A Granulator is a multi-purpose processor equally suitable for high speed
dispersion of dry powders, aqueous or solvent granulations, effervescent
products, wet and melt pelletization.
Dry Mixing Whatever the subsequent
production steps, the formulation of an active compound and other excipients
needs to be mixed homogeneously. Low shear mixing relies on the planetary
movement of the mixer arm to achieve homogeneity, while high shear mixing uses
a high intensity mixing blade resulting in a homogeneous blend. Which technique
is most suitable depends on the subsequent production step. GEA Pharma
Systems Systems can assist in making the right choice.
Special
features:
Checking of
blend homogeniety by NIR-Technology
Low Shear Wet Granulation
During granulation, the active compound
and the other excipients are combined with a binder solution to form granules
with a fixed composition. Low shear planetary granulation is a gentle process
to achieve this goal.
High Shear Wet Granulation
The high shear granulation process
combines the components of the formulation using a high speed mixing blade and
chopper. This process results in granules of a fixed composition,
which
avoids segregation in later processing steps. During the granulation process,
density and compressibility of the product is modified to achieve the optimal
flow and tabletting properties.
Special features:
Control of granulation process via
in-line focus beam reflection measurement
Top Spray Granulation
The top spray fluid bed granulator
agglomerates finer particles into larger, free flowing granulates in a one-pot
process. Ingredients are mixed and pre-heated by an upward flow of heated air.
Granulation occurs by spraying liquid into the fluidized powder. The granules
are subsequently dried with heated air. The top spray granulator can also be
used for top spray coating, layering from liquids, and instantizing.
Special features
- One pot process
- Selection of air
distributors
Spray Dryer Granulation
The fluid bed spray dryer granulator
transforms suspensions or solutions into dry, freeflowing, dustless granules. A
suspension or solution of the substance to be dried is sprayed onto warm air,
simultaneously drying and agglomerating the product. Batch or continuous
discharge is available in the continuous mode, the product is discharged at a
controlled rate to maintain an optimum bed height.
Special features
- Compact unit
- Easy scale-up
- Batch or continuous discharge
Precision-Granulator™
A
rotating high velocity air stream is established in the central agglomeration
tube. Particles are picked up at the base of the tube and accelerated by the
air stream. The particles come into contact with liquid droplets produced from
the spray nozzle at the base of the tube \ the relative velocity of air, liquid
droplets and particles are high so wetting is efficient and drying begins
almost immediately. Most of the feed material is in the outer “holding area”,
where the gas velocity is very low. Attrition is greatly reduced. The gas
humidity is also low in the holding area so the material is dry not
sticky. Individual particles may make repeated cycles (typically from 10 to
1,000) through the tube, allowing very large agglomerates to be built up.
Melt Granulating
In a melt granulation process, the binder
solution of a standard wet granulation process is replaced with a meltable
binder. This binder can be added in molten form, but the high shear process
offers the benefit of allowing the binder to be added in its solid state.
Melting is achieved by the energy added through the mixer friction and the
heated jacket of the bowl.
Substrate Production for Extrusion
Planetary mixing is an
excellent method of producing the wet substrate needed for an extrusion
process, especially if this substrate needs to be a dough or paste. Special
mixing tools are available to enhance the mixing of doughs or
pastes.
Wet Pelletizing
This process uses a Niro Rotary Atomiser spray to
achieve excellent dispersion of binder liquid through the mix, and a special
high-speed rotation blade for maximum movement of the product, for more
efficient pelletization. A PTFE container-lining minimises the need for ‘top
and tailing’, even with the most cohesive of products. Studies have shown that
the PTFE liner - unique to Aeromatic-Fielder - can increase production
efficiency by as much as 40%.
Alternatively, an extruder may be used,
similar to those used for the manufacture of pellets. In a typical set-up all
ingredients are pre-blended in a container after dispensing. Depending on the
extruder design the liquid can be added in the extruder or mixed separately to
the correct consistency. The material produced by the extruder is now not
rounded in a spheronizer (as it would be for pellet manufacture) but
transferred directly into a continuous fluid bed where it is dried to the
desired moisture level.
Melt pelletization
This is an exceptionally fast method of
producing pellets in a single step. The active material and binder are mixed in
binder form then heated until the binder melts. A single batch is processed
typically in just 15-20minutes, and needs no further drying.
Dry Bonding
When low amounts of drugs should be administered via
inhalation, the accuracy of current devices is not precise enough. Therefore
the small drug particles are bonded to the course surface of lactose particles
in a dry high shear process. This requires special technology -
Aeromatic-Fielder’s expertise in this process provides; special impellers
giving enhanced shear forces, loading systems allowing a precise layering of
drug and excipient and often special containment devices such as Buck® split
valves or Hicoflex™.
Effervescent Products
One granulate method using water
A very small amount of water is added to start the pre-effervescent
reaction by which some of the carbondioxide is released during granulation, but
by which water is also produced as a reaction product, this then acts as a
granulation fluid producing more carbondioxide and also more water. This
avalanche needs to be stopped at a certain point by starting the drying process
and removing the water. This can be done using a high shear granulator with
subsequent fluid dryer by discharging at the end of the granulation process the
material into a pre heated fluid bed dryer.
Special note:
Technical article on Effervescent Production