What are the external liquid dosage forms?

External liquid dosage forms include:

1. Lotions
2. Creams
3. Gels
4. Solutions
5. Liniments
6. Sprays
7. Ointments

1. Solutions
- Clear, homogeneous liquid preparations containing one or more dissolved solutes in a solvent.
- Subtypes:
- Aqueous solutions: Solvent is water.
- Non-aqueous solutions: Solvent is not water, e.g., alcohol, propylene glycol.

2. Suspensions
- Heterogeneous mixtures containing finely dispersed solid particles suspended in a liquid vehicle.
- Subtypes:
- Flocculated suspensions: Particles form loose aggregates.
- Deflocculated suspensions: Particles are evenly dispersed.

3. Emulsions
- Biphasic systems containing two immiscible liquids (oil and water) emulsified and stabilized by surfactants.
- Subtypes:
- Oil-in-water (O/W) emulsions: Oil droplets dispersed in water.
- Water-in-oil (W/O) emulsions: Water droplets dispersed in oil.

4. Tinctures
- Alcoholic or hydroalcoholic solutions of plant or animal extracts.
- Prepared by maceration or percolation.

5. Syrups
- Viscous, concentrated solutions of sugars in water.
- Act as flavoring agents and suspending media.

6. Elixirs
- Clear, sweetened, hydroalcoholic solutions containing therapeutic agents.
- More palatable than syrups or tinctures.

7. Liniments
- Viscous, liquid preparations applied topically for external use.
- May contain analgesics, rubefacients, or antiseptics.

8. Lipophilic liquids
- Liquids that are nonpolar or have low water solubility.
- Used for topical application on skin or mucous membranes.
- Examples: oils, lotions, creams, ointments.