Tweens, which are polyoxyethylene derivatives of spans, are hydrophilic and have high HLB values (9.6-16.7). In order to form stable emulsions, an emulsifier or emulsifier mixture having HLB value equal to the HLB value of the oil phase should be used. HLB= E / 5 can be calculated with this equation.

Furthermore, what is HLB in emulsion?

Hydrophilic–lipophilic balance (HLB) is the balance of the size and strength of the hydrophilic and lipophilic moieties of a surfactant molecule. The HLB scale ranges from 0 to 20. In the range of 3.5 to 6.0, surfactants are more suitable for use in W/O emulsions.

Also Know, what is required HLB? Required HLB. • Like a nonionic surfactant has an HLB value, each lipophilic ingredient used in an O/W emulsion has an individual required HLB. • The required HLB for an oil(s) is the HLB value of the surfactant that will provide the lowest interfacial tension between your oil phase and your water phase.

Hereof, what is HLB method?

Hydrophile Lipophile Balance (HLB) is a way of measuring a substances solubility within water or oil. The HLB system was created as a tool to make it easier to use nonionic surfactants. The HLB system enables you to assign a HLB value to a surfactant and a HLB requirement to the application for that surfactant.

What emulsion means?

An emulsion is mixture of two liquids that would not normally mix. That is to say, a mixture of two immiscible liquids. By definition, an emulsion contains tiny particles of one liquid suspended in another. Chemically, they are colloids where both phases are liquids.

Related Question Answers

What is HLB range?

The hydrophile-lipophile balance (HLB) number is used as a measure of the ratio of these groups. It is a value between 0-60 defining the affinity of a surfactant for water or oil. HLB numbers are calculated for nonionic surfactants, and these surfactants have numbers ranging from 0-20.

What are the methods of preparing emulsions?

The methods commonly used to prepare emulsions can be divided into two categories A) Trituration Method This method consists of dry gum method and wet gum method. ? Dry Gum Method In this method the oil is first triturated with gum with a little amount of water to form the primary emulsion.

What is the HLB value of detergent?

HLB values of surface-active substances range from 0 to 40, but detergents typically have an HLB of 12–15. Nonionic detergents with a lower HLB (<10) are not water-soluble and are used as antifoaming agents or to emulsify water in oil, while those with a higher HLB (>16) are used as stabilizers.

How is HLB calculated?

HLB; According to Griffin, the amphiphilic molecule is the value obtained by dividing the weight percentage of the hydrophilic part by five. There is a balance between hydrophilic and lipophilic parts of amphiphilic molecules. This is expressed as the hydrophilic-lipophilic balance (HLB).

What are emulsifying agents?

Emulsifying agents are the substances that form a film around the dispersed globules or lower the interfacial tension in an emulsion.

Which compound is a natural emulsifying agent?

Lecithin in its natural state is known to be a very powerful emulsifying agent in promoting the O/W emulsions, whereas cholesterol exerts the reverse effect.

What is Span and Tween?

The Spans and Tweens are a range of mild nonionic surfactants providing formulating benefits in a number of Home Care applications. Croda's Span and Tween materials have long-standing food and pharmacopoeia approval with a safe history of use.

What are the types of emulsion?

There are two basic types of emulsions: oil-in-water (O/W) and water-in-oil (W/O). These emulsions are exactly what they sound like, as pictured below. In every emulsion there is a continuous phase that suspends the droplets of the other element which is called the dispersed phase.

How do you stabilize wo emulsion?

1. You can improve the stability of an O/W emulsion by increasing the viscosity of the water phase.
2. You have to adjust the pH of the water phase before you blend the two phases when making a W/O emulsion.
3. Basically, the chances of contamination are lower for W/O emulsions because the water phase is the inner phase.

How is the formation of emulsion minimized?

The simplest way to prevent the formation of an emulsion is to gently swirl instead of shake the separatory funnel. By swirling the separatory funnel the agitation that can cause the emulsion to form is reduced, but the surface area of contact between the two phases is maintained to allow for extraction to occur.

Which is primary emulsifier?

The primary emulsifier is generally a fatty acid or modified fatty acid with a lower HLB value. The secondary emulsifier has a higher HLB value, which can stabilize the emulsion and also wet the solid phase.

How do you make liquid paraffin emulsion?

Preparation B Liquid paraffin is added to the powdered arabic gum and mixed. According to 3: 2: 1 (oil: water: emulsifier) ratio emulsion water is added. Till characteristic emulsion sounds, mixture is mixed up quickly. The desired volume is completed by gradually adding the remaining mint juice.

How can you tell the difference between OW and WO emulsions?

When oil and water are mixed powerfully, they form either oil-in-water (o/w) or water-in-oil (w/o) emulsions. In o/w emulsions, oil is dispersed in a continuous water phase, while in w/o emulsions, water droplets are dispersed in oil.

What is oil in water emulsion?

When an emulsion is “oil-in-water,” oil is the dispersed phase that is distributed into the continuous phase, water. In a water-in-oil emulsion, the roles are switched. Milk is an example of an oil-in-water emulsion, while butter is water-in-oil.

What is emulsion PPT?

Emulsion is a dispersion in which the dispersed phase is composed of small globules of a liquid distributed throughout a vehicle in which it is immiscible Dispersion System Suspension is a two phased system in which a finely divided solid is dispersed in a continuous phase of solid, liquid, or gas. 5.

What is emulsion PDF?

Emulsions (Definition) ❖ An emulsion is a. thermodynamically unstable system consisting of at least two immiscible liquid phases one of which is dispersed as globules in the other liquid phase stabilized by a third substance called emulsifying agent.

What is HLB in pharmacy?

HLB System

HLB is the ratio of oil soluble and water-soluble portions of a molecule. HLB value is increased with increased hydrophilic nature, and decreased hydrophobic nature of surfactant. These scales have optimum efficiency for each class of surfactant, as seen in figure.

Who developed HLB system?

William C. Griffin

How do I choose an emulsifier?

Depending on the concentration of the oil phase (or water phase), you should try to find the most suitable emulsifier for that system. If a certain emulsifier works in your emulsion with 5% oil, it will very probably not be the best choice for another emulsion with 40% oil phase.

What is the application of HLB value in pharmaceutical preparation?

The hydrophilic–lipophilic balance (HLB) number system was used to optimize a compatible non-ionic surfactant, TDA (polyoxy- ethylene tridecyl ether) in formulations for two Beauveria bassiana strains, NI8 and GHA. The optimal HLB number for TDA was deter- mined on the basis of wetting times for conidial powders.

What does surfactant mean?

Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. The word "surfactant" is a blend of surface-active agent, coined c. 1950.

Why is HLB SLS 40?

Since SLS is more soluble in water than the oil, water is the continuous phase while the oil is the internal phase. In addition, SLS has a very high HLB value of 40 meaning it is water soluble and it prefers to form o/w emulsions.

What is the value of oil in water emulsifier?

Emulsifiers are characterized by their hydrophilic lipophilic balance (HLB), a number from 1 to 20 that indicates which tendency is more dominant. An HLB less than 6 favors water in oil emulsions; a value greater than 8 favors oil in water emulsions. Values of 7– 9 indicate good wetting agents.

What is the HLB value of Tween 80?

15

What is a surfactant and what does it do?

Surfactant, also called surface-active agent, substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. In the dyeing of textiles, surfactants help the dye penetrate the fabric evenly.

What is HLB value of Acacia?

The hydrophile-lipophile balance (HLB) of acacia has been determined in the presence of various ethylene oxide derivatives of sorbitan fatty acid esters. It was also found that different lots of acacia produced the same HLB values. A revised HLB value of 11.87 for acacia has been proposed.

Which of the following is the theory of emulsification?

Surface tensiontheory ? According to the surface tension theory of emulsification, the emulsifying agents cause a reduction in the interfacial tension of the two immiscible liquids, reducing the repellent force between the liquids and withdrawing the attraction of liquids for their own molecules.