Rotor-stator homogenizers

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. 

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. 

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

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... 

Rotor/stator homogenizer Baffled mixed tank Static mixture... 

The other type of mechanical homogenizer is represented by the blade homogenizers ( blenders ) commonly used to produce extracts from plant and animal tissues. The cutting blades rotate at speeds of 6000-50 000 rpm. Blenders are not suitable for disruption of microorganisms unless glass beads or other abrasives are added to the media, but this leads to the same problems of foaming and aerosol formation as mentioned above for rotor-stator homogenizers (Yacko 2007). 

A solid microcarrier for encapsulating flavor-enhancing ingredients such as 5 -ribonucleotide was prepared from W/O/W emulsion using cacao butter as a melted lipid phase (Kukizaki et al., 2001). This microcarrier was used in Japan as a supplement in miso paste. The W/O emulsion with a mean particle size of 0.48 tm was produced at 40°C using a rotor-stator homogenizer. This W/O... 

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