Experiment 5
Content of ibuprofen (assay)
Date: 9/12/2013
Objective: To compare the amount of
ibuprofen theoretically and experimentally.
Apparatus: conical flask, beaker, filter funnel, dryer,
retort stand, pipette, white paper, measuring cylinder, pestle and mortar,
filter paper
Materials: ibuprofen tablets (20), chloroform,
ethanol, phenolphthalein solution, 0.1M sodium hydroxide
Methodology:
1.
20 Ibuprofen Tablets were grinned using
pestle and mortar until became powder.
2. The
powder was weighed and 1.0409g was extracted which containing 0.5 g ibuprofen
3. The
extracted powder was dissolved into 20 ml chloroform for 15 minutes.
4. The
dissolved powder was then titrated through filter paper.
5. The
residue was washed three times with 10 ml chloroform.
6. The
filtrate was dried gently using dryer.
7. Then,
the dried filtrate was dissolved with 100ml ethanol and 2 to 3 drops of
phenolphthalein solution was added as an indicator.
8. The
solution was titrated with 0.1M sodium hydroxide to end point, where the
solution turned pink or purple.
9. The
content of ibuprofen was calculated where each ml of 0.1M sodium hydroxide is
equivalent to 0.02063 g of C13H18O2.
Calculation:
20tablets = 8.32685g of total amount = 4g of ibuprofen
= 1.0409g of
total amount = 0.5g of ibuprofen
1.0409g of total amount of tablet was
titrated with 0.1M of sodium hydroxide.
Volume of 0.1M of sodium hydroxide used
= 23.3ml
1ml of 0.1M of sodium hydroxide =
0.02063g of ibuprofen
23.3ml of 0.1M of sodium hydroxide =
0.48068g of ibuprofen
Theoretically,
= 1.0409g of
total amount = 0.5g of ibuprofen
From experiment,
= 1.0409g of total amount = 0.48068g of ibuprofen
Therefore,
Percentage of standard deviation is [100
– (0.48068g of ibuprofen / 0.5g of ibuprofen x 100)] = 3. 86%
Discussion:
From the experiment, we took 20
ibuprofen tablets that have overall weight of 8.3268g which contain 4g of
ibuprofen. Then, from that we only take 0.5g of ibuprofen which is equal to
1.0409g of the overall weight. Next, we continued the experiment using that
amount of ibuprofen tablet until last titration where we can find how much of
exact ibuprofen it contains.
The amount of predicted ibuprofen and
the exact amount of ibuprofen got form the experiment is slightly different
where the predicted amount is 0.5g of ibuprofen while the amount got from
experiment is 0.48068g of ibuprofen. This is might be because of some mistakes
occurred during the experiment such as the residue is not titrated fully cause
lost of ibuprofen. Besides that, other possible mistake is the final titration
with sodium hydroxide is not stopped at the exact point which means the
titration was stopped before the end point. Therefore, it affects the amount of
ibuprofen that we got. Therefore, from the experiment we can calculate the percentage
of standard deviation which is 3.86%.
References
Aulton's Pharmaceutics The Design And Manufacture Of Medicines, Third Edition, 2007, Churchill Livingstone Elsevier, M. E. Aulton
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