MANUFACTURING PROCESS QUALITY CONTROLS
QUALITY CONTROL TESTS
¾ Disintegration Test
¾ Dissolution Test
¾ Tablet Hardness and Friability
¾ Tablet Weight and Weight Variation Test
¾ Content Uniformity Test
¾ Tablet Thickness
Disintegration Test:
Disintegration test determines whether tablet disintegrate within the prescribed time when placed in a liquid medium. Disintegration is considered to be achieved when;
¾ No residue remain on screen
¾ If there is a residue, it consist of a soft mass having no palpably firm, unmoisture core sieve only fragments of coating remain on screen.
Test:
a) A riged basket rack assembly supporting six cylindrical transperant tubes 75-80 mm long, 21.5 mm in internal diameter. Wall thickness is about 2mm.
b) A cylindrical disk for each tube, each 20.55-20.85 mm in diameter and 9.35-9.65 mm thick, made for transparent plastic with a related density of 1.18-1.20, weighing 2.8-3.2g pierced with 5 holes, one in the center and other four spaced equally on the circle of radius 6 mm from the center of the disc.
c) The tubes are held vertically by two separate and superimposed rigid plastic plates 90mm in diameter and 6 mm thick.
d) The plates are held rigidly in position and 77.5mm apart by vertical metal rod at the periphery and metal rod is also fixed to center of upper plate to enable the assembly to be attached to a mechanical device capable of raising and lowering it smoothly through a distance of 50-60 mm at a constant frequency of between 25-30 cpm.
e) The assembly is suspended in a specific liquid medium. The volume of liquid is such that when the assembly is in highest position, the wire mesh is atleast 15mm below the surface liquid and when the assembly is in lowest position,
wire mesh is at least 25mm above the bottom of the beaker and the upper open ends of the tubes remain above the surface of the liquid.
Method:
Unless otherwise stated in the individual monograph, introduce one tablet into each of the 6 tubes and, if prescribed, add the disc to each tube. Suspend the assembly in the beaker containing the specified liquid and operate the apparatus for the specified time. Remove the assembly from the liquid. The tablet has passed the tst if all 6 have disintegrated.
Disintegration Test:
Apparatus:
Basket Rack Assembly Description:
The basket rack assembly consist of six open glass tubes each 7.75±0.25cm long having inside diameter of approximately 21.5mm and wall approximately 2mm thick.
The tubes are held in vertical position by two plastic plates, each about 9mm in diameter and 6mm in thickness, with 6 holes each about 24mm in diameter equidistant from the center of the plates and equally spaced from one another.
Procedure:
1. Replace the 10 mesh stainless steel cloth in the basket rake assembly with 40 mesh and also to the top of the assembly to provide for the insertion in the dissolution medium.
2. Adjust the apparatus so that it descends to 1±0.1cm from the bottom of the vessel on the downward stroke.
3. Use the medium as specified and proceed as directed in the individual monograph.
Tablet Hardness and Friability:
It is fairly common for a tablet press to exert as little as 3000 and as much as 4000 lb of force in production of tablet. Generally the greater the pressure applies, the harder the tablet is. Although the granulation also have a baring on hardness. In general tablets should be sufficiently hard to resist breaking during normal handling and yet soft enough to disintegrate properly after swallowing. Special dedicated hardness
tester or multifunctional systems are used to measure the degree of force required to break the tablet. Multifunctional automated equipments can determine weight, thickness, hardness and diameter of the tablet.
Tablet Weight and USP Weight Variation Test:
The quantity of fill in a die of a tablet press determines the weight of the tablet. The volume fill is adjusted with the first few tablets to yield the desired weight and content. During production, sample tablets are periodically removed for visual inspection and automated physical measurement.
The USP contain a test for determination of dosage form uniformity by weight variation for uncoated tablets. In this test, 10 tablets are weighed individually and the average weight calculated. The tablets are assayed and the contents of active ingredient in each of the 10 tablets are calculated assuming homogeneous drug distribution.
Content Uniformity:
By the USP method, 10 dosage units are individually assayed for their content according to the method described in the individual monograph. Unless otherwise stated in the monograph, the requirements for content uniformity are met if the amount of active ingredient in each dosage units lies within range of 85%-115% of the label claim and the standard deviation is less than 6%. If one or more units don’t meet these criteria, additional tests as prescribed in the USP are required.
Tablet Thickness:
The thickness of a tablet is determined by
¾ The diameter of the die,
¾ The amount of fill permitted to enter the die,
¾ The compaction characteristics of the fill material and
¾ The force or pressure applied during compression
To produce tablets of uniform thickness during and between batch productions for the same formulation, care must be exercised to employ the same factors ogf fill, die and pressure. The degree of pressure affects not only thickness but also hardness of the tablets; hardness is perhaps the more important criteria, since it can affect
disintegration and dissolution. Thus, for tablets of uniform thickness and hardness, it is doubly important to control pressure. Tablet thickness can be measured by hand gauge during production or by automated equipment