Rotor-stator homogenization

This review will focus on commonly used homogenizers in the pharmaceutical industry viz. high-pressure homogenizer, rotor-stator homogenizer, microfluid-izer, and ultrasonic homogenizer. 

Traditional methods of emulsification include high-pressure homogenizers, rotor-stator systems, and ultrasound homogenizers [110, 111], The first two examples employ high mechanical shear rates to produce small droplets of the... 

Copredpitation Batch mode vs. continuous mode Flow rate Droplet size distribution Mixer design (shear and energy, e.g., stir bar, vortex, propeller, homogenizer, rotor-stator) Solvent to antisolvent ratio Temperature Processing times (scale dependent)... 

The drug dissolved or dispersed in the melted lipid is poured into an aqueous emulsifier phase of the same temperature. By means of a rotor-stator homogenizer (e.g., an Ultra-Turrax), an o/w preemulsion is prepared and is then homogenized at high pressure and at a temperature at least 10°C above the melting point of the lipid. In most cases, nanoemulsion arises after only three to live homogenization cycles at 500 bar. Nanoparticles are formed by cooling the nanoemulsion to room temperature. 

Maa Y-F, Hsu C. Liquid-liquid emulsification by rotor/stator homogenization. J Contr Rel 1996 38 219-228. 

This group normally operates only under high shear conditions. Subclasses are differentiated by how the high shear is introduced into the material, such as by a dispersator with serrated blades or homogenizer with rotor stator. 

A less gentle, but widely used, solubilization device is the common electric blender. This method may be used for plant or animal tissue, but it is not effective for disruption of bacterial cell walls. A blender that is more scientifically designed is the rotor stator homogenizer. The stator is a hollow tube and the rotor, attached to the stator, is a rapidly turning knife blade. Cells are torn apart by the turbulence and shear generated by the rotor. 

Liquid/liquid emulsions consist of two (or more) non-miscible liquids. Classical examples for this are oil in water (O/W) emulsions, for example milk, mayonnaise, lotions, creams, water soluble paints, photo emulsions, and so on. As appliances, teeth-rimed rotor-stator emulsifiers and colloid mills, as well as high-pressure homogenizers are used. 

Fig. 49 Relationship d32 =/(Ap) for different emulsifiers. ZKDM-teeth ringed rotor-stator emulsifier, CM - colloid mill, HPH - high pressure homogenizer. Details on the material system in text from [74]...

In high force dispersion devices, ultrasonication is used today especially for the homogenization of small quantities, whereas rotor-stator dispersers with special rotor geometries, microfluidizers, or high-pressure homogenizers are best for the emulsification of larger quantities. 

The word homogenization is somewhat inconclusive and is typically defined as used in context. Two processes are considered here the first is a fine clearance valve homogenizer, and the second is a rotor-stator-type mechanical homo-genizer. Homogenization is similar to sonication and produces submicron droplets by a combination of mechanical shearing and cavitation. 

The rotor-stator-type mechanical homogenizer generates submicron droplets by forcing the emulsion through small openings in the stationary... 

Membrane emulsihcation has been recently proposed for the preparation of stable and uniform-sized microcapsules [27]. Membrane emulsihcation is a technology that allows to obtain uniform emulsions at low energy input compared to the emulsion prepared using high-pressure homogenizers and rotor/stator systems therefore, it is very useful for the preparation of emulsions containing labile compounds such as bioactive molecules sensihve to shear stress [28]. 

The rotor-stator homogenizer is one of the most commonly used pieces of equipment in the pharmaceutical industry. Although they have limited capability in achieving very fine droplets or particles, rotor-stator mixers are capable of handling liquids at much higher... 

Fig. 8 An in-line rotor/stator homogenizer. (IKA Works, Wilmington, NC.)...

Djakovic, Dokic, and Sefer studied several factors such as homogenization time, emulsifier concentration, and homogenization intensity to determine optimal parameters for emulsification, using a rotor-stator homogenizer. Mean droplet diameter and polydis-persity were used as measures of final product quality. For constant homogenization intensity (rpm) and... 

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