Title
Analysis Of The Effect of Different Formulations On The Characteristics Of An Ointment
Objective
To analyze the effects of different ointment formulation
on the physical characteristics of the
ointment that is formed and the releasing rate of drug from the dosage form.
Introduction
An ointment is a
type of semi-solid preparation that is intended for application to the skin or
mucous membrane. It is an oily preparation that contains one or more active
ingredients dissolved or distributed homogenously. Ointments are usually used
as emollients or for the application of the active drug to the skin for
protective, therapeutic or prophylactic purposes. Ointments have some kind of
moisturizing effect and also good for dry skin. Sensitization is low because
they only have few active ingredients. The vehicle of an ointment is
known as the ointment base. The
choice of a base depends with the clinical indication for the ointment. A good
ointment must have an attractive texture, easily applied to the skin and
releases the active drug from the dosage form.
Generally, ointment consists of an active substance
(power or liquid) that is incorporated into an oily semisolid carrier. In
pharmaceutics, ointment preparation is used for local effects on the site of
application to increase skin hydration (emollient effects).
APPARATUS
|
Measuring instrument
|
1 weighing boat
|
1 100ml beaker
|
heater
|
1 set of glass slap & spatula
|
1 set of mortar & pestle
|
1 dialysis beg (10 cm),
|
2 strands of rope,
|
1 glass rod
|
water-bath
|
1 set of pipette (5ml) & pipette-bulb
|
1 plastic curvette
|
UV /Vis spectrometer
|
MATERIALS
|
Emulsifying wax
|
white soft paraffin
|
liquid paraffin
|
acetylsalicylic acid
|
distilled water
|
Procedure
1. A
emulsifying ointment (50g) is prepared using the formula stated below:
2. A
little bit of ointment formed is taken, put into a weighing bot and
labelled. The texture, clarity and colour of the ointment formed are compared
and explained.
3. The
acetylsalicylic acid powder (1.5g) is incorporated into 30g ointment which is
prepared by levigation technique (If needed, subtle the
salicylic acid with mortar and pestle.)
4. Acetylsalicylic
acid ointment is filled into the dialysis bag and is ensured both end is tied neatly.
5. The
bag is put into 100ml beaker that contain 50ml distilled water which is already
heated to 37‘C :
6. In
interval 5 minutes, pipette one aliquot sample (3-4 ml) and determine the
release salicylic acid using spectrometer UV –visible. Make sure distilled
water is stirred with glass rod before the sample is taken.
Results
and Discussions
From the experiment, we can compare the texture
of four types of ointments in three different aspects such as spreadibility,
greasiness and hardness.
The spreadibility
of ointment is depends on the amount of emulsifying fax. It can seen in the
spreadibility of emulsifying ointment I (emulsifying wax: 21g) is low compared
to emulsifying ointment IV (emulsifying wax: 9g). Besides, the presence of high
content of liquid paraffin (16g) in emulsifying ointment IV give a very greasy properties of ointment if compared to others. For hardness of the ointment, emulsifying
ointment I is the hardest and the hardness is decreasing to ointment IV which
is very soft. This is because of the amount of emulsifying wax used in the
ointment I is the highest. Apart from the contribution of emulsifying fax,
liquid paraffin also will affect the hardness of ointment. The lower the
content of liquid paraffin used, the harder the ointment formed. For the
comparison of transparency, the
physical appearance of the emulsifying ointment I is the most turbid and the
turbidity become less and less to the ointment IV. This may due to the content
of liquid paraffin. The higher the content of liquid paraffin in the ointment,
the lesser the degree of turbidity of ointment. For the appearance of the
ointment, all of the ointments formed are white in colour because of the liquid
paraffin which gives its colour.
2.
Plotted
the graph of UV penetration against time. Ointment I.
From the graph, we can notice
that the UV absorption for emulsifying ointment IV in the water bath at 37 oC
in order to evaluate the release of acetylsalicylic acid at body temperature is
proportional to the time. As the time passes, the amount drug released
increases. Therefore, this shows means that the drug is continuously being
released from the bag.
