What are the Components of a Granulation Suite?

Granulation is the process of enlarging the particle size of powder by various techniques in pharmaceutical industry. It transforms the powder into a form that can be easily used for further processes, and the equipment used to form this process is called Granulation Suite.

Granulation Suite is one of critical and important line of equipment in pharmaceutical industry. They are mainly used in the manufacturing of Oral Solid Dosage forms, and plays an important role in the quality, efficacy and safety of these products.

What is a Granulation Suite?

Granulation suite is a combination of different machines that are connected with each other in a serial manner. It means the output of one stage becomes the input of next level machine. Each machine is designed to perform a specific function according to the process and product requirement, and combines various components of formulation in a single product.

Like other equipment and process, the quality of product is required to be measured at machine level. Otherwise, it will affect the quality and product characteristics of the final finished form. For this purpose, the quality department keeps a check on the production at each machine level. The output is not allowed to advance to its next stage until checked and verified by the Quality department.

Like other pharmaceutical equipment, its product contact parts are made up of Stainless Steel 316L. Because, it resists corrosion, rusts and reaction with the product. If SS316L is not used, it will damage the product and product cannot be used for human consumption.

Components of a Granulation Suite?

As discussed above a granulation suite consist of series of machines that works serially with respect to each other and commonly consists of the following

High Shear Mixer granulator - HSMG

High Shear Mixer Granulator - HSMG is a machine, where powder is mixed with each other, or with different chemical powders. In this machine, liquid is also added during the process which acts as a binder. The purpose of binder is to make bond between different chemicals and is applied with a dedicated nozzle.

HSMG consists of different parts that aids in a successful operation and consist of the following

Bowl: it is a large metallic container that contains material, and mixing take place in this bowl.

Impeller: it is a rotating part inside the bowl which is equipped with blades. It can rotate at varying speeds, depending up on the process requirement

Chopper: It is a small rotating part, usually installed at one side of bowl, or near the impeller. Its main purpose is to cut lumps into smaller granules. Usually chopper rotates at fixed speed, or at two speed level - one is called high another is called low

Nozzle: It is used to add liquid in granules during the mixing process which is added as per the process requirement

The powder is added to the bowl and impeller is started. The mixing occurs due to the affect of rotating impeller, which rotates at variable speed. Chopper is also started and facilitates uniform granules by cutting large lumps into smaller. Liquid is also a added during the process, at varying speed that depends on the process requirement.

Fluid Bed Dryer

Fluid Bed Dryer is used to reduce the moisture content in the mixture of the powder, by the effect of hot air, that passes through the powder mixture. The moisture  escapes the container through the exhaust

When hot air passes through the powder material, it starts to float in the product container and takes the form of fluid, which is why the machine is called Fluid Bed Dryer. The fluid shape facilitates the drying process, because every particle, from every dimension is exposed individually to heat and increases the heating efficiency, takes less time to complete the process.

During the process moisture content is continuously monitored to prevent over or under drying. When material has been dried to its required moisture level, heating is stopped and material is discharge from FBD for further processing.

FBD also consists of instrumentation system to monitor the process during drying process and mainly consists of the following

• Temperature sensor to monitor the temperature of incoming air, product and exhaust air

• Flow sensor to monitor the flow of air across various section of FBD

• Pressure at different section and filters to verify integrity of process and filters

Since it uses hot air, the design of FBD is a bit complicated as compared to other machines, in granulation suite and mainly consists of the following parts

• Air handling unit

• Main machine

• Exhaust unit

Air handling unit is a system through which air is generated. It consists of a blower that generates the required volume of air, and passes through series of filters including the HEPA. The filters purify the air, because product comes in direct contact with the air, and are necessary to prevent contamination.

Main machine consist of a Stainless Steel container in which product is contained for drying. The product container is perforated from below from which hot air passes through the container. The product container receives air  from the AHU, which is connected to the product container through appropriate duct system

The exhaust unit sucks the air from the product container, and exhausts it into the environment. Exhaust unit also contain filters to prevent chemically active materials from going into the environment. The product container is conducted to exhaust unit through duct system. In the duct system, bag filters are attached above product container, and are used to prevent powder going into the exhaust unit. During the process, these filters are shake automatically to drop powder that have been attached to them. Additional instruments such as temperature and air flow are also use to monitor the drying process.

Blender

The next machine after fluid bed drying is the blender. It is used to mix or blend the material to form a homogeneous mixture. The mixing process occurs due to tumbling of mechanical structure, which in turn tumbles the powder material inside the blender.

The material is inserted to the differently shaped container, which is attached to the rotating shaft driven by motor. Mixing is stopped after pre-determined timer, and after inspecting the physical condition of powder, the material discharge from the container.

Types of blender

In Pharmaceutical industry, there are different types of blender that depends upon the shape of the blender and includes the following

V Blender

Consists of cylindrical shaped bin, joined together from one end, creating a v shape. The other end is connected to the rotating shaft.

Octagonal blender

As the name suggest, this blender is in octagonal shape. This type allows to load larger quantities of powder and occupies less space as compared to other blender types

Double cone blender

Double cone blender take the form of a double cone, and is attached to the rotating shaft from its middle.

Ribbon blender

Ribbon blender consist of mixing ribbons attached to a central rotating shaft. One set of ribbon move inward,  while other move outward. As they move inward and outward, the material also move inward and outward, and material is also mixed corresponding to the ribbon movement.

Sifter

A sifter is a machine that is used to separate small particle chemical from large particles or lumps. Just like a normal condition in which sieve is used to separate small and large material, it also consists of a sieve inside it.

The sieve is also called vibro-sifter, because it vibrates during its operations.

It is a horizontal machine with infeed from upside and sieve in between. Spring present inside the machine (between infeed and sieve) create the effect of operation and material from infeed moves toward the sieve and passes through it. The particle size that matches the sieve size, easily pass through it and are collected through outfeed.

Particles that do not pass are collected through a separate discharge port. The machine is operated through motor, whose speed can be varied according to process requirement.

Cone Mill

Cone Miss is used to mill the powder particle in order to make uniform size, and is typically used after HSMG. The size of particle that can be generated depends upon the cone inside it.

The cone - mill can be used in two configuration offline and online

In online mechanism the material is directly transfer to the mail without transferring to any storage medium. This is achieved by directly connecting to the machine or transferring material through vacuum transfer system.

In offline configuration, the material does not directly goes into the mill. Instead, first it is stored into another container, and then the material is milled.

Roller Compactor

A roller compactor is a machine used to combine different chemical into a single product, typically used to combine active with excipient. Additionally, in this process, liquid is not used and only dry compaction is performed.

It consists of two roller that rotates with force against each other. The material to be compacted enters from one side, and as it passes through these rollers, the material is compacted. The resultant material is in a form of different sized flakes, which is further milled to convert into uniform sized particles.

About the Author

Muhammad Asim Niazi has a vast experience of about 11 years in a Pharmaceutical company. During his tenure he worked in their different departments and had been part of many initiatives within the company. He now uses his experience and skill to write interested content for audiences at PharmaSources.com.