Linctuses are viscous, liquid, oral preparations that are usually prescribed for the relief of cough. Linctuses are used for the treatment of cough.
Components of Linctuses
Active ingredients: They contain sedatives and expectorants.
Vehicles:
- Syrup IP – (67% w/w or 85% w/v sucrose solution) has a sweet taste, has a preservative action, viscous.
- Glycerol – Has demulcent action, sweet.
- Sorbitol – Used in preparations for diabetic patients, viscous.
- Invert syrup – Sweet and viscous.
Adjuncts:
Chemical stabilizers: Invert sugar has reducing action. This reduces the oxidative degradation of various colors and flavors. Hence color and flavors of fruit juices are better preserved in invert syrup.
Coloring agents: Coal tar dyes
- e.g. Amaranth – red color.
- e.g. Compound tartrazine solution – yellow color.
Flavoring agents:
- e.g. Tolu Syrup, Fruit flavors like lemon, and black current.
- e.g. Benzaldehyde Spirit – has an almond-like flavor.
Preservatives: Syrup (67% w/w) has high osmotic pressure and hence acts as a self-preservative. Other preservatives used are Chloroform spirit or Benzoic acid solution, etc.
Examples of Linctuses:
- Codeine linctus, pediatric B.P.C.
- Codeine linctus, Diabetic.
- Diamorphine linctus.
- Compound tolu linctus, pediatric.
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