Experiment 1: Evaluation of Effects Different Ingredients towards the Ointment Formulation

Title

Experiment 1: Evaluation of Effects Different Ingredients towards the Ointment Formulation

Objective

To determine the influence of ointment composition towards the physical properties of the ointment and the rate of drug release from the ointment formulation.

Introduction

            Ointment formulation is a form of semi-solid that suitable to be used as skin application. Ointment is a preparation that contains one or more active ingredient disperse homogenously. For ointment preparation, disperse phase is water, while continuous phase is oil, so it is a water-in-oil system. A good ointment should have an  interesting texture, easy to apply and able to release its drug content after application to targeted sites.

            In general for ointment preparation, drug or active ingredient is incorporated into oily medium of continuous phase. Ointment is normally applied topically to dry area of the skin for emollient effect. Ointment gives a protective layer to prevent dehydration of skin.

            Hence, the objective of this experiment is to determine the effect of different composition included on the physical properties of ointment and its preparation process, as well as the rate of release of active ingredient.

Apparatus

1.  Weighing machine

2. Weighing boat x 1

3. 100mL beaker x 1

4. Heater

5. Set of slap and spatula

6. Set of mortar and pestle

7. Dialysis bag (10cm) x 1

8. Short strings x 2

9. Glass rod

10. Water bath

11. Set of pipette (5cm) and pipette bulb

12. Cuvette plastic x 1

13. Ultraviolet spectrophotometer

Material

1. Emulsifying wax

2. White soft paraffin

3. Liquid paraffin

4. Acetylsalicylic acid

5. Distilled water

Method

1.      Emulsifying ointment (50g) is prepared by using following formula :

2. Small amount of ointment formed (5g) is took and put into a weighing boat and labelled. The ointment formed is compared its texture, clarity and colour.

3. Acetylsalicylic acid powder (1.5g) is incorporated into 10g of prepared ointment using levigation method. (Acetylsalicylic acid powder is crushed into finer using mortar and pestle if needed). The acetylsalicylic acid powder is inserted into dialysis bag. The both end of dialysis bag is made sure tighten properly with short strings, as shown in the figure below.

4. The bag is inserted into a 100mL beaker contained 50mL distilled water that has been heated to 37 degree Celsius. 

5. At the time interval of 5 minutes, 1 aliquot sample (3-4mL) of sample is pipetted and the release of acetylsalicylic acid from ointment base is determined using visible UV spectrometer. Distilled water is made sure stirred with a glass rod before sample is taken.

Discussion

1.      Comparison for the physical properties of different ointment formed and comments.

Ointment Physical appearence		I	II	III	IV
	1. Texture a) Spreadibility b) Greasiness c) Hardness	Very difficult A bit greasy Very hard	Difficult Less greasy Hard	Easy Greasy Soft	Very easy Very greasy Very soft
	2. Turbidity	Very turbid	Turbid	Less turbid	Less turbid
	3. Colour	White	White	White	White

In this experiment, the difference of the ointments made by different groups was the amount proportion of emulsifying wax and liquid paraffin used in the preparation. In this case, the amount of white soft paraffin used was same for every group.

            Based on the observation on the ointments formed from every group, comparison can be made based on the aspects of texture, clarity and the colour of the ointments. For the texture, ability to spread (spreadability), greasiness and hardness are taken into account for comparison. The spreadability and hardness of ointment was dependent on the amount of emulsifying wax used. Ointment I had the highest amount of emulsifying wax (21g), thus the ointment was the most difficult to spread and hardest compared to other 4 ointments. However, ointment IV was the softest and easiest to spread due to the least amount of emulsifying wax used (9g). In addition, ointment III was easier to spread and softer compared to ointment II as it contained less emulsifying wax. Apart from the contribution of emulsifying wax, liquid paraffin also will affect the hardness of ointment. The higher the content of liquid paraffin used, the softer the ointment formed.

Besides, the presence of liquid paraffin determines the greasiness of the ointment. The highest content of liquid paraffin (16g) in emulsifying ointment IV make it the greasiest ointment compared to ointments I, II and III. Ointment I was the least greasy due to the lowest amount of liquid paraffin used (4g).

