Oral PowderJect (OPJ) has been designed to deliver powdered drug to mucosal tissue in the mouth. Worldwide patents for the devices described below have been granted to PowderJect Pharmaceuticals plc.

There are several methods of accelerating powdered drug or vaccine particles to velocities high enough to penetrate skin or mucosal tissues. A shock tube forms the basis of the dermal PowderJect delivery device: it is capable of achieving high particle velocities in a jet of gas directed towards the target. However, the sudden release of this gas into the oral cavity was not considered desirable.