Experiment 3 ointment

NFNF2263

PHARMACEUTICAL TECHNOLOGY 2

SEMESTER 2

SESSION 2012 / 2013

PRACTICAL REPORT 3

TITLE : EXP 3: Evaluation of different effects of ingredients towards the ointment formulation.

NAME        :                     1. LIM ANNE YEE (A131494)
                                             2. LIM GUCCI (A136085)
                                            3.LIM ZEN HUEI (A136194)
                                            4.TEH THIAN SIANG (A136169)
                 5. PUTERI EFFY NASTASHEA BINTI HOSLAM (A136042)

LETURER                     : DR HALIZA BINTI KATAS

FACULTY OF PHARMACY

UNIVERSITI KEBANGSAAN MALAYSIA

Title:

Evaluation of different effects of ingredients towards the ointment formulation.

Objective:

To study the effect of ointment composition towards the physical properties of the ointment and the rate of drugs release from the ointment formulation.

Introduction:

Ointment formulation is a suitable semisolid dosage form for the application on the skin. It is an oily preparation that contains one or more of the dissolved active drug or distributed homogenously. A good ointment should have attractive texture, easily applied onto the skin and release the active drug readily.

Usually, ointment consists of active ingredients (powder or liquid) which are incorporated into the oily semisolid carrier. In the pharmaceutical industry, the ointment preparation is used for topical treatment at the application site and to increase the moistures of the skin (emollient effects).

Apparatus:                                                                 Ingredients:

Weighing instrument                                       Emulsifying wax

Weighing boat                                                 White soft paraffin

100ml beaker                                                   Liquid paraffin

Heater                                                             Acetylsalicylic acid

1 set of cream and spatula                                          Distilled water

Mortar and pestle

Dialysis bag (10cm)

Thread

Glass rod

Water-bath

1 set of pipette (5 ml) and pipette-bulb

1 plastic kuvet

Spectrophotometer UV/Vis

Procedure:

1.      50g of Emulsifying Ointment was prepared for the following formulation:

Emulsifying Ointment	Ingredients (g)			Total (g)
	Emulsifying wax	White soft paraffin	Liquid paraffin
I	21	25	4	50
II	17	25	8	50
III	13	25	12	50
IV	9	25	16	50

1. 5 g of cream was taken and put into the weighing boat and was labeled. The texture, clarity and the color of the cream was described and compared.
2. 1.5 g of Acetylsalicylic acid powder was incorporated into 30 g of cream which was prepared by levigation technique.
3. Acetylsalicylic acid was filled into the dialysis bag and the two side of the bag was tied.
4. The bag was put into a beaker (200ml) filled with distilled water (100ml) which was heated to 37°C.
5. Every 5 minutes, one aliquot sample (3 – 4 ml) was pipette and the release of Acetylsalicylic acid from the cream base was determined by using spectrometer UV-visible. The distilled water was stirred with glass rod before the sample was taken.

Results  :

Time(min)	UV absorption at 310 nm
0	0
5	0.036
10	0.040
15	0.065
20	0.082
25	0.109
30	0.122
35	0.141
40	0.177
45	0.180
50	0.225
55	0.246
60	0.250

Discussions:

1.      Compare the physical characteristics of the ointments and explain.

Group	Material (g)				Texture of ointment			Clarity	Colour
	Emulsifying wax	White soft paraffin	Liquid paraffin	Spreadibility		Greasiness	Hardness
5	21	25	4	Most difficult		Least greasy	Hardest	Turbid	White
6	17	25	8	Difficult		Relatively greasy	Hard	Turbid	White
7	13	25	12	Intermediate		Greasy	Soft	Turbid	White
8	9	25	16	Easy		Most greasy	Softest	Turbid	White

The ointments that are formulated by each group are the same in the composition of white soft paraffin however the composition of the emulsifying wax and the liquid paraffin are different for each group. The quantities for both of these materials are varied to make up a total amount of 50g of ointment. All the ointment that is formulated is white in colour and turbid. The degree of the turbidity of the ointment depends on the amount of emulsifying wax added to the formulation. As the amount of the emulsifying wax increased in the formulation it will be easier for the ointment to spread upon application. The greasiness of the formulation also increases as the amount of emulsifying wax increases in the formulation. The quantity emulsifying wax in the formulation will also cause the hardness of the ointment to vary. The lower the quantity of emulsifying wax, the softer the ointment produced.

2. Plot a graph of UV absorption versus time. Give reason.

In this experiment , the dialysis bag is resembled to the phospholipid bilayer of the cell membrane of human where the absorption occurs across the membrane into the distilled water which is resembled to the blood plasma. The temperature of distilled water is maintained at 37ºC which is the temperature of human body.

The amount of drug absorbed into the blood circulation is represented by the concentrations of the drug in the distilled water. The UV absorption represents the concentration of the drug that crosses the membrane and reaches into  the distilled water.