For the comparison of turbidity, the physical appearance of emulsifying ointment I was the most turbid and the turbidity become less and less proceeding to the ointment IV due to the amount of liquid paraffin used. The higher the content of liquid paraffin used in the ointment, the lesser the degree of turbidity of ointment. For the appearance or colour of the ointment, all of the ointments formed were white in colour because liquid paraffin which is white gave its colour to the ointments.

2.      Plot the graph of UV absorption against time. Give explanation.

Time (min)	UV absorption
	0	5	10	15	20	25	30
UV absorption at 310nm	0.00	2.00	2.40	3.30	3.60	4.00	4.50

In this experiment, the dialysis bag resembled the human skin where the absorption of drug occurs when the drug crosses the membrane into the layers of the skin. The concentration of the drug in the distilled water detected by the UV spectrophotometer represents the amount of drug absorbed into the blood circulation and also the bioavailability of the drug.            

UV absorption represents the amount of drug that has crossed the membrane. The experiment showed that generally the UV absorption is proportional to the time throughout the experiment duration. By theory, UV absorption is proportional to the release time of acetylsalicylic acid from the tube. The gradient of the graph shows the rate of released of acetylsalicylic acid from the membrane.

The graph showed that in the beginning, the concentration of the acetylsalicylic acid in the distilled water increased slight rapidly with time from 0.00 to 5.00. The release rate will continue until a saturation point is achieved. As the time increased until a particular time, the releasing rate will reduce (gradient of the graph decreased). This situation can be explained from the graph as distilled water had achieved its saturation point. At the late stage of experiment, the releasing rate decreased gradually.

At the beginning of the experiment, the distilled water was kept at 37°C and it was hypotonic to the dialysis bag’s content consisted of acetylsalicylic acid. Thus, acetylsalicylic acid tended to diffuse out from the tube to the hypotonic solution (distilled water).

As the time increased, the concentration of salicylic acid in the distilled water increased. As the experiment proceeded, the concentration of the acetylsalicylic acid in the tube became isotonic with the distilled water in the surrounding. This showed that the equilibrium for diffusion of acetylsalicylic acid in and out of the tube was achieved. At this time, the gradient of the graph reduced.

The gradient did not show much difference compared from the starting till the end. When there was situation that gradient did not decrease or increase consistently maybe due to some errors such as careless attitude of experimenter didn’t make sure the cleanliness of apparatus. The concentration of acetylsalicylic acid may not be consistent if the distilled water in the beaker was not stirred uniformly. Besides, the technique of using spectrophotometry device also played a vital role in getting accurate results. The smooth surface of the cuvette should face the source of UV light and the smooth surface should be cleaned before it was placed into the device. Handprint when we held it caused the ultraviolet ray cannot pass through smoothly and affected the result. When we were holding the cuvette, it was not advisable to hold the smooth surface (where there is a triangle symbol on it).

1.      3. Plot a graph of UV absorption versus time for ointments that have different compositions. Compare and discuss the results.

Times(min)			UV absorption
			0	5	10	15	20	25	30
Emulsifying Ointment	I	1	0.064	0.081	0.097	0.095	0.106	0.115	0.121
		5	0.000	0.032	0.047	0.045	0.052	0.074	0.084
	II	2	0.004	0.007	0.011	0.028	0.032	0.037	0.049
		6	0.052	0.073	0.193	0.211	0.274	0.339	0.369
	III	3	0.104	0.111	0.119	0.155	0.162	0.191	0.221
		7	0.000	0.031	0.051	0.070	0.098	0.130	0.174
	IV	4	0.222	0.252	0.304	0.322	0.410	0.470	0.517
		8	0.019	0.089	0.115	0.162	0.190	0.204	0.275

Times(min)			UV absorption
			0	5	10	15	20	25	30
Emulsifying Ointment	I		0.032 ±0.045	0.057 ±0.035	0.072 ±0.035	0.070 ±0.035	0.079 ±0.038	0.095 ±0.029	0.103 ±0.026
	II		0.028 ±0.034	0.040 ±0.047	0.102 ±0.093	0.120 ±0.129	0.153 ±0.171	0.188 ±0.214	0.209 ±0.226
	III		0.052 ±0.074	0.071 ±0.057	0.085 ±0.048	0.113 ±0.060	0.130 ±0.045	0.161 ±0.043	0.198 ±0.043
	IV		0.121 ±0.144	0.171 ±0.115	0.210 ±0.134	0.242 ±0.113	0.300 ±0.156	0.337fc ±0.188	0.396 ±0.171

