Patch pump device for drug delivery

A patch pump for pumping liquid from a liquid reservoir to a subject for transcutaneous delivery of the liquid, the patch pump comprising:

• a first portion comprising a pump and a first cavity configured to receive a first end of the liquid reservoir, the pump comprising a piston pump comprising a plunger actuator configured to push a plunger into the liquid reservoir at the first end to cause the liquid to be expelled out the liquid reservoir;
• a second portion comprising a second cavity configured to receive a second end of the liquid reservoir, the second portion configured to be coupled to the first portion such that the liquid reservoir is held within the first portion and the second portion coupled together, the second portion configured to be separable from the first portion, the second portion comprising a tube configured to be fluidly connected to the liquid reservoir downstream from the liquid reservoir to, responsive to pumping by the piston pump that pushes the plunger into the liquid reservoir at the first end, receive the liquid expelled out of the liquid reservoir for supplying a dose of the liquid transcutaneously to the subject;
• and
• a housing support with an adhesive base configured to bond to the subject's skin for supporting the first portion and the second portion coupled together at the subject's skin,
• wherein the first portion is a reusable portion and the second portion is a disposable portion and further comprising a transcutaneous needle configured to be fixed directly to the disposable portion for transcutaneous delivery of the dose.