TABLET AND CAPSULES (Experiment 5)

Experiment 5: Content of Ibuprofen

Objective

To determine the percentage of content of Ibuprofen in tablet

Introduction

A tablet is a pharmaceutical dosage form. It comprises a mixture of active substances and excipients, usually in powder form, pressed or compacted from a powder into a solid dose. The excipients can include diluents, binders or granulating agents, glidants (flow aids) and lubricants to ensure efficient tableting; disintegrants to promote tablet break-up in the digestive tract; sweeteners or flavours to enhance taste; and pigments to make the tablets visually attractive. A polymer coating is often applied to make the tablet smoother and easier to swallow, to control the release rate of the active ingredient, to make it more resistant to the environment (extending its shelf life), or to enhance the tablet's appearance. In this experiment, ibuprofen tablet 200mg is used to test its content of active ingredient. Variation between tablet with respect to dose and weight must be reduced to a minimum.Uniformity of weight is an in process test parameter which ensures consistency of dosage units during compression. Limits for this variation are defined as standards in pharmacopoeias.

Apparatus

Mortar and pestle, 100 ml measuring cylinder., 250 ml conical flask, filter paper, filter funnel, weighing machine, burette, hair dryer, weighing boat, separating funnel and 100 ml beaker

Chemicals

200 mg Ibuprofen tablets, chloroform, ethanol (96%), phenolphthalein solution, 0.1M sodium hydroxide

Procedures

1.          20 Ibuprofen tablets were previously selected at random and were weighed by using weighing machine. The reading was recorded.

2.          The tablets were triturated by using mortar and pestle to form powder.

3.          A quantity of powder containing 0.5g Ibuprofen was extracted with 20ml of chloroform by using separating funnel in the fume cupboard for 15 minutes.

4.          Then, the extract was filtered through a filter paper. The residue was washed with 10ml chloroform. The combined filtrated was then gently evaporated to dryness in a current of air by using hair dryer.

5.          The residue was then dissolved in 100ml ethanol (96%) previously neutralized to phenolphthalein solution in a 250ml conical flask.

6.          The solution then titrated with 0.1M sodium hydroxide to reach the end point with phenolphthalein solution as the indicator by using burette.

7.          The content of Ibuprofen was then calculated if each ml of 0.1M sodium hydroxide is equivalent to 0.02063g of C13H18O2.

Results and Calculations

Total weight for 20 Ibuprofen tablets = 8.2509 g

Average weight for 1 Ibuprofen tablet = 8.2509 g

                                                                   20

                                                           

                                                             = 0.4125g

Volume of 0.1M sodium hydroxide required = 27.30ml

1 ml of 0.1M sodium hydroxide is equivalent to 0.02063g of Ibuprofen.

 So, content of Ibuprofen extracted = 27.30 × 0.02063

                                                         = 0.5631g

                                                         = 563.1 mg

Percentage of content of Ibuprofen in the sample given

=    Ibuprofen extracted           ×   100%

      Quantity of Ibuprofen      

=   563.1 mg     ×   100%

     500.0 mg              

= 112.62%

Discussion

The aim of the experiment is to determine the content of Ibuprofen in tablet. Based on the standards in British Pharmacopoeia (B.P), tablets should have 85%-115% of Ibuprofen as active ingredient. Any value outside the range is considered fail in the B.P test for content of active ingredient. From the results we obtained, the samples given were containing 112.62% of Ibuprofen. This value is within the range of the standards in the British Pharmacopoeia (B.P). However, there are still some errors which cause the results not 100% accurately.

The first error that occurs was parallax error. Student did not read the readings of burette parallel to the scale and this caused error in the results. Therefore students should place the eye sight parallel to the level of meniscus and repeat the titration if necessary to get more accurate results. Futhermore, the ibuprofen tablets used were expired. This will result inaccuracy of experiment too. Tablets used in experiment should be in well condition so that we can obtain accurate results. Lastly, we did not notice the changes of colour of the solution with indicator carefully. This caused excess amount of NaOH added into the conical flask. As a result, the content of extracted ibuprofen was exceeded than we estimated. We should place a white tile below the conical flask so that we can discover the changes of colour easier.

Conclusion

            The content weight of Ibuprofen extracted is 563.1mg.  The tablets that we tested were within the range of standards of British Pharmacopoeia.

Questions:

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

The tests for uniformity of diameter is conducted to determine the thickness of the tablet as well so that progress of packaging can be facilitated. It is also important for demonstrating adequate quality control and for ensuring the optimal performance of the final product. For the uniformity of content test, it can ensure the tablet contains the desired amount of drug substance intended with little variation among tablets within a batch so that the tablet will include the correct dose of drug.

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

All types of tablet must be tested for uniformity of diameter. These include uncoated and coated tablets except enteric coated tablets, film-coated tablets and sugar-coated tablets. Capsule is not suitable to be tested using uniformity of diameter test. Tablets which are uncoated and compression-coated must be tested for uniformity of content whereas hard and soft gelatin capsule must also undergo the same uniformity of content test.

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

During manufacturing and handling, tablets are subjected to stresses from collision and tablet sliding towards one another and other solid surfaces, which can result in the removal of small fragments and particles from the tablet surface. The result will be progressive reduction in weight and change in appearance.

4. Why does dissolution test suitable to be used for batch to batch quality control?
This is because samples to be used in the test can be easily obtained without experiencing any changes in the dissolved drug concentration. Furthermore, the quality of the pharmaceutical products can be ensured so that the consistency and bioequivalence testing aspects can be proven.

5. Explain the difference found in the procedure for dissolution test in the United States Pharmacopoeia (USP) and the British Pharmacopoeia (BP).
USP used rotating-basket method and paddle method while BP used flow through cell method and also the methods in USP. USP determines compliance in the dissolution requirements where stated in the individual monograph for a tablet or a capsule dosage form whereas BP determines the dissolution rate of active ingredient of solid dosage forms. The speed used in USP is 25-150rmp ± 4% while the speed used in BP is 25-150rmp ± 5%. Lastly, USP consists of 3 stages, S₁, S₂ and S₃ while in BP, if one fails the requirement, a further numbers of tablets may be tested individually and all must comply. No retesting is permitted.

Reference
1.http://en.wikipedia.org/wiki/Tablet_(pharmacy)
2.http://pharmacy.about.com/od/Glossary/g/What-Are-Active-Pharmaceutical-Ingredients-Or-Apis.htm