Table 1

From the graph, ointment IV showed the greatest gradient among the 4 slopes. This result that ointment IV had the highest reading of released acetylsalicylic acid. This was due to the presence of low amount of emulsifying wax and high proportion of liquid paraffin added that caused the matrix not fine enough to trap liquid paraffin and soft paraffin. Incomplete matrix caused the emulsifying ointment formed to be unstable and hence it cannot disperse evenly. As a result, this leaded to the hydrophilic ointment to diffuse into the distilled water through the membrane.

Meanwhile, from the graph drawn above, we can know that ointment I showed the lowest release rate of acetylsalicyclic acid. This was because ointment I is made up of formulation which contains high amount of emulsifying wax and low quantity of liquid paraffin. This formulation was much harder than the other formulations. The matrix formed was very solid and has less liquid. Hydrophilic aspirin may be able to disperse evenly in the ointment that was emulsified by the emulsifying agents (emulsifying wax) and the oil phase (liquid paraffin and soft paraffin) was not enough for the aspirin to diffuse through the membrane. Thus the concentration of aspirin in the distilled water was low. The uneven ratio caused it to be trapped in the ointment with the slow release rate.

There was inaccuracy of result from the graph where the gradient of for ointment III should be higher than ointment II. However, the gradient of both graphs were interchanged where ointment II is higher than ointment III. At the same time, the standard deviation calculated for from the average reading obtained had very high value for particular reading. This was because the result for 2 experiments conducted using same material proportion ended up in different reading which had large difference. The inaccuracy of the result of our experiment may be due to the inconsistency of stirring of the distilled water before taking the aliquot sample out at interval of 5 minutes. The inconsistency of stirring may result in the uneven distribution of the acetylsalicylic acid. As such, when the aliquot sample was taken, there may be uneven amount of acetylsalicylic acid being taken for UV spectrophotometer determination. Other errors include the loss of ointment when transferring the ointment into the dialysis bag.

As such, several precautions should be taken to reduce the errors made during the experiment. The distilled water should be stirred continuously in order to ensure the uniform distribution of acetylsalicylic acid. Besides, excess ointment should be made to overcome the loss of ointment while transferring it into the dialysis bag.

Question

1.      What is the function of each material used in the preparation of ointment? How did the usage of different amount content of Emulsifying Wax and Liquid Paraffin affect the physical characteristics of a ointment formulation as well as the rate of release of active ingredients from it?

Emulsifying wax is a emulsifying agent which has the function to decrease the interfacial surface tension so that drug particles can be distributed uniformly in the ointment preparation to prevent any sedimentation happens.

Liquid paraffin acts as a base. Liquid paraffin softens the ointments formed and decreases the ointment viscosity as well as for emollient function. Besides, white soft paraffin acts as ointment base. It increases the greasiness of ointment so that it can penetrate through the skin hydrophobic lipid bilayer more easily.

The different ratio and proportion of liquid paraffin and emulsifying wax has direct effect on the preparation. When the proportion of emulsifying wax decreases while liquid paraffin increases, the ability to spread and greasiness of ointment increases, meanwhile the hardness decreases. Hence, the drugs or active ingredients can be released from the formulation and pass through hydrophobic skin bilayer more readily.

Conclusion

Ointment composition can influence the physical properties of the ointment and the rate of drug release from it. Ointment which contains a lower amount of emulsifying wax and a higher amount of liquid paraffin is softer, less viscous and easy to be spread. Therefore, the rate of drug release also increases with the decrease in the amount of emulsifying wax and the increase in the amount of liquid paraffin used.

Reference

1. http://www.pharmlabs.unc.edu/labs/ointments/bases.htm

2. www.sciencedirect.com/science/.../S2211286313000055

3. www.drugs.com › Professionals › Medfacts

4. http://www.youtube.com/watch?v=b0rM5nxIUyQ

Pictures

Emulsifying wax was melted first on the evaporating dish due to its higher melting point. The evaporating dish was heated on the magnetic stirrer.

