Flowability Modification of Lactose Powder by Plasma Enhanced Chemical Vapor Deposition

The surface of 5.5 µm lactose particles was modified by gas phase reactions in a plasma enhanced chemical vapor deposition process to increase the flowability of the bulk solid. The particles were treated in the radio frequency plasma zone (RF) of a downer reactor, using a process gas mixture of oxygen, argon, and hexamethyldisiloxane (HMDSO). By increasing the flow rate of HMDSO (17–103 sccm) and the RF‐power (50–200 W), respectively, the flowability can be increased up to a factor of 2 compared to the untreated substrate material. No significant change in flowability was observed by varying the oxygen‐to‐HMDSO ratio from 5 to 30.