Classification, Advantage And Disadvantage Of Pharmaceutical Biphasic Liquid Dosage Form

Biphasic liquid dosage form is one that has two phases. This system consists of a solid dispersed state and a liquid continuous phase that can be aqueous or oily and is stabilized by the addition of a suspended agent. In this preparation this phase is called ‘dispersed phase’ and the vehicle is called ‘dispersed medium.’ It’s also called internal phase or external phase respectively.

Biphasic liquid

These are commonly taken orally or through the parenteral route, and they are also used for external applications. The need for biphasic liquid dosage forms arises when the medications are poorly soluble in the solvent medium.

Read Also: What is a pharmaceutical mixture

Drugs can be either liquid or solid from the dispersed phase of the system.

Classification Of Particles Of Biphasic Liquid

They are categorised as:

1. Coarse particles, usually 1 - 100 microns in size

2. Fine dispersion containing particles of smaller 

size

3. And if the particles are in the colloidal range (< 1 Micron), they are termed magmas

Clarification Of Biphasic Liquid

Suspension

When the solid drug is distributed in the dispersion medium; the formed system is called a suspension e.g applications, enemas, lotion, inhalation, aerosols, eye drops. It is a system whereby insoluble solid particles of the drug are homogeneously dispersed in a liquid or semi-solid medium. 

Emulsion

When the liquid drug is delivered into the dispersion medium, the system form is called emulsion e.g application, liniment, lotion, enemas. It is a thermodynamically unstable system consisting of two immiscible liquid phases, one of which is dispersed as globules within the other and stabilized by an emulsifying agent. It has two types, water in oil type (w/o), and oil in a water type (o/w).

Advantages Of Biphasic Liquid Dosage Forms

1. It is used for the drugs that are insoluble in solution; therefore it is necessary to prepare an insoluble form of the drug, which is then administered as a suspension

2. It exhibits higher bioavailability rates than other dosage forms.

3. Suspension can offer prolonged action of the drug since solid particles must be dissolved before absorption.

4. Two incompatible ingredients/drugs can be included in a dose, one in each phase of the emulsion

Read Also: Overview of pharmaceutical monophasic liquid dosage form

Disadvantages Of Biphasic Liquid Dosage Forms

1. Not all drugs are compatible to formulate with biphasic form

2. It is bulky and therefore difficult to handle, transport and store

3. It is costly compared with the solid dosage form