5g of the acetylsalicylic acid ointment was taken out and put into a weighing boat to observe the texture of the ointment formed.

The ointment was incorporated with acetylsalicylic acid powder and was levigated on a glass slab.

The cuvette containing the sample was then inserted into the UV spectrometer to determine the amount of acetylsalicylic acid released from the dialysis bag.

The reading shown on the UV and visible spectrometers measured the amount of ultraviolet and visible light transmitted or absorbed by the sample.

Questions in Practical 4

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

content ?

          The objective of the test for uniformity of diameter is to make sure the tablets produced are all uniform in size. This is important in the later process of tablet packaging either blister packaging or plastic container. The test for uniformity of content is to ensure that each tablet contains the similar amount of active ingredients and excipients so that each tablet contains correct dose of drugs. Hence, the bioavailability and efficacy carried out by the drug is the same for each of the tablet taken orally.

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

          For uniformity of diameter, all tablets are applicable such as coated tablet, effervescence tablet and modified release tablet except enteric tablet, film-coated tablet and sugar-coated tablet. In this case, mostly capsules are applicable such as hard capsules, soft capsules, gastro-resistant capsules, modified-release capsules and cachets.

           For uniformity of content, normally single dose preparations are required. Tablets and capsules included are coated tablets, others than film-coated tablets containing 50mg or more of an active ingredient that comprises 50% or more of one tablet. Tablets or capsules have active ingredients less than 5% are needed. Liquid-filled soft capsules, solids packaged in single-unit containers with or without added substances and solutions for inhalation packaged in glass or plastic ampules are not applicable for testing uniformity of content.

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

The reasons for the non-compliance to test for uniformity of weight are due to uneven feeding of granules into the die due to irregular movement of the lower punch that cause variation in capacity die space. This will result in unsatisfactory mix of ingredients at blending stage, and amount of ingredients cannot be weighed accurately. Segregation of  compound in formulation is also can happen.

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

           Dissolution test suitable to be used for batch to batch quality control because it is easier to assess batch-to-batch consistency of solid oral dosage forms such as tablets which can be easily obtained and to predict in vivo drug release profiles. It also allows the prediction of time for complete release of the drug. This test is very effective and guarantee the quality of the pharmaceutical products by detecting deviations in manufacturing in order maintain to consistency and ensure optimum bioavailability so that the tablets can give the desired therapeutic effect.

5. Explain the difference found in the procedure for dissolution test in United States Pharmacopoeia and the British Pharmacopoeia.

            In Unites States Pharmacopoeia, typical acceptance criteria for the amount of active ingredient dissolved must be in the range of 75% to 80% whereas, in British Pharmacopoeia, the amount of active ingredient dissolved must not be less than 70%. In United States Pharmacopoeia, a retest may be carried out in three stages with different amount of tablets if the test failed. In British Pharmacopoeia, if the test failed, a retest may be carried out using the same number of units of tablets.

Practical 4 - Content of Ibuprofen (assay)

Introduction:

Ibuprofen is a non-steroidal anti-inflammatory drug (NSAID). It helps to reduce hormones that can cause inflammation and pain in the body. It is mostly used to treat pain and inflammation caused by many conditions such as headache, toothache and back pain. Ibuprofen also used to reduce fever.

Ibuprofen tablets are available in different strengths range from 200 mg to 800 mg.

Objective:

1.       To determine the given formulation of Ibuprofen.

Apparatus and materials:

1.       Conical flask

2.       Measuring cylinder

3.       Measuring balance

4.       Filter funnel

5.       Filter paper

6.       Hairdryer

7.       Retort stand

8.       Burette

9.       Pestle and mortar

10.   20 Ibuprofen tablets with strength of 400 mg.

11.    Chloroform

12.   Ethanol

13.   Phenolphthalein solution

14.   0.1M sodium hydroxide solution

Procedure:

1.       20 Ibuprofen tablets with 400 mg strength are selected at random and weighed. The total weight is measured. The tablets are then powdered.

