Fluid Bed Granulation Process

Introduction

There are many granulation technique available for pharmaceutical products - high shear granulation, fluid bed granulation, dry granulation etc. Where fluid bed granulation is a commonly used granulation technique in pharmaceutical industries. This article covers the following topics - 

● Fluidized bed granulator principle

● Fluidized bed granulation process parameters

● Fluidized bed granulation process steps

● Fluidized bed granulator advantages and disadvantages

Principle

Fluidized bed granulation is achieved by suspending the powder in the fluidized bed air and then binder solution is sprayed from nozzles that are either positioned above or below the powder bed depending on the type of the granulator.

Process Parameters

Following process parameters is to be checked during fluid bed spray granulation - 

● Machine Air Temperature (°C)

● Product Temperature (°C)

● Exhaust Temperature (°C)

● Exhaust Air Blower Speed (%)

● Machine Air flow (m3/hour)

● Atomization Air Pressure (bar)

● Spray pump speed (rpm)

● Spray Mass Flow (g/min)

● Exhaust Air Moisture (%)

● Inlet Air Moisture (%)

Steps

Fluidized bed granulation performed maintaining few steps successfully. Which include -

● Pre-heating

● Charging or loading

● Drymixing

● Spraying

● Drying

● Discharging

Fig: Fluid Bed Diagram

Advantages and Disadvantages of Fluid Bed Granulation

Advantages

● Robust process

● Granule size is easy to optimize the 

● Better flow 

● Smooth surface of granules

● Less drying time

Disadvantages

● Time consuming

● Slower Granules formation 

● Higher risk of lump formation due to overwetting

● Less granules strength