Follow-up question based on your question: Medical Devices ALSO need approval from the FDA. Why is the Epi-Pen body not approved separately from the Drug, all

Follow-up question based on your question: Medical Devices ALSO need approval from the FDA. Why is the Epi-Pen body not approved separately from the Drug, allowing the body to be sold without epinephrine and to be filled with whatever, including generic epinephrine from a vial?