2.       0.6467 g of the powder containing 0.5 g Ibuprofen is extracted with 20 ml chloroform for 15 minutes in fume hood. Then, it is filtered through a sintered glass crucible.

3.       The residue is washed with 3 x 10 ml chloroform and filtered again. The combined filtrate is gently evaporated using a hairdryer just to dryness in a current of air. The residue is dissolved in 100 ml 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 until the solution turns pink in colour. The content of ibuprofen is calculated is each ml of 0.1M sodium hydroxide is equivalent to 0.02063 g of C₁₃H₁₈O₂.

Results:

Total weight = 10.3475 g

Content of ibuprofen in 20 tablets = 0.4 g x 20

                                                                    = 8 g

10.3475 g of total weight contains 8 g of ibuprofen.

So, 0.6467 g from the total weight contains 0.5 g of ibuprofen.

Initial reading of burette = 0.00 ml of 0.1M sodium hydroxide

Final reading of burette = 22.3 ml 0.1M sodium hydroxide

1 ml of 0.1M sodium hydroxide is equivalent to 0.02063 g of C₁₃H₁₈O₂

So, 22.3 ml x 0.02063 g = 0.46 g Ibuprofen is present

Percentage error = (0.46 g – 0.5 g) / 0.5 g x 100 % = -8 %

                                                                                  = 8 %

Discussion:

In this experiment, the final result which is 0.46 g of Ibuprofen is obtained. It is slightly different compared to the actual weight which is 0.5 g. 8 % of percentage error determines that during the experiment, there are some errors involved. It includes uneven crushing of tablets resulting in not uniform powder and reduces powder flow thus not easy to dissolve. Second error is parallax error when measuring the chloroform. Eyes are not perpendicular to the measure and causing inaccurate measurement.  Error also occurred during the extraction process when the solution is not placed in fume hood causing it to evaporate. This will affect the content of ibuprofen present in the solution

Conclusion:

In conclusion, the weight of ibuprofen obtained is 0.46 g and the percentage error is 8 %. Thus, this test is suitable to determine the accurate near value of ibuprofen content but has to comply with some conditions to avoid error and to obtain good result. 

References:

1. http://web1.caryacademy.org/facultywebs/gray_rushin/StudentProjects/CompoundWebSites/1998/Ibuprofen/structibu.htm [structure of Ibuprofen]

2. BNF-65 Ed, BNF publications. (pg 671)

Practical 4 - Dosage performance tests (Dissolution)

Objective:

To investigate the percentage amount of ibuprofen dissolved

Introduction:

The dissolution test for tablet is done to ensure that the tablet dissolution rate is at the optimum and the desired value. Besides that, tablet dissolution test allows us to determine the bioavailability of the active ingredient of the drug in tablet form in the body to give the desired pharmacological effects effectively. We can also determine the specific pH value at which the tablet dissolves best. If the dissolution of the tablet is not at its optimum level as predicted, then, we will have to reformulate or find out what errors have been made during the pre-formulation procedure of the tablet.

Procedure:

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

2. The temperature of the dissolution medium was kept in check to ensure the temperature was at 37 ± 0.5°C.

3. One Ibuprofen tablet was placed into each dry basket assembly.

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

5. 10mL samples of the dissolution medium from each vessel were withdrawn for analysis after 30 minutes and the solution was filtered using suitable filter. Sampling was done from middle point between the surface of the dissolution medium and the top of rotating basket, and not less than 10mm from 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 10mg of ibuprofen reference standard to 50ml with dissolution medium.

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

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

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

At/As    X     W/50     X     2/25    X     P    X     900    X    25/2    X    100/200

Where,

At = absorbance of sample solution

As = 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:

At = 0.859

As = 3.847

Percentage amount of ibuprofen dissolved:

At/As    X     W/50     X     2/25    X     P    X     900    X    25/2    X    100/200

0.859/3.847   X     10/50     X     2/25    X     98/100    X     900    X    25/2    X    100/200 = 19.69%

Discussion:

            From the calculated value, the percentage amount of ibuprofen dissolved is 19.69% . The tablet does not comply with the requirements of United States of Pharmacopoeia as the percentage is less than 75%. This indicates that there are errors made during conducting this experiment.

