Accurately delivering partial doses of a drug post dilution using an injector

A method for determining a maximum deliverable dose within a reservoir, the method comprising:

• providing a first substance within the reservoir having an initial dose value;
• introducing a second substance to the reservoir to produce a diluted solution;
• determining a total volume (VTotal), wherein the total volume is the sum of a volume of the first substance and a volume of the second substance;
• calculating the maximum deliverable dose within the reservoir based on the initial dose value and a ratio of a deliverable volume (VDeliverable) and the total volume (VTotal), and
• delivering up to the maximum deliverable dose to a patient through a fluid delivery system,
• wherein the fluid delivery system comprises the reservoir and a fluid path element in fluid communication with the reservoir and configured for delivering fluid from the reservoir to the patient.

A fluid delivery system comprising:

• a fluid reservoir configured for receiving a first substance having an initial dose value;
• a fluid conduit configured for introducing a second substance into the fluid reservoir to produce a diluted solution;
• a fluid delivery device having a fluid delivery conduit configured for delivering at least a portion of the diluted solution from the fluid reservoir to a patient;
• and
• a controller configured to determine a maximum deliverable dose capable of being delivered to the patient or non-deliverable dose that remains in the fluid reservoir,
• wherein the controller calculates the maximum deliverable dose or non-deliverable dose based on the initial dose value and at least two of a deliverable volume (VDeliverable), a non-deliverable volume (VNon-deliverable), a concentration of the diluted solution, a total dose, and a total volume (VTotal).