In theory, the UV absorption is proportional to the time of the release of salicyclic acid across the membrane to distilled water. The gradient of the graph shows the rate of drug release across the membrane of dialysis bag.

The graph shows that as the time increases, the concentration of the salicyclic acid in the distilled water is increasing. Along the time until a particular point, the gradient of the graph decreases thus the releasing rate is reduced. Along the progression of the experiment, the concentration of salicyclic acid in the dialysis bag and the distilled water become isotonic because the salicyclic acid keeps moving into the distilled water. The gradient of graph decreases because the salicyclic acid diffuses into and out of the membrane of dialysis bag in an equilibrium state. At the late stage, the releasing rate increases. This may be contributed by the experimental error such as leakage of the drug whereby the thread is not tight tightly enough or  the distilled water is stirred too vigorously.

3.      Plot graph UV absorption against time for the ointment formulation with different composition. Compare and discuss the results.

From the graph above, the formulation 1 has the highest concentration of acetylsalicylic acid in the distilled water. Theoretically, low concentration of acetylsalicylic acid in the distilled water should be shown. Physically, formulation 1 ointment is harder than the other ointments. Formulation 1 should show slow release rate due to the high proportion of the emulsifying wax and low proportion of liquid paraffin. Usually hydrophilic acetylsalicylic acid can disperse uniformly in the ointment, due to high proportion of the emulsifying agents (emulsifying wax). However, the oil phase (liquid paraffin and soft paraffin) is not enough for the acetylsalicylic acid to diffuse through the membrane. Hence concentration of acetylsalicylic in the distilled water should be low.

            From the book Differential diagnosis in dermatology written by Richard Ashton, Barbara Leppard, the ideal formulation of ointment has the percentage of emulsifying wax, white soft paraffin and liquid paraffin at 30%, 50%, 20% respectively.

      The graph shown indicates that formulation 2 has higher concentration of acetylsalicylic acid in distilled water than formulation 3. Theoretically, as the amount of emulsifying wax decrease and amount of liquid paraffin increases, the acetylsalicylic acid can diffuse through the membrane better which means that isotonicity can be achieved between ointment and the surrounding distilled water in a faster way. In formulation 2, the percentage of emulsifying wax, white soft paraffin and liquid paraffin should be 34%, 50%, 16% respectively. Meanwhile, in formulation 3, the percentage of emulsifying wax, white soft paraffin and liquid paraffin should be 26%, 50%, 24% respectively. Both formulations shows only 4% difference with the ideal formulation. Thus, these formulations encourage the diffusion of drugs into the distilled water through the membrane.

      Formulation 4 has the lowest concentration of acetylsalicylic acid in distilled water. Although there is a high amount of liquid paraffin to assist in the diffusion of acetylsalicylic acid, but insufficient emulsifying wax causes acetylsalicylic acid unable to disperse properly in ointment. Therefore, acetylsalicylic acid has low concentration in distilled water.

      As the time goes on, the concentration of acetylsalicylic acid in distilled water gradually increases for every formulation. However, in formulation 2 there is a slight decrease in concentration during 30 minutes to 35 minutes. This is due to uneven stirring or absence of stirring before taking out the volume, the concentration of acetylsalicylic acid is unevenly distributed in the distilled water. Hence, the volume taken out maybe less concentrate than the previous concentration.

4.      What is the function of each ingredient using in the preparation of ointment. How the usage of different content of Emulsifying Wax and Liquid Paraffin influence physical characteristic of the ointment formulation and its drug releasing rate?

Emulsifying Wax	Substance added to an emulsion to prevent the coalescence of the globules of the dispersed phase. They are also known as emulgents or emulsifiers. They act by reducing the interfacial tension between the two phases and forming a stable interfacial film. It can increase the water solubility of the ointment.
White Soft Paraffin	It is reserved for products with colourless, white or pale ingredients. It inhibits water loss from the skin by forming a greasy layer, and this in turns improves the hydration of the skin in dry scaly conditions.
Liquid Paraffin	Liquid paraffin increases the lipophilicity of ointment, so that it can penetrate the membrane. It also used to reduce the viscosity of the ointment.
Acetylesalicylic acid	An active ingredient used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication.

Liquid paraffin increases the liphophilicity of ointment, so that it can penetrate the membrane. Emulsifying wax increase the water solubility. The higher the amount of emulsifying wax, the greater the capability of the ointment to hold water. The greater the amount of the liquid paraffin, the higher the lipophilicity, the greater the penetration of the drugs .

Conclusion:

Physical properties of the ointment and the rate of release of drug from the formulation can be influence by different composition of the ointment. Thus, the components of the formulation must be in suitable proportion to produce a drug which has desired therapeutic effect.

References:

1.      Aulton, M.E. 2002. Pharmaceutics: The science of dosage form design. Edinburgh: Churchill Livingstone

2.      Florence,A.T. & Attwood, D. 1998. Physico-chemical principles of pharmacy. 3rd Ed. New York: Macmillan.