A container usable for lyophilization, storage, and reconstitution of medication having only two parts, one of which is a plug component having a flow path terminating in a side outlet port and a second of which is a barrel component. The barrel component has a spiral mixing channel near its distal end in which powder medication is stored and upon reconstitution, yields a gradient concentration. The inner wall of the barrel includes a longitudinal diluent groove. To connect the plug outlet port with the longitudinal diluent groove, the plug or barrel has a 360° distribution groove encircling the plug and connecting to the plug outlet port. Regardless of what rotational orientation the plug has to the barrel, the diluent will always reach the mixing channel.