15-01-2013, 02:23 PM
IPQC TESTS FOR TABLETS
IPQC TESTS.ppt (Size: 2.3 MB / Downloads: 126)
CHARACTERIZATION OF GRANULES
Particle Size & Shape Determination
Size affects the average weight of tablet, Disintegration Time, weight variation, friability, flowability & drying rate.
The size & shape depends upon processing requirements & during granulation.
The methods for determining size & shape are
1. Sieving
2. Sedimentation rate.
3. Microscopy (SEM)
4. By Light Scattering
Surface area
It is not commonly used for granules but generally used for drug substances.
If required particle size is measured & from this surface area is measured.
Most method used is gas absorption & air permeability.
In gas absorption, gas is absorbed as monolayer on particles this is in term of calculated & converted to surface area.
In air permeability method the rate of air permeates a bed of powder ,is used to calculate surface area of powder sample.
Density
Density may influence compressibility, tablet porosity & dissolution.
Dense hard granules may require higher load to produce cohesive compact to reduce free granules seen on the surface of tablets.
↑ compressibility ↑ DT, Dissolution, if DT is slower dissolution is indirectly hampered.
Dense granules have less friability but cause a problem in releasing the drug.
Three Methods to determine density
Bulk Density –
Bulk density is given by equation,
ρb = M / Vb
Where, ρb- bulk density of granules,
M is mass of granules in gm,
Vb – volume of granules in measuring cylinder in ml.
More compressible bed of particulate - less flowable powder or granules.
If less dense/compressible - more flowable powder or granules.
General Appearance:
The general appearance of a tablet, its identity and general elegance is essential for consumer acceptance, for control of lot-to-lot uniformity and tablet-to-tablet uniformity. The control of general appearance involves the measurement of size, shape, color, presence or absence of odor, taste etc.
Size & Shape:
It can be dimensionally described & controlled. The thickness of a tablet is only variables. Tablet thickness can be measured by micrometer or by other device. Tablet thickness should be controlled within a ± 5 % variation of standard value.
USP Dissolution apparatus II ( Paddle method)
It is same as apparatus-1, except the basket is replaced by a paddle. The dosage form is allowed to sink to the bottom of the flask before stirring. For dissolution test U.S.P. specifies the dissolution test medium and volume, type of apparatus to be used, rpm of the shaft, time limit of the test and assay procedure for. The test tolerance is expressed as a % of the labeled amount of drug dissolved in the time limit.