            One of the main errors is the expiry date of the sample of ibuprofen tablet. The ibuprofen sample may have expired and this has reduced the quality of the tablet. The ingredients must have become unstable and did not dissolve properly. Thus, this may have greatly affected and resulted in the above poor dissolution rate and absorption of wavelength during the measurement using the spectrophotometer.

Besides, the stirring speed may not have reached 150 rpm. This will cause the dissolution rate to be slow and the low speed could have affected the dissolution rate. Moreover, the temperature of the dissolution vessel might be one of the factors. We did not monitor the temperature which must be maintained at 37°C with ± 0.5°C. Low temperature may cause poor dissolution while high temperature may alter the composition of the ibuprofen tablet.

Furthermore, the presence of dissolved gas in the dissolution medium or buffer solution might lead to inaccuracy of results by slowing down the dissolution rate. 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.

            Therefore certain precautions must be taken to ensure the accuracy of the results. First, the sample must be in good condition and the expiry date of the tablet should be checked before use. We also must make sure the dissolution vessel is calibrated before used so that we can obtain accurate results. Besides, we must always double check the setting of temperature, stirring speed and time required for stirring process to avoid unnecessary errors. To prevent the presence of dissolved gas in the dissolution medium or buffer solution, it is advisable to put the solution in ultrasonic water bath.

Conclusion:

The percentage amount of ibuprofen dissolved is 19.69%. This value is less than 75%, therefore the tablet does not comply with the requirements of United States Pharmacopoeia.

References:
1. http://www.pharmainfo.net/Dissolution/dissolution-testing-various-dosage-forms
2. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3160163/

Practical 4 - Dosage Performance Tests (Disintegration)

Objective: 

The objectives for disintegration test is to determine how long the time taken needed to tablet for disintegrate and whether it is disintegrate properly when placed in a liquid medium under the experimental condition in this experiment

Introduction:

Disintegration testing determines whether tablets or capsules disintegrate within a defined period of time when placed in a liquid medium .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 gelatine is not of pharmacopoeial quality.

Apparatus and Materials:

Tablets , Copley Disintegration Tester, Thermometer and Distilled Water,500 mL distilled water, 500 mL beaker, disintegration machine (include disc, mechanical device to control up-down movement (28-32 cpm), device to control temperature (37 °C))

Procedure:

1. The disintegration test equipment was set up by following the instruction in the manual of                    operation.

2. 500 mL of distilled water was added into the beaker and then added to the disintegration  machine.     Then, the water was left until the temperature of water is about 37°C .

3. The time was set up to 60 minutes. Three tablet of the same types was added into each tube with         another 3 tablet from another group. Then, the disk was added into each tube before started the           operation.

4. The tablet in each tube was checked whether it is pass the test or not at the end of the operation.

5. The tablets pass the test if all 3 tablets disintegrate within 60 minutes. If there is any tablet that           does not disintegrate, we must pressed the tablet and if the tablet was disintegrate when we press, it     also means that the tablet comply with the test

Results:

Tablets	Dissolving rate	Type of tablets
Mefenamic Acid	Fully dissolve	Uncoated tablets
Methyldopa	Fully dissolve	Uncoated tablets
Methyldopa	Fully dissolve	Uncoated tablets
Ibuprofen	Fully dissolve	Uncoated tablets
Uphamol	Fully dissolve	Uncoated tablets
Erythromycin	Fully dissolve but leaving a thin sheets	Enteric coated tablets
Erythromycin	Fully dissolve but leaving a thin sheets	Enteric coated tablets
Cephalin	Fully dissolve	Uncoated tablets

Discussion:

The drug must first disintegrate into smaller particles before a tablet/hard gelatin capsule can dissolve and hence allow the active drug to be absorbed into the body,

During testing, the basket assembly is raised and lowered in simulated gastric fluid at 37 degrees C 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.

The error during disintegration test experiment is the water in the beaker may not heat up adequately. So, these may affect the disintegration process. Then, the tablet was expired. So, it may affect the disintegration rate.

Conclusion:

All of the tablets passed the disintegration test as it disintegrates completely in less than the specified time which is 1 hour. The experiment is  a success.

References:

1.       http://www.pharmainfo.net/disintegration-test