Spheronization or marumerization, is a rapid and flexible
process where pharmaceutical products are made into small
spheres, or spheroids of diameter ranging from about 0.5mm to
1mm where as in marumerizatin 0.6mm t0 1.2mm.
1. Optimum flow and handling characteristics:-
• The flow characteristics of spheres makes them suitable
for transportation by most systems found in the
pharmaceutical industry, including vacuum transfer.
2. More reproducible packing into small container:-
• The packing into small containers, such as hard gelatine
capsules, or larger packages is much more convenient than
other drug form such as powders or granules.
• Eliminate quality problems with variable dosage due to
packing problems with powder.
3. Minimum surface area/volume ratio:-
•Spheres provide the lowest surface area to volume
ratio and thus pharmaceutical compounds can be coated
with minimum of coating material. Important for effective
release of some drugs.
4. Optimum shape for coating and for controlled
•Coating can provide controlled, targeted release at
different location within the body.
•spheres are dense material that can easily be coated
within a minimum of coating material.
5.Easy mixing of non-compatible products:-
spherical particles are easily mixed.
6.Elimination of dust:-
Contamination is reduced.
The amount of fines and dust will be reduced
during transport and handling.
7.Improve hardness and friability:-
Spheronization increases the hardness and reduces
friability of granules.
Dry mixing of ingredients – to achieve a homogeneous powder
Wet massing – to produce a sufficiently plastic wet mass.
Extrusion – to form rod shaped particles of uniform diameter .
Spheronization – to round off these rods into spherical particles .
Drying - to achieve the desired final moisture content.
Screening -to achieve the desired narrow size distribution.
It produces rod shaped particles of uniform diameter from the
Wet mass is forced through the dies and shaped into small
cylindrical particles with uniform diameter .
The extrudate particles breaks at similar lengths under then
Extrudate must have enough plasticity to deform ,but extrudate
particles do not adhere to other particles when collected.
Based on their feed mechanism extruders divided into 3 types
1.screw feed extruder(axial and radial)
2.Gravity feed extruder (cylinder roll, gear roll and radial)
3.Piston feed extruder
2. Screen or basket extruder:-
Lower density extrudate.
Relatively high throughput.
3. Gear extruder:-
produces relatively high density.
Gears are robust and long lasting.
1.Screw feed extruder:-
•Commonly used in industrial
•High pressure and heat can degrade
Type of extruder used in pharmaceutical industry:-
Equipment Description Main uses
Extruder 20 Bench top screen
Extruder 35 Production screen
Lab /production , low cost
.high out put (2kg/min) of less
Extruder 40 Production gear
Quality extrudate output 40-
Extruder 100 Production gear
Quality extrudate output
Designed for pharmaceutical
process development work
Few dead spaces where
material can collect.
Minimum effective load
requirement is about 30g
Can be easily dismantled for
The mini screw extruder:-
For small quantity of material.
Smallest batch size can be extruded
is about 5g.
Material loaded into it manually.
Die hole size is 0.7mm to 2mm.
Minimum wastage of valuable
Can be quickly dismantled for easy
The primary extrusion process variables are :
1) The feed rate of the wet mass
2) The diameter of the die
3) The length of the die
4) The water content of the wet mass
THE SPHERONIZATION PROCESS:-
Machine consists of a rotating friction disk,
designed to increase friction with the
product, which spins at high speed at the
bottom of cylindrical bowl.
The ongoing action of particles colliding with the wall and being
thrown back to the inside of the plate creates a “rope-like”
movement of product along the bowl wall.
When particle have obtained the desired spherical shape,
discharge valve of the chamber is opened and the granules are
discharged by the centrifugal force.
The rounding of the extrudate into spheres is dependent on
frictional forces generated by particle- particle and particle
The bottom disc has a grooved surface to increase these
forces. Two geometric patterns are generally used.
1) A cross –hatched pattern with grooves running at right
angles to one another .
2) A radial pattern with grooves running radially from the
centre of the disc.
The transition from rods to spheres during spheronization
occurs in various stages
cylinder with rounded ends
In the fruend granulator ,the powder mix is added to the
bowl and wetted with granulating liquid from a spray.
