Quadro Engineering believes it has solved the "wet milling problem"
The machinery, named the Quadro Ytron HV-Emulsifier, uses rotor and stator technology and can process both wet mill solids in suspension and immiscible liquid solutions for emulsions, via a “quick” change of tooling.
Previously the rotor-stator configuration was thought unsuitable in wet milling for many compounds because the particle sizes it produced were too big – typically a mean volume (mv) of 28 – 35 microns.
Howeve,r by making some “minor adjustments” to the system, Quadro says it can input 55 times more energy than conventional equipment can stand and produce particles as small as mv 10 – 15 microns.
Speaking to in-PharmaTechnologist.com, liquids product manager Wilf Sangüesa said: “We pushed the envelope to see how fast we could run the machinery. It took design alterations, but we achieved results typical of other technologies but at a fraction of the capital investment and operating cost.
“Our tech has a stationary disk (the stator) and a rotating element (the rotor). They each have a set of teeth which are meshed within each other. As the fluid passes through the rotating teeth, energy is transferred to the API in the suspension, it gets mechanically reduced in size.”
He added that being able to process emulsions in the same machine is a “great advantage”, and said the high speeds are able to make very fine product often in the 200 to 500 nanometre range.
Milling revolution
Sangüesa said the development could mean an overhaul of the API milling industry, which has traditionally suffered from high costs due to inefficiency.
He said though media mills – which use either ceramic, or steel balls in a tumbler to break down the API over time – is one of the most popular wet mill technologies the process takes too long. Another popular method using high pressure homogenizers to push the liquid medium through a very small opening is costly and uses up to 20,000 PSI (pounds per square inch) pressures to break apart the API.
However with a host of benefits compared to dry milling – most notably the dust created during processing – Sangüesa believes developments in wet mill such as the HV-Emulsifier is the solution.
“One of the big draw backs is dusting,” he said. “APIs are so expensive now that when you waste just one per cent it’s a big deal. If you have $1m worth of product and you waste one per cent it’s a lot of money.
“Not only that, but when you have APIs and potent air born powders you need an isolator around the equipment, and that’s expensive both to buy and run.”
He added that though it is not possible to process all products in a wet mill or emulsifier, for those that can be there is almost zero API loss. And now with the new HV-Emulsifier, he said there is a cheaper and quicker way to do it.