At
0 min, the value of UV absorption is 0.114. After 15 min, the UV absorption
value decreased and then kept increasing until 30 min. There is a value at 0
min and this could be due to the imperfectness and errors that would have
occurred during the preparation of the dialysis beg whereby some of the
ointment may have got stuck onto the dialysis beg. This would have caused the
presence of the drug in the beaker even at the beginning of the experiment. The
dialysis bag functions as a membrane for drug diffusion mimicking the natural
membrane found in the human body. From the graph, the results obtained may not
be perfect as there isn’t a constant increase in the drug release; furthermore
there was a slight decrease at 15 min. This is because of some errors that
could have occurred during the preparation of ointment. Probably there would
have been some bubbles present inside the dialysis bag due to improper filling
of acetylsalicylic acid ointment into the
dialysis bag which caused the slight decrease at 15 min or inconsistent drug
release.
Another
source of error could be during the sampling procedure whereby the sample was
not stirred well enough to ensure the even distribution of the drug in the
water inside the water beaker. Lastly, the process of using the spectrometer
too could have resulted in the deviations of the results. The clear side of the
plastic cuvette must face the UV light source. Failure in ensuring so would
have caused errors.
Theoretically,
the drug release should increase with the time. The water bath is used to
simulate a hypotonic condition as present in our body, where blood plasma
allows the diffusion of drug into it. The diffusion of drug will continue until
equilibrium is achieved.
1.
Plotted
the graph of UV penetration against time for the ointments which have different
compositions.
From the graph plotted above,
we can said that the UV penetration for all different type of formulation of
emulsifying ointment increase with time. This is because as the time increase,
the amount of ointment that is released into the water bath will also increase
as more Acetylsalicylic acid will diffuse out from the dialysis bag and into
water bath. When this sample is tested as time passes, the UV penetration will
be higher. However, for some formulation such as emulsifying ointment I, there
are slight decrease in UV penetration from tenth to fifteenth minutes . This
may have occurred due to the students having not stirred the distilled water
with glass rod before taking the sample and this would have caused uneven
distribution of Acetylsalicylic acid in the beaker. Sample with less
Acetylsalicylic acid will absorb less UV light. Hence, the UV penetration is
lower than it suppose to be.
Emulsifying
ointment III has the lowest UV penetration and the sequence increases with
emulsifying ointment IV, II and then I. Theoretically, the sequences of increasing UV penetration should be
emulsifying ointment I, II, III and IV. This is because emulsifying ointment I
has the highest amount of emulsifying wax whereas emulsifying ointment IV has
the lowest amount of emulsifying wax. The more the amount of emulsifying wax,
the more difficult it is for the Acetylsalicylic acid to diffuse out. This is
because the emulsifying wax tends to hold the
Acetylsalicylic acid from diffusing out from the dialysis bag and into the
distilled water. Hence, there will be less Acetylsalicylic acid available in
the distilled water and when these samples are tested with a spectrometer; the
UV penetration will become lower as there is less Acetylsalicylic acid
available to absorb UV light. However, in this experiment, we failed to get the
actual result and this happen may due to some errors that could have occurred
during the time the experiment was carried out. These errors include:
(a) There maybe some contamination of emulsifying
ointment in the outer membrane of the dialysis bag because after filling in the
ointment, student may forgot to wash their hand before touch the dialysis bag
again. This will causes the value of UV penetration become incorrect as some
Acetylsalicylic acid has dissolved in the distilled water.
(b) The
amount of emulsifying ointment filled into the dialysis bag may not be the same
for each group. Groups with more amount of ointment filled will have more
amounts of drugs diffuse out.
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 is the agent of the emulsifier to stabilize the formulation of oil in water emulsion and dissolving drugs that have the
features of oil and sedimentation problems with solvent. A high
content of emulsifying wax will result in physical characteristic that seen to
be less spreadibility, turbid and a ‘waxy crystalline’ ointment preparation. Emulsifying Wax also serves as a
surfactant to reduce surface tension thereby increasing the rate of drug
release. High
percentage of emulsifying wax and low content of liquid paraffin in formulation
will produce a rough and bigger crystal in the ointment preparation.
