EXPERIMENT 2.4 : DOSAGE PERFORMANCE TESTS

PART I

TITLE: Disintegration test for sugar-coated tablet

AIM   : To investigate the compliance of tablets with the disintegration test.

INTRODUCTION:

Tablet disintegration testing is used as a quality-assurance measure. This is because, for some cases if the disintegration time is too high; it means that the tablet is too highly compressed or the capsule shell gelatin is not of pharmacopoeia quality. Also if the disintegration time is not uniform in a set of samples being analyzed, it indicates batch inconsistency and lack of batch uniformity. It is not a true predictor of how well the dosage form will release its active ingredient in vivo.

APPARATUS & MATERIALS:

                                                                 

                                                                   TabletsCopley 

                                                             Disintegration Tester

PROCEDURE:

1. The apparatus for the disintegration test is set up according to its operation manual.

2. The temperature of the disintegration medium (water) is ensured at 37 ± 2⁰C.

3. The time is set to 60 minutes. One tablet is introduced into each tube, the disk is added into each tube and operation started.

4. The tablet in each tube is checked at the end of the operation.

5. Tablets comply with the test if all tablets disintegrate in 60 minutes. If not, test is repeated using 6 new tablets but replacing the disintegration medium (water) with 0.1M hydrochloric acid. Tablets comply with the test if all 6 tablets disintegrate in the acidic medium.

RESULTS: Uphamol Cold & Flu Tablet which is used completely disintegrate after 60 minutes.

DISCUSSION:

It has long been recognized that before a tablet/hard gelatin capsule can dissolve and hence allow the active drug to be absorbed into the body, it must first disintegrate into smaller particles.

During testing, the basket assembly is raised and lowered in simulated gastric fluid at 37 ± 2⁰C whilst the tablet is continually “hammered” by a plastic disk of defined proportions to simulate in vivo conditions. The tablet is said to pass the test providing that no tablet residue remains on the mesh after the designated test period.

But as mentioned earlier, this test is not a true predictor of how well the dosage form will release its active ingredient in vivo. This is because of some limitations it cannot follow. Firstly, it does not mimic conditions of gastrointestinal tract such as the muscle movement. Thus there’s no guarantee of clinical efficacy. Secondly, this test is controlled by experimental variables.

CONCLUSION:

Tablet used passed the disintegration test as it disintegrates completely in the specified time which is 1 hour.

PART II

TITLE: Dissolution test for tablet

AIM   : To investigate the percentage amount of ibuprofen dissolved.

INTRODUCTION:

The dissolution test for tablet is necessary to perform as to ensure the desired tablet dissolution rate. If it is not what we predicted, we will have to reformulate or find out what went wrong during the preformulation of tablets. Besides, it allows us to predict the bioavailability and the expected pharmacologic effect of the drug when administered into the body. Besides, pH of the drug where it has optimum dissolution rate is also determined.

PROCEDURE:

1. The dissolution vessels are filled up with buffered solution to 900 mL mark. The temperature was set to 37 °C.

2. The temperature of the dissolution medium was checked to ensure that it is ± 0.5 °C.

3. One 200mg Ibuprofen Tablet was put into each of the dry basket.

4. The stirring speed was set to 150 rpm. Then, the baskets was lower assembly into the position in the vessel and the operation was started.

5. After 30 minutes, 10 ml of the samples of the dissolution medium from each of the vessel was withdrawn for analysis and the solution was filtered using a syringe filter. Sampling should be done from middle point between the surface of the dissolution medium and the top of rotating basket, and not less than 10 mm form the wall of the vessel. The volume of aliquot withdrawn for analysis was replaced with the same volume of same dissolution medium.

6.  A standard solution of ibuprofen was prepared by diluting 10.0 mg of ibuprofen reference to 50 ml with dissolution medium.

7. Each of 2.0 ml of sample solution and 2.0 ml of standard solution were diluted to 25 ml with dissolution medium in separate volumetric flasks.

8. The absorption of both solutions were measured in a 1 cm cell at a wavelength of 221 nm.

9. The percentage of amount of ibuprofen dissolved was calculated by using the following formula:

A_t/A_s    X     W/50     X     2/25    X     P    X     900    X    25/2    X    100/200

 Where

A_t = absorbance of sample solution

A_s = absorbance of standard solution

W = weight of ibuprofen reference standard used.

P   = purity of ibuprofen reference standard

10. From the result obtained, the tablet compliance with the requirements of the United States Pharmacopoeia was determined.

USP limits : Not less than 75% of the stated amount of ibuprofen dissolved in 30 minutes.

RESULTS:

A_t = 0.987

A_s = 3.913

Percentage of amount of amount of ibuprofen dissolved = 22.24%

Percentage error = (75 – 22.24)/75 X 100% = 70.35%

DISCUSSION:

The percentage error is 70.35% and this value does not comply to USP limit. Some errors have made during the experiment.

One of the errors is the quality and expiry date of the sample of ibuprofen. The ibuprofen sampled may have expired and this may greatly affected the poor dissolution and absorption of wavelength during spectrophotometer.

Besides, the temperature of the dissolution vessel is one of the factors. If the temperature of the solution is not maintained at 37 degree Celsius with ± 0.5 degree Celsius, this will affect the dissolution rate of the drug. Low temperature may cause poor dissolution while high temperature may alter the composition of the ibuprofen tablet.

Moreover, the stirring speed may not reached or set at 150 rpm. The lower the stirring speed, the lower the dissolution rate, thus result with error is manifested. Besides, the time for stirring may not set at 30 minutes or it was set less than that. This will significantly cause errors.

Furthermore, the presence of dissolved gas in the dissolution medium or buffered solution might lead to inaccuracy of results. The dissolution rate will be slowed.

The syringe filter used may absorb some of the sample during withdrawing of sample. This will reduces the percentage of dissolved ibuprofen for analysis. Thus, less ibuprofen sample was detected.

PRECAUTION :

1. We must use a good tablet that is not expired.

2. We must make sure the dissolution vessel is calibrated before used so that we can obtain accurate results.

3. Besides, we must always double check on the setting of temperature, stirring speed and time of stirring.

4. We must also make sure the syringe filter is cleaned and non-absorbent type to ensure that the sample is not absorbed onto it.

CONCLUSIONS:

The A_t = 0.987, A_s = 3.913 and the percentage of amount of ibuprofen dissolved is 22.24%

REFERENCES:

http://pharmatreasures.blogspot.com/2012/02/what-is-difference-between-dissolution.html

http://www.pharmainfo.net/tablet-evaluation-tests/dissolution

http://www.medscape.com/viewarticle/466062_2