EXPERIMENT 5 : CONTENT OF IBUPROFEN (ASSAY)

Title 

Content of ibuprofen (assay)

Objective 

To calculate the content of ibuprofen

Apparatus 

Filter funnel , Filter paper , Beaker , Retort stand , Conical flask , Dryer , Burette , Weighing boat

Materials 

20 tablet of ibuprofen

Ethanol

Phenophthalein

0.1M sodium hydroxide

Procedure :

1.      20 Ibuprofen tablets previously selected at random is weighed and powdered.

2.      A quantity of powder containing 0.5 g ibuprofen is extracted with 20 ml chloroform for 15 minutes and is filtered through a sintered glass crucible ( BS Porosity No. 1)

3.      The residue is washed 3 times with 10ml 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 0.02063g of C₁₃H₁₈O_2.

Result and calculation

The weight of 20 tablets Ibuprofen in powder form                          = 7.94g

Active ingredient of ibuprofen in each tablet                                    = 0.5g

Active ingredient of ibuprofen in 20 tablets                                     = 4.0 g

500 mg / 4000 mg  = Y / 7940 mg

Y = 992.5 mg

Titration of 0.1M sodium hydroxide = 15 ml

0.1M sodium hydroxide is equal to 0.02063 g of Ibuprofen

15 ml x 0.02063 g = 0.30945 g

Percentage of deviation : [ (0.5 – 0.30945) x 100 ] ÷ 0.5 = 38.11 %

Discussion

            The amount of active ingredient in each Ibuprofen tablet is 0.5g which is expected  to be the final mass. However, the calculated value is different from theoretical value which is 38.11 % deviation ( 0.30945 g). The volume of NaOh of titration process is expected to be aroun 24 mL for 0.5 g of Ibuprofen.

            This may be due to some errors occurred during the experiment.The solution are not filtered properly using filter funnel and filter paper which then cause some of the powder that are not dissolved in the chloroform will pass through into the conical flask. In addition to that, the tablets used might be already expired.  So, the physicochemical properties of Ibuprofen tablets might be affected.

Conclusion

            In conclusion, the content of Ibuprofen from the experiment is 0.30945 g which is slightly different with theory, 0.5 g due to some errors.

References

1.         https://en.wikipedia.org/wiki/Ibuprofen

2.         Introduction to Pharmaceutical Analysis, By Steen Hansen, Stig Pedersen-Bjergaard, Knut Rasmussen

(https://books.google.com.my/books?id=S7S6a4OYTasC&lpg=PP1&pg=PP1#v=onepage&q&f=false )

Questions

1. What are the objectives of the tests for uniformity of diameter and uniformity of content ?

To ensure each tablet contain the amount of drug substance intended with little variation among tablets within a batch. Then, to indicate the individual contents are within limits set with reference to the average content of the sample. Tablet diameter is a vital quality control test for tablet packaging which affects packaging. Tablet thickness is determined by the diameter of the tablet.

2. State the types of tablets and capsules that must be tested for for uniformity of diameter and uniformity of content.

•           Effervescent Tablet

•           Hard and soft capsule

•           Modified Release Tablet/capsule

•           Enteric-coated tablet/capsule

•           Uncoated tablet

3. Give reasons for the non-compliance to test for uniformity of weight.

It is because of the uneven feeding of granules into the die. In other words, non-uniformity movement of the lower punch will result in the variation in capacity of die space and have to carry out the test. If the ingredients do not mix well at blending stage or do not weight the amount of ingredients accurately, this will also produce those non-compliance.

4.Why does dissolution test suitable to be used for batch to batch quality control?

 It is as an important part of product development and to obtain information on test batches used in bioavailability/bioequivalence studies and pivotal clinical studies to support specifications for quality control.

5.Describe other apparatus that you can use to conduct dissolution test apart from the one found in the laboratory.

In United States Pharmacopeia (USP) General Chapter <711> Dissolution, there are four dissolution apparatuses standardized and specified.They are:

• USP Dissolution Apparatus 1 - Basket (37°C)

• USP Dissolution Apparatus 2 - Paddle (37°C)

• USP Dissolution Apparatus 3 - Reciprocating Cylinder (37°C)

• USP Dissolution Apparatus 4 - Flow-Through Cell (37°C)

USP Dissolution Apparatus 2 is the most widely used apparatus among these four.

The performances of dissolution apparatuses are highly dependent on hydrodynamics due to the nature of dissolution testing. The designs of the dissolution apparatuses and the ways of operating dissolution apparatuses have huge impacts on the hydrodynamics, thus the performances. Hydrodynamic studies in dissolution apparatuses were carried out by researchers over the past few years with both experimental methods and numerical modeling such as Computational Fluid Dynamics(CFD).