DATE: 4th
December 2014
INTRODUCTION:
This test
is to determine the potency or content of ibuprofen. All types of tablets and
capsules are applicable to this test , except multivitamins and trace elements
as these contain more than one active ingredients . This test is important as
we have to determine the active ingredient in a tablet to standardize the
manufacturing process and prevent confusion happen among patients. In fact,
there are few ways to analyse the content of ibuprofen. For example, the
analysis is using chemical, physicochemical, microbiological and biological
method. Analytical methods involve absolute and relative methods.
EXPERIMENTAL
METHOD:
Apparatus :
Weighing
boat, weighing balance, mortar and pestle, two 250ml conical flasks, a 100ml beaker, hairdryer, filter funnel and
filter papers.
Materials:
20 400mg
Ibuprofen tablets, 50ml of Chloroform,
100ml of Ethanol, phenolphthalein solution, 0.1M NAOH solution.
Procedure :
1.
Twenty
400mg Ibuprofen tablets are selected randomly, weighed and powdered.
2.
A
quantity of powder containing 0.6g ibuprofen are extracted with 20ml chloroform
for 15 minutes and filtered through filter paper.
3.
The
residue are washed with 3X10 ml chloroform and the combined filtrate is gently evaporated just to dryness in a
current of air. The residue is dissolved in 100ml with ethanol (96%) previously
neutralized to phenolphthalein solution.
4.
The
solution is titrated with 0.1M sodium hydroxide to end point with
phenolphthalein solution as the indicator. The content of ibuprofen is
calculated if each ml of 0.1M sodium hydroxide is equivalent to 0.02063 g of
ibuprofen.
RESULTS AND CALCULATIONS:
1 tablet
of Ibuprofen = 400mg
20 tablets
of Ibuprofen = 20 x 400mg
= 8000mg
= 8g
Calculation to obtain 0.5g Ibuprofen
1 tablet
contains 400mg of Ibuprofen with other excipient. Hence, 20 tablets contain
8000mg (8g) Ibuprofen.
Total
weight of Ibuprofen powder which contains Ibuprofen and other excipient
= 9.2860g
0.5g8.0g =
x9.2860g
x =
0.9286g
End point
of titration with NaOH = 0.8ml
NaOH +
C13H18O2 → C13H17ONa + H2O
No. of mole of NaOH used in titration = MV1000 = 0.1 x 0.81000 = 8.00 x 10-5 mole
Based on
the equation,
1mole of
NaOH = 1mole of C13H18O2
8.00 x
10-5 mole of NaOH = 8.00 x 10-5 mole of C13H18O2
If of NaOH is equivalent to 0.02063g of Ibuprofen,
Then,
Ibuprofen contains in the solution for titration
= 8.00 x 10-5mole 1 x 10-4 mole x 0.02063g
=0.0165g
∴ the
content of ibuprofen is 0.0165g
Assay ,
0.0165/0.02063 X 100%= 80%
DISCUSSION:
0.8ml of
NAOH is obtained when colourless solution ( ibuprofen + chloroform +
phenolphthalein) turns to permanent pink solution.
0.0165 g
of ibuprofen is calculated from calculation above
According
to the result, assay of ibuprofen is 80% which is out of limit set by BP which
is 90-110% of stated content.
This might
due to errors occur during the experiment especially during filtration of
mixture of chloroform and 0.6g ibuprofen.
Improper
way of filtration cause some of the ibuprofen traps in the residue and during
evaporation of filtrate, some of the ibuprofen might blown away due to
different approaches of drying.
There are
other reasons to explain the error which are inaccurate weighing of ibuprofen
powders and segregation of components of ibuprofen formulation.
In order
to minimize the error or to get accurate result, more batches of samples have
to be done in this test, to get the average value or assay(%).
CONCLUSION:
In
conclusion, there are other tests to determine the drug in different
pharmaceutical formulation, same drug formulation should have uniform content
of active ingredient compared to standard content stated in BP. However, the
content of the tablets or assay(%) in this experiment varies. The deviation
from standard assay is 10%. Therefore, the uniformity of content of tablet is
essential to assessment of quality of dosage form design.
REFERENCES:
Ibuprofen
monograph.
2005. http://lib.njutcm.edu.cn/yaodian/ep/EP5.0/16_monographs/monographs_d-k/Ibuprofen.pdf
[ 9 November 2014
Formulation and Evaluation The Oral Tablets Ibuprofen2012. http://www.thepharmajournal.com/vol1Issue9/Issue_nov_2012/2.1.pdf [ 9 November 2014]
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