Tuesday, 24 December 2013

practical 6: Experiment 5 Content of ibuprofen (assay)

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

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.


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

= 1.0409g of total amount   = 0.5g of ibuprofen
From experiment,
= 1.0409g of total amount   = 0.48068g of ibuprofen
Percentage of standard deviation is [100 – (0.48068g of ibuprofen / 0.5g of ibuprofen x 100)] = 3. 86%


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%.

Aulton's Pharmaceutics The Design And Manufacture Of Medicines, Third Edition, 2007, Churchill Livingstone Elsevier, M. E. Aulton

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