The endpoint finding of wet granulation is very important to form good-quality granules and retain the same quality when repeated batches are manufactured. The endpoint is regulated during wet granulation after the addition of binder solution /solvent.
Mixing time after the addition of binder solution/solvent should be optimum because over-mixing may develop hard granules and under-mixing may generate more fine than granules.
Different methods and techniques are used to monitor endpoint some are described as follows,
Power Consumption
The power consumption of the mixer motor is used to define the endpoint and it is associated with the granules growth.
Torque Value
Torque value of impeller is also a significant factor to determine the endpoint.
Solvent/Binder addition Time
To assure consistent endpoint addition of binder solution/solvent plays an important role. Binder addition rate control granules density. Slow binder solution addition rate is suggested to prevent local over-wetting.
Kneading Time
Higher mixing time after binder solution addition results in a decrease in intra-granular porosity and increase in granules size and strength.
Hand Squeeze Method/Banana Technique
It is an old and most commonly used method to determine the endpoint of granulation, in this method wet mass is squeezed in hand and then lumps are broken down to physically check the quality of granules, there should be no dry powder or fine powder. This method depends on operators skills and can not be validated.
- Lactose as a diluent in tablet granulation.
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Use of microcrystalline cellulose in pharmaceutical products.