White
soft paraffin functions to give a white colour and greasy appearance to the
ointment preparation. It also contributes to the absorption of the drug into
the circulation by acting as a carrier through the skin.
Liquid paraffin is a colourless,
odourless fraction of higher liquid hydrocarbon obtained from petroleum. It
acts as softening agent and emollient to increase the ointment spreadibility,
smoothness, clear and greasy. Liquid paraffin decreases the release of the drug
from the bag. Liquid Paraffin also works to reduce the viscosity of the lubricant that caused by the use of high emulsifying wax, thereby stabilizes the
formulation. Liquid Paraffin is also used to
improve spreadibility. Liquid Paraffin can reduce the hardness of ointment. HLB value (hydrophilic lipophilic balance) surfactant is
optimum in the production of an ointment formulation and must be maintained at
a certain range of values. High composition of liquid paraffin will reduce the required amount of emulsifying wax.
Rate of drug release will be
increase by increasing the content of emulsifying wax whereas the high content
of liquid paraffin will decrease the rate of drug release. However, an optimal
ratio of emulsifying wax and liquid paraffin needed in order to produce a nice
physical appearance and good drug releasing ability ointment. The ratio for
emulsifying wax: white soft paraffin: liquid paraffin is 3:5:2.
Discussion
Hardness of the ointment is determined by the amount of emulsifying wax. When the composition of the emulsifying wax is high in the ointment, the level of hardness of ointment will also be increase. Features such as spreadibility and greasiness are depending on the amount of liquid paraffin in the ointment
formulation. The higher the composition of liquid paraffin, the higher the level of
spreadibility and greasiness of the ointment.
Emulsifying wax acts as an
emulsifying agent and solidified agent. It also can stabilize the ointment by
playing the role as surfactant. Besides that, it also increases the membrane
permeability towards the drug. Thus, increasing in the emulsifying wax in the
formulation will increase the diffusion of drug from ointment and the drug
release rate will increase. The wax is used to give ointment a solid shape and
make it easy to apply.
White Soft Paraffin is the carrier of an ointment and function in the absorption of drugs
by the skin's surface. Absorption of acetylsalicylic acid is more easily
with the action of carrier through the skin.
Liquid paraffin acts as softening agent and
emollient. High content of liquid paraffin will give fluidity, smooth, greasy,
high spreadibility and transparent properties of ointment preparation.
As time passes more Acetylsalicylic acid will
diffuse out from the dialysis bag. Therefore when sample is tested using
spectrometer, more Acetylsalicylic acid present tends to absorb more UV light
and hence the UV penetration value will be higher.
Drug release across a membrane, may it be a
dialysis bag membrane or the membrane present in the human body, is
proportional to time. This helps the diffusion of drug across our membrane into
the plasma at a constant rate until equilibrium is achieved and thus the drug
can exert its therapeutic effects.
The blood plasma is a paratonic solution which
has a hypotonic characteristic. This enables the diffusion of drugs into the
plasma and since the equilibrium value is maintained, incidence such as
crenation or hemolysis is prevented.
The drug formulation must be carried out very
meticulously to avoid any errors m=that may affect the drug diffusion in to the
plasma. These errors may lead to may serious effects especially if dealing with
potent drugs. Thus high quality control and good manufacturing practices are a
must during any drug formulation.
Conclusion:
Different
formulations in which the ointment content manipulated with emulsifying wax, liquid
paraffin and white soft paraffin can produce different desired characteristics, such as
viscosity, spreadibility, greasiness, hardness, and etc. Different
content of emulsifying wax and liquid paraffin will affect the rate of
diffusion of drug from the ointment prepared. High content of emulsifying wax
results in fast releasing rate of the drug. On the other hand, the higher the
content of liquid paraffin, the lower the drug releasing rate.
References
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
No comments:
Post a Comment