The baseplate rotates at high speed and centrifugal force,
keeps the moist mass at edges of the rotor.
The velocity difference between the rotor and the static
walls, combined with the upward flow of air around the
rotor plate ,cause the mass to move in a toroidal
motion,resulting in the formation of spheres.
Standard features of marumerizer
Perfect cGMP design,smooth covering.
Explosion free design.
Automatic cleaning of entire system.
Completely integrated full opening side discharge.
Advance process for easy and automated granulation.
Integration with mill is possible.
Video monitoring the process.
Technical specifications for marumerizer:
0.5-3.2 3-10 5-20 15-50 10-40 30-100
Table summarizing the different types of caleva
spheronizers for pharmaceutical production and
Equipment Description Main use
Micro spheronizer --------- Laboratory:small
Spheronizer-120 Bench top Laboratory/experimental
Spheronizer-250 Lab scale bench top Low cost high output
Spheronizer-380 ------ Quality spheroids output
Spheronizer-500 ------- Quality spheroids output
Example of spheronizers:-
Key spheronization factors:-
1.Disc speed and load.
2.Disc groove geometry.
3.Disc diameter and speed.
1.Disc speed & load:-
There is an optimum disc speed and load for each disc
Momentum too low:-
Extrudate not densified sufficiently.
No spheres formed.
Momentum too high:-
Too much force on the granules.
Compression of particles within the granules.
The spheronizer drum charge volume:-
The optimum charging volume depends upon the machine size
and the product characteristics.
Ex-machine with a 380nm diameter disc, charged with a volume
of 4 liters. Depending on the density of the spheres and
smoothness of the granules.
2.Disc groove geometry:-
Square cross hatched design is most commonly used.
The particles must be plastic enough to allow deformation
during collisions, but also must be strong enough to
withstand collision with the disc, other particles & the
spheronizer wall without breaking up.
Typical spheronization retention time necessary to
obtained spheres is from 2 to 6 min .
The basic machine consist of a round disc with rotating
drive shaft ,spinning at the bottom of a cylindrical bowl.
This is most often cross hatched ,several sizes available.
These discs are designed to increase the friction with the
1)Friction plate pattern
2)Friction plate speed
4)The charge volume
1)Friction plate pattern:-
• The most common groove pattern used for spheroniser discs is
the “waffle-iron” or cross hatch design ,where the friction plate
is like a chessboard of chopped off pyramids.
• Discs with a radial design are also used.
2)Friction plate speed:-
• The typical rotation speed of a 700 mm diameter disc ranges
from 400 to 500 rpm.
• The optimum speed depends on the characteristics of the
product and the particle size.
Typical retention time to obtain spheres range from 2 to 6
The edges of cylindrical granules are the most fragile part and
they will generate dust during handling .
Spheronization with short retention time can help to reduce
4)The charge volume:-
The optimum level depends upon the machine size and the
Increasing the load per batch increases the hardness of the
spheres and smooths the granule surface.
The rheology of the product can be changed by varying
the formulation or physically.
Binders can be used to increase the strength of the
granules and reduce the amount of fines generated
during the process.
Lubricants will increase the plasticity.
Water can also be used as lubricant.
The optimum moisture content for spheronization is
slightly less than for extrusion.
These can help to improve the efficiency and ease of the
Warm water useful to drive off moisture that would cause
product sticking on the chamber wall.
Cooling the wall will avoid temperature rises in heat
The average temperature rise is generally rather
small(normally about 4 c).
It prevents dust from getting between the rotating plate
and the wall of the chamber .
It also help to remove moisture from the granule’s surface.
4)Non- stick coatings :-
The chamber wall and the spheronization plate can be
coated with non-stick materials if this is necessary for
ease of use with sticky materials or cleaning.
The design and manufacture of medicines (edited by
Michael.E Aulton),3rd edition.Aulton’s(pharmaceutics)
Inventi rapid:pharma tech journal ;review on extrusion
and spheronization (publication date 20-10-2012).
A literature review .,Chris Vervaet,Lieven Baert and Jean
Paul Remon.Interntional journal of pharmaceutics volume
116(28th march 1995).