Drug-delivery innovation is commonly judged through formulation performance, pharmacokinetics, dosing interval, device functionality, safety, or therapeutic efficacy. These achievements are necessary for translation but do not establish that a technology can be delivered repeatedly within ordinary care. This critical interpretive synthesis examined how product requirements interact with patient capabilities and health-system conditions after credible technical or clinical performance has been demonstrated. Targeted searching identified 112 records or documents. After removal of 37 duplicate or version-equivalent records, 75 unique records were screened and 51 underwent in-depth assessment. Thirty-one core sources were retained, and five purposive or theoretical sources were subsequently added, yielding a final synthesis corpus of 36 evidence sources. The synthesis distinguished technical performance from the recurrent work required to preserve that performance in practice. Across long-acting injectable therapy, microneedle and microarray-patch vaccination, inhaler-based delivery, continuous glucose monitoring, and self-injected contraception, recurrent requirements included administration competence, appointment capacity, storage and supply logistics, reimbursement processes, monitoring infrastructure, data interpretation, and patient willingness or capability. Several technologies successfully shifted work away from clinics, demonstrating that operational complexity does not inevitably impede adoption. Conversely, strong efficacy or attