EXPERIMENT 1: EMULSION

Title:

The effects of differences characteristic of active ingredient in formulation of emulsion

Objectives :

1. To determine the HLB surfactant on the stability of emulsion
2. To determine physical effect and stability on emulsion formulation due to used of differences content of      emulsifying agent.

Introduction:

Emulsion is a one component two phase system which involve mixtures of two immiscible liquids.An emulsion containing tiny particles of one liquid suspended in another.Emulsion are formed from the component liquid either by spontaneously or by mechanical such as agitation.There are two types of emulsion which is oil in water emulsion(o/w)  and water in oil emulsion(w/o). Stable emulsions can be formed from two immiscible liquids when an emulsifier is used. Such emulsions do not separate out after a change in conditions like temperature or over time.HLB (hydrophilic-lipophilic balance) is a method that used to determine quantity and types of surfactant that used in formulation of emulsion.Emulsifiers containing both  hydrophilic head that composed of water soluble functional group and a lipophilic tail that composed of fatty acid.Emulsifier showing greater solubility in water is better for oil in water emulsion and vice versa.So that,the lower HLB value emulsifiers be better in water in oil emulsion as thet are more lipophilic while the higher HLB value emulsifiers are more hydrophilic.

Procedure

1. 8 test tubes were labeled and straight line were drawn 1 cm from the bottom of each of the test tubes.
2. Then, 4 ml of oil (Table 1) and 4 ml of distilled water were added into each of the test tubes.

                                                          Table 1

3. Span 20 and Tween 80 (Table 2) were drops into the mixture of oil and water in each of the test tubes. The test tubes were closed and the mixture was mix using Vortex mixture tool for about 45 seconds. The times taken for the interface to achieve the 1 cm line were recorded. The HLB values for each sample were determined.

                                                                      Table 2

4. 1g of the emulsion that is formed in each test tube was weight in the weighing boat and Sudan III (0.5%) solution were drops to the emulsion. Dispersion of color in the samples were described and compared. A little sample for each of the test tubes was spread on a microscope slide and observed under a light microscope. The shape and size of globular that are formed were drawn and compared.

5. By using the wet gum method, a formulation of Mineral Oil Emulsion were prepared using the formula below:

INGREDIENTS	AMOUNT USED
Mineral oil Acacia Syrup Vanillin Alcohol Distilled water, qs	(Refer to table 3) 6.25 g 5 ml 2 g 3 ml 50 ml

Wet Gum Method

     a)      Acacia is added to the mortar and triturated with water until smooth gum is formed.

     b)      The oil is added to the mixture while triturating continuously until a smooth emulsion is obtained.

6. 40 g of emulsion that are formed was added into a 50ml beaker and homogenizing process was done for 2 minutes using a homogenizing device.

7. 2 g of emulsion that are formed was taken before and after the homogenizing process and put into the weighing boat and labeled. A few drops of Sudan III solution was added into the emulsion and smooths it. The texture, consistency, shape, degree of greasiness and dispersion color of samples was described and compared under light microscope.                                                                                
8. Viscosity of the emulsion (15 g in 50 ml beaker) that are formed after the homogenizing was determined by using the viscometer equipment that has been calibrated at all times by using the "Spindle" type LV-4. The samples are then exposed to a temperature of 45 ⁰C (water bath) for 30 minutes and then at a temperature of 4 ⁰C (refrigerator) for 30 minutes. Viscosity of the emulsion after exposure to temperature cycles completed was determined and emulsion reaches room temperature (10-15 minute).
9. 5 g of emulsion that have been homogenized was added into a centrifuge tube and it is centrifuged (4500 rpm, 10 minute, 25 ⁰C).  The resulting high separation was measured and the ratio of the separation was determined.

Results and discussion

Group 1 and 5- Palm oil

Group 2 and 6- Arachis oil 

Group 3 and 7- Olive oil  

Group 4 and 8- Mineral oil 

HLB surfactant 1  (Span 20) = 8.6;   HLB surfactant 2   (Tween 80) = 15.0

HLB value= (quantity of surfactant 1)(HLB of surfactant 1)+(quantity of surfactant 2)(HLB surfactant 2)

                                             quantity of surfactant 1+ quantity of surfactant 2

Example of calculation:

            

 HLB  =  (15)(8.6) + (3)(15)

                          15+3

                        =   9.67

        

               For palm oil, the HLB value that can give stable emulsion is 9.67, 10.73 and 11.34. This means that the stable emulsion of palm oil can be prepared by adding 15 drops of Span 20 and 3 drops of Tween 80 or 12 drops of Span 20 and 6 drops of Tween 80 or 12 drops of Span 20 and 9 drops of Tween 80 . For arachis oil, the HLB value that can give stable emulsion is 9.67,10.73 and 11.34. This means that the stable emulsion of palm oil can be prepared by adding  15 drops of Span 20 and 3 drops of Tween 80 or 12 drops of Span 20 and 6 drops of Tween 80 or 12 drops of Span 20 and 9 drops of Tween 80. For olive oil, the HLB value that can give stable emulsion is 9.67, 10.73,11.34,12.44 and14.08. This means that the stable emulsion of palm oil can be prepared by adding 15 drops of Span 20 and 3 drops of Tween 80 or 12 drops of Span 20 and 6 drops of Tween 80 or 12 drops of Span 20 and 9 drops of Tween 80 or 6 drops of Span 20 and 9 drops of Tween 80 or 3 drops of Span 20 and 18 drops of Tween 80 . For turpentine oil, the HLB value that can give stable emulsion is 9.67,10.73 and 11.34. This means that the stable emulsion of palm oil can be prepared by adding 15 drops of Span 20 and 3 drops of Tween 80 or 12 drops of Span 20 and 6 drops of Tween 80 or 12 drops of Span 20 and 9 drops of Tween 80.

          Therefore, different oils with different HLB values require different combination of surfactants in order to produce stable emulsion.

          Generally, the emulsion of each oil will separate into two phases within shortest time if the surfactants (Span 20 or Tween 80) are not used in the formulation. This is due to the absence of the surfactant which play a role in dispersing the oily phase into the aqueus phase or otherwise. If a single susfactant is used in the emulsion formulation, the product produced is not so stable compared to the emulsion with combination of 2 surfactants.

           In fact, surfactant is used in formulating the emulsion to stabilise both the oil and aqueus phases which are not immiscible. Micelle consists of the hdrophillic head and hydrophobic tail. It will try to keep the hydrophobic drug particles in the core of the micelle with the tail points inward to the center of the micelle and the head will remain in the aqueus phase. The adsorbtion of the surfactant at the interface between the two immiscible phases will lower the interfacial tension, the process of emulsification will be made easier and the stability may be enhanced.

           However, there may be some experimental errors that can make the results inaccurate. The surfactants added are measured by drops which is not so accurate. There maybe also paralax errors when observing the phase separation in the test tubes. Different observers for different test tube may also resulted in inacurate result.

2.

Sample	Observation
Picture 1	Combination large and small globules size Irregular shape of globules
Picture 2	Globules size is too small
Picture 3	Combination large and small of globules size Regular shape of globules Less number of globule formed
Picture 4	Combination large and small of globules size Regular shape of globules
Picture 5	Small size of globules Regular shape of globules More number of globules formed
Picture 6	Small size of globules Regular shape of globules More number of globules formed
Picture 7	Small size of globules
Picture 8	Combination large and small size of globules Irregular shape of globules

Compare the physical characteristic of the emulsion Mineral Oil formed and explain. What is Sudan Test III? Compare the color dispersion in the emulsion formed and explain.

                Sudan solution is used to show the shape and physical characteristic of oily emulsion. It can show the emulsion whether is oily-in-water emulsion or water-in-oil emulsion by comparing the amount of the globules in red color and the colorless globules. Sudan solution, which is red in color, is dissolved in the oily phase in the emulsion. This makes the oily globules red in color.

            A w/o preparation will have a greasy texture and often exhibits a higher apparent viscosity than o/w emulsions. After homogenization, the w/o emulsion is converted to o/w emulsion. The oily phase will be broken down into small globules. The texture of the mineral oil occurs in a smoother and homogenous state. The color dispersion is more uniform. This shows that the globule is dispersed equally. Besides, the globule size is significantly smaller than that before homogenization. The homogenization process makes the oily globules disperse evenly and becomes more stable in the aqueous phase.