Solutions are classified on the basis of the following aspects (Figure 6.1):

Figure 6.1 Classification of Monophasic Liquid Dosage Forms

1. Route of administration
   • Oral solutions—through oral route
   • Otic solutions—instilled in the ears
   • Ophthalmic solutions—instilled in the eyes
   • Topical solutions—applied over the skin surface
2. Composition and uses
   •  Syrup—aqueous solution containing high concentration of sugar
   •  Elixir—sweetened hydroalcoholic solution
   •  Spirit—solution of aromatic materials in alcohol
   • Tincture/Fluid extract—solution prepared by extracting active constituents from crude drugs by use of alcohol or hydroalcohol
   •  Injection—sterile and pyrogen-free solution intended for parenteral administration