Micronization: particle size reduction
Micronization of a solid active pharmaceutical ingredient consists in the ingredient’s particle size reduction by means of a fluid jet mill.
The name Micronization derives from the action of the mill itself as the milling energy is the kinetic energy yielded to the particles by accelerating them with jets of compressed gas provided through nozzles placed in various positions around the milling chamber.
In these mills, the particles introduced into the circular chamber are accelerated and travel along a circular trajectory subject to a centrifugal force that tends to maintain them on the periphery.
Along the same trajectory the accelerated particle collides with other slower particles, or particles that are moving rapidly due to turbulence, and is fractioned into smaller particles that can escape the centrifugal force only when they have reached a certain mass. Then they move through the central outlet manifold towards the cyclone-filter where the solid parts are separated from the fluids.
In this way, the dual action of milling and particle classification is carried out simultaneously.
Fluid jet mills optimally comply with product safety regulations.
In fact, during micronization the temperature is controlled and since the equipment is made of stainless steel, it provides excellent grounding to discharge the electrostatic charges that form during processing. In addition, since there are no moving mechanical parts, the mills can be easily disassembled and cleaned, which makes it possible to set up adequate washing procedures to prevent possible contamination of the product that needs to be micronized.
Particle size reduction BENEFITS
The particle size distribution of an active pharmaceutical ingredient plays a key role in a successful formulation.
An appropriate particle size reduction accelerates the solubility rate of the active ingredient, which further improves the absorption and thus its bioavailability. This allows for a reduced amount of active ingredient in the formulation, limiting the drug’s side effects.
A pharmaceutical active ingredient has an inherent toxicity; therefore, its dosage in the finished formulation is of crucial importance.