Which is the best way to transfer potent powders?

Powder transfer is a common operation in the pharmaceutical and in the fine chemical industries. Powder gets transferred at different steps during the manufacturing process: first when raw materials are first introduced in the production equipment, then intermediates are transferred from one vessel to another and finally when the final product is collected and dispensed.

Potent powder handling can be hazardous operation. You have to consider a few different factors such as the potency of the product, the quantities involved and the task duration. The higher those are the larger is the risk of harmful exposure.

By the way the potency of a product is expressed by the OEL (it stands for Occupational Exposure Level), which defines the maximum quantity of product to which an operator can be safely exposed for a certain period of time.

Potent raw materials can be handled through simple charging/unloading isolators: once the drum is opened and lifted, the product bag can be connected to a flange installed on the rear of the charging isolator and the product poured in the process vessel.

Potent intermediates may need to be transferred from one contained system (isolator) to another. Safety devices such as rapid transfer ports or split valves are used in this case for the safe transfer of small amounts of drugs.

Finished products that must be packed into drums require different solutions based on their potency. Non potent compounds can be directly discharged into the final product bag through a pack-off system or a simple isolator. Highly active APIs need to be packed with a double bag system in a single or double chamber isolator.

There is no standard technology for the safe handling of powders. Containment manufacturers together with their customers shall conduct a HAZOP evaluation to design the proper solution specific to the process.