The Flow Moderator is an essential part of the ALZET pump. It is comprised of a stainless steel tube with a plastic cap and/or flange on one end, depending on the pump model. Its purpose is twofold. The stainless steel tube provides capillary action, which prevents the test solution from leaking out of the pump reservoir. The flow moderator also provides a means for attaching to a catheter for targeted delivery applications.
The Filling Tube is a blunt-tipped needle specially designed and cut to the appropriate length for each ALZET pump size. It has a hub for attaching to a syringe for filling the pump with the desired test solution. Each box of 10 pumps comes with one filling tube. Additional filling tubes may be purchased as needed, and they are available in multiples of 10. Note that ALZET pumps should only be filled with these specially designed filling tubes.
When using ALZET pumps during MRI, it will be necessary to replace the stainless steel flow moderator with non-metallic tubing of the same length and outer diameter as the original flow moderator. One such material is PEEK (polyetheretherketone) medical microtubing, which is available from DURECT Corporation as listed below.
Click here for a detailed procedure for replacing the stainless steel tube with the MRI-compatible part for use during MRI studies.
When using ALZET pumps for bio-luminescence imaging (BLI) applications, researchers should use the BLI-compatible flow moderators in blue or teal color. These were specifically developed to avoid background luminescence caused by the standard (white) flow moderators, which may interfere with the real signal from the biological system under study.
