QUALITY CONTROL TESTS FOR TABLETS - EXPERIMENT

EXPT NO: 05                                                                                                            DATE:

QUALITY CONTROL TESTS FOR TABLETS

AIM: To carry out the various quality control tests for tablets.

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EVALUATION:

Once the tablet is designed it’s product quality, quantitative evaluation and assessment of tablets chemical, physical & bioavailability must be done. Not only could all three properly classes have a significant stability profile but the stability profile may be inter related i.e. chemical breakdown or interaction between tablet composition may alter physical properties, greatly changing bioavailability of tablet.

1. GENERAL APPEARANCE

It is essential for consumer acceptance. Control of lot-to-lot and tablet-to-tablet uniformity For monitoring trouble-free manufacturing it involves measurements of - Tablet’s size & shape, colour, presence or absence of odour, taste, surface texture, physical flow, and consistency and any identifying marking.

a. Size and shape

The size and shape of tablet can be dimensionally described and can be determined by tooling during compression. The thickness of tablet is only dimensional variable. At constant pressure compressive load.

Tablet thickness varies with change in die fill, particle size distribution and packing of particle. While with constant die fill thickness varies with variation in compressive load.

Tablet thickness should be controlled within ±5% variation of a standard value. It should be maintained to facilitate packing.

b. Unique identification marking

Pharmaceutical companies manufacturing tablets often use some type of unique marking on the tablet for identification of their product. The marking utilize same from of embossing, engraving or printing of company name, symbol or product code. Which are sole means of identification of tablet.

c. Organoleptic properties

Colour

Many pharmaceutical tab use colour as means of identification, to evaluate colour reflectance spectophotometry, colorimetry and photometer is used.

Odour

Presence of odour in batch of tablets indicates a stability problem.

E.g. Odour of acetic acid in degrading aspiring tablet.

Taste

It is important for consumer acceptance of chewable tablet

2. HARDNESS AND FRIABILITY

Tablet requires certain amount of strength, hardness and resistance to friability to withstand mechanical shock of handling in manufacturing packaging and shipping. Tablet hardness is defined as the force required to break a tablet in diametric compression test. Hardness is thus termed as tablet crushing strength.

Tablet hardness is determined by Monsanto tester, strong-cobb tester Pfizer tester etc.
Monsanto tester consists of a barrel containing a compressible spring held between two
plungers. The lower plunger is placed in contact with the tablet and zero reading is taken.
The upper plunger is then forced the tablet fractures. Std limit 3-6 kg/cm3

3. FRIABILITY TEST

Tablet hardness is not an absolute indicator of strength since some formulations when compressed into very hard tablet tend to cap on attrition losing their crown portion: another measure of tab strength it’s friability is measured. It is measured using friabilator known as roche friabilator. Tablets are subjected to friabilator thus tablets are subjected to combined effect of abrasion and shake by utilizing a plastic chamber that involves at 25 rpm dropping the tablet at a distance 6 inches with each revolution. Standard limit for weight loss is 0.5 — 0.1 %

Procedure:

Weigh 10 tablets initially and place them in a friabilator that is then operated for 100 revolutions. The tablets are then re-weighed. Conventional compressed tablets that lose less than 0.5 -1 % of their weight are acceptable.

4. DRUG CONTENT AND RELEASE

A physically sound tablet may not produce desire effect. To evaluate tablet’s potential for efficacy the amount of drug per tablet need to be mentioned

a. Weight variation. V

With a tablet designed to contain a special; amount of drug in a special amount of tablet formula, the weight of tablet being made is routinely measured to help ensure that a Tablet contains the proper amount of drug in practice composite sample of tablet 10 or 20 are taken and weighed throughout the compressions process. The composite weight divided by 10 or 20 however provide an average weight but contain the usual problems of average value within the composite sample that has an acceptable average weight there could be tablet excessively over weight or underweight.

