (e.g., yellow orange S), preservatives (e.g., parabens, sodium benzoate), and flavor correctors (e.g., vanillin, flavorings). Solutions are marketed in single or multi-dose containers.
Effects
Solutions are especially suitable for children, the elderly, and patients with swallowing difficulties. Another advantage is that the dose can be adjusted individually.
Dosage
To measure the volume, a suitable device such as a dosing pipette, cup, or spoon is included with multi-dose containers. Solutions can also be administered with a dropper (as drops), with a dosing pump (by pumping movements), and with a pipette (by drawing up).
Disadvantages
The disadvantages of solutions include their lower stability compared with tablets, larger volume, and more difficult handling. Measuring the volume is a potential source of error. Some solutions must be used within a certain period of time after opening. If glass bottles fall to the floor, they will break.