Liquid dosage forms are dosage forms in liquid phase. They involve active pharmaceutical ingredients and excipients i.e. the inactive part in a liquid form. Liquid dosage forms are pourable pharmaceutical formulations which contain a mixture of active and inactive substances.
Types of Liquid Dosage Forms
There are two types of liquid dosage form based on the phases;
- Monophasic liquid form
- Biphasic liquid form
Monophasic Liquid Dosage Forms
Mono phasic form have only one phase. It’s a homogenous mixture of substance both the active and inactive ingredients in one phase.
Monophasic Liquid dosage forms include
- Mixtures: they are aqueous liquid preparations which contain suspended, insoluble solid substances intended for external use
- Linctuses: A syrup like medicinal formulation taken to relieve cough and sore throat.
- Droughts: A drought is an older term used to describe a liquid preparation formulated as a single dose in a volume which is larger than generally utilized in traditional mixture formulations.
- Elixer: elixers are sweetened hydro- alcoholic (water and alcohol) liquids for oral use.
- Syrup: A thick, sweet liquids made by dissolving sugar in boiling water. 85% of sugar is usually used.
- Drops: A liquid medication applied by means of a dropper.
- Lotions: A low viscosity topical preparation intended for application to the skin.
- Liniments: A liniment is a liquid dosage form that is rubbed into the skin in order to reduce pain or relieve stiffness. Liniments are solutions or mixtures of various substances in oil, alcoholic solution of soap or emulsions, intended for external use.
- Colloids: It has dispensed phase and dispersion medium. It is the mixture of two substances which one form the dispersed phase and the other forms the dispersion medium.
Gargles: They are aqueous solution employed for treating the pharynx and nasopharynx by forcing air from the lungs through gargle which is held in the throat. - Mouth wash: Liquid which is held in the mouth passively or swilled around the mouth by the contraction of the parietal muscles and movement of the head. It is used as antiseptic.
Throat paint: They are solutions or dispersions of one or more active ingredients intended for application to the mucosa of the throat or mouth. It is viscous due to high content of glycerin which sticks it to affected part for prolonged actions. - Douches: A douche is liquid dosage form introduced into the appropriate body cavity for cleansing purposes. They are referred to as irrigation possessing antiseptic.
- Enemas: They are rectal injections used to evacuate the bowel, influence the general system by absorption or to affect local seat of disease.
- Parenteral solutions: They are sterile liquid dosage form meant to be administered using syringes through venous route, muscular route or subcutaneous route.
- Solution: it is a homogenous mixture of two or more substances in a relative amount that can be varied continuously. A solution is a homogenous mixture of one or more solutes dissolved in a solvent.
- Magma: It is a suspension of inorganic solid such as clay in water where there is tendency for strong hydration and aggregation of solid giving rise to gel like consistency.
Biphasic Liquid Forms
They are heterogeneous mixtures of substances to form two phases.
Biphasic Liquid Dosage Forms Include:
- Suspension: It is a heterogeneous mixture that contain solid particles sufficiently large for sedimentation in the solvent like phase.
- Emulsion: It is a mixture of two substance especially oil and water that are normally immiscible but emulgent or emulsifying agent is added to mix them. They are of two types that is oil in water and water in oil emulsion