The weight variation test would be satisfactory method of determining the drug content, uniformity of tablet if the tablet were all or essentially 90-95% active ingredient. Not more than2 tablet shows deviation twice the limit

Average weight of tablet (mg)	Maximum permissible limit for deviation
Tablet of 80 mg or less	± 10.00%
More than 80 less than 250mg	± 7.5%
250mg or more	± 5.0%

Procedure

Weigh about 20 tablets and weigh them individually. Calculate the average weight by:

Weight of each tablet                                          W₁

Average wt of each tablet                                   W_asg

Deviation from average weight                            W₁ - W_avg

% of deviation                                                    W₁ W_avg / W_avg X 100

Compare the % of deviation with standard limits.

b. Disintegration test

Generally expected is that for a drug to be readily available it must be in solution. The important step towards solution is break down of tablet into smaller particles all granules is called as disintegration to measure the disintegration tester is used it consist of six glass tube that are there inches long open at the top and held against ten means screen at the bottom end of the basket the rack assembly. To test for the disintegration time one tablets is placed in each tube and basket track is placed in a one liter beaker of water stimulates gastric fluid or stimulated intestinal fluid at 37+_ 2 degree C. Such that the tablets remain 2.5cm below the surface of the liquid on their upward movement and descend not closer than 2.5cm from the bottom. The assembly is moved up and down through a distance of 5 to 6 cm at frequency of 28 to 30 rpm. The tablet must disintegrate and au particles must pass through 10-mesh screen. Uncoated tablet have a disintegration time standard as low as 5 minute coated tablet have disintegration time 30 minute and enteric coated tablet show no evidence of disintegration after one hour in gastric fluid and same tablet ar3 tested in intestinal fluid and should disintegrate in two hour.

c. Dissolution test.

As the rate limiting step in drug absorption and there are by its availability is dissolution of drug, its necessary for a drugs to get dissolve in G.l.T The original rationale for using tablet disintegration test was the fact that tablet disintegrated into small particle enhance dissolution. But, its offer no assurance that disintegration particle will dissolve in at an appropriate rate thus pharmacopoeia prescribe that dissolution test for determine at availability of the drug. Thus the two objectives in development of in vitro dissolution test.

1.       Release of drug from the tablet is as possible to 100%

2.       Rate of drug release is uniform batch to batch and is same as the release rate from those batches proven to be to bioavailability and clinically effective.

To determine dissolution rate dissolution apparatus are used. Which are of two types

Apparatus-I (basket type)

A single tablet is placed in small wire mesh basket fastened to the bottom of the shaft connected to variable speed mortar. The basket is immersed in dissolution medium contained in 100ml flask. The flask is maintained at 37 ± 0.5°c. The motor is adjusted to turn at specified speed and sample of fluid are with drown at interval to determine the amount of the drug in solution.

Apparatus -2(paddle type)

The same equipment as in apparatus 1 is used except that a peddle replaces their basket.

Dissolution testing and enter precaution is turned in3 stage. If the results do not conform to the requirements at stage S1, continue testing with additional tablets through stages S2 and S3 unless the result conform at stage S2.

Acceptance table

Stage	Number Tested	Acceptance Criteria
S1	6	Each unit not less than D*+5%
S2	6	Average of 12 units (S1+S2) is equal to or greater than D and no unit is less than D-15%
S3	12	Average of 24 units (S1+S2+S3) is equal to or greater than D, not more than 2 units are less than D-15% and no unit is less than D-125%

·         D is the amount of dissolved active iriredient specified in the individual monograph.

PROCEDURE

900 ml of phosphate buffer (ph=7.8) is introduced in the vessel and placed in dissolution apparatus. And temp is maintained at 37 ± 0.5°C the paddle is fixed at ht of 2-5 cm. Paddle is revolved at 50 RPM.

1 tablet is allowed to sink to the bottom of vessel an app. was run for 30 min. 10ml of sample is with drawn midway between dissolution medium and filtered 1 ml of filtrate is taken into l5ml vol flask and divided with po4 buffer. The absorbency of the solution was measured at 249 nm the con of this solution is calculated from standard curve further calculation are done to fix the % of paracetamol dissolved in 30 min.

REFERENCE:

The theory and practice of industrial pharmacy. By Lachmann & Liberman III edition, Indian pharmacopoeia 1996.