Skip to main content

What is an emulsion?

 Emulsion

Instead of a long definition, let's get to know this term in small divided forms.

  • Emulsion is a thermodynamically unstable system.
  • It consists of two immiscible liquids (one is generally water and another is oil)
  •  It consists of one phase dispersed into another in the form of globules/ droplets.
  • Either oil is dispersed in water (o/w) or water is dispersed into oil (w/o)
  • This system is stabilized by adding suitable emulsifying agent(s).
  • The liquid which is dispersed in the form of small globules is known as dispersed phase.
  • The liquid in which globules are dispersed is known as continuous phase.
  • For example- if paraffin oil is dispersed in the form of globules into water, paraffin oil is a dispersed phase and water is a continuous phase. This system is o/w i.e. oil in water emulsion.

The dispersed phase is also known as discontinuous phase or internal phase.

The continuous phase is also known as dispersion media or external phase.

1. While formulating an emulsion, a ratio of dispersed phase to the total volume of emulsion is determined. This ratio is known as phase volume ratio.

2. Emulsions intended for oral/internal administration are liquid emulsions.

3. Emulsions intended for external applications are referred as creams, lotions and liniments.

4. Globule size (diameter) in emulsions-
  • Coarse emulsions : 0.1 to 100 micrometers
  • Micro emulsions : less than 0.1 micrometer
  • Nano emulsions : less than 100 nanometers 
5. Internal phase/globule size of micro and nano emulsions is much smaller that it doesn't refract light and are transparent. (This transparency phenomenon depend of concentration of internal phase and dispersion of globules per unit volume).


Labels:

Comments

Post a Comment

Popular posts from this blog

UV-Visible spectroscopy: Basics

Ultraviolet Spectroscopy In this anaytical technique, ultraviolet radiations are used. Wavelength ranges of radiations: Visible light : 400 - 800 nm Near UV radiations : 200 - 400 nm Far/ Vacuum UV : below 200 nm Generally, we carry out UV analysis in near UV region of radiations. PRINCIPLE : Electronic transitions When a molecule absorbs UV radiations, the electronic excitation occur where electrons go from lower to higher energy state.  Electronic excitation causes the electron to go from electron bonding orbital to antibonding orbital. After some time electron returns to its original state (stable). While returning to its stable form (into bonding orbital) it releases excess energy. That energy is measured by the detector to access the wavelength (λmax) /absorption pattern. TRANSITIONS: σ → σ* (126-135 nm) n → σ* (180-200 nm) π → π* n → π* ALLOWED TRANSITION:  π → π* FORBIDDEN TRANSITIONS:    n → π* ENERGY OF VARIO...
Post a Comment
Read more

TABLETS

    Short notes on tablets I In this first article on tablets I am going to provide some important points regarding tablet formulation.   ü   I : Advantages, disadvantages, tablet defects and the excipients used in the formulation of tablets ü   II : Evaluationparameters and types & classes of tablets . Second part of this topic will be provided in the next post. So, for short notes on second point please refer the next post. Let’s start with the first point in this topic. ADVANTAGES OF TABLETS Oral route of administration is the most preferred route for the administration of drugs for their systemic effects. Tablets are mostly preferred for this due to following advantages: ·          Unit dosage forms ·          Greatest dose precision ·          Least content variability ·       ...
1 comment
Read more

CAPSULES I

Capsules are solid unit dosage forms in which the drug substance is enclosed within either a hard or soft gelatin shell. Hard gelatin capsules (HGC) : Hard Gelatin Capsules Contain two parts: a cap and other is a body. Widely used for the filling of powders, granules and pellets. Manufactured by dipping method, which involves steps: Dipping, Rotation, Drying, Stripping, Trimming & Joining . These are less plasticised than soft gelatin capsules. Soft gelatin capsules ( SGC): Soft Gelatin Capsules (Softgels) Referred as softgels as these are made from the more plasticised gelatin film. These are completely sealed dosage form & cannot be opened without destroying the shell. Generally, suspensions or the solutions of drug that do not solubilize the gelatin shell are enclosed in SGC. The most common methods for preparation of SGC is Rotary die process, Plate process, Bubble method, Accogel  (powder or granules filling). HARD GELATIN CAPSUL...
Post a Comment
Read more