Title
Content
of ibuprofen (assay)
Date of experiment
4th
December 2014
Objective
To analyze the content of
Ibuprofen in the tablet.
Introduction
A tablet does not consist solely
of active ingredient but in fact it is a mixture of active ingredients and
excipients, this is to avoid overdosing. Besides, excipients are also added to
enhance the flow properties, disintegration, rate of dissolution or to be said
that to increase the bioavailability. Content of active ingredient in certain
oral dosage form, such as tablets and capsules, can be determined using the
standard assays that are found in British Pharmacopoeia.
Thus, a tablet with a
weight of 500mg contains excipients such as diluents, disintegrant, binding
agent, lubricant, glidant, adsorbents depend on what kind of dosage form and
how the drug works. In this experiment, Ibuprofen tablet 400mg is used to test
its content of active ingredient.
Materials
0.6g of Ibuprofen powder,
chloroform, ethanol (96%), phenolphthalein solution, 0.1M sodium hydroxide.
Apparatus
100mL beaker, 250ml conical
flask, filter paper, filter funnel, weighing machine, weighing boat, hair
dryer, burette, 100mL measuring cylinder.
Procedures
1.
20
Ibuprofen tablets are selected at random and are weighed and crushed into
powder form.
2.
Powder
containing 0.5g of Ibuprofen is extracted by 20mL chloroform for around
15minutes and it is filtered through a
filter paper.
3.
The
residue is washed with 3 x 10mL chloroform and the filtrate is evaporated just
to dryness in a current of air. The residue is then dissolved into 100mL of
ethanol (96%) which is neutralized with phenolphthalein solution.
4.
The
solution is titrated with 0.1M sodium hydroxide to end point with
phenolphthalein solution as an indicator. The content of Ibuprofen is
determined if each mL of 0.1M sodium hydroxide used is equivalent to 0.02063g C13H18O2.
Results
Titration:
Initial reading of 0.1M sodium
hydroxide = 25mL
Final reading of 0.1M sodium
hydroxide = 33.2mL
Volume of 0.1M sodium
hydroxide used = 8.2mL
Given that 1mL of 0.1M sodium
hydroxide is equivalent to 0.02063g C13H18O2,
So, the weight of Ibuprofen in
the tablet is 8.2 x 0.02063g = 0.1691g.
From the experiment, the
percentage of Ibuprofen content is
=
0.1691g/0.5000g x 100%
= 33.82%
Discussion
In order
to formulate a successful dosage form, the tablets should contain 90% ~ 110% of
the labelled Ibuprofen according to the standard stated in British Pharmacopoeia(B.P).
Any value outside the range of the standard is considered as a failed
formulation in the B.P test for content of active ingredient. This experiment
is used to analyze the content of Ibuprofen in the tablet. From the results we
obtained, it only contains 33.82% of
Ibuprofen if compared to the labeled products. This value is not in the range
of the standard of B.P. Therefore, this formulation has failed the B.P test.
The test is carried out to achieve the uniformity of content in tablet.
The value
that we get is not in compliance with the standard in B.P due to some errors
occured throughout the experiment. First reason is that the filtrate did not
evaporate to dryness or excess heat supplied that caused the degradation of
Ibuprofen content. Secondly, parallax error may occur when taking the reading
of burette during titration, in which the eye level of observer is not parallel
to the level of meniscus. Thirdly, the burette tips may contain air bubbles.
Lastly, the improper filtration of extract through the filter paper will
contribute to an inaccurate result. Chloroform is a volatile liquid, hence some
of it may evaporate, leading to the decrease in the amount of filtrate
produced.
Conclusion
The content of Ibuprofen is
0.1691g. The tablets that we tested contain 33.82% of Ibuprofen which do not
comply with the standard of B.P which is 90% ~ 110% of the content. Therefore,
the tablets have failed the B.P test due to the inconsistent content of
Ibuprofen in the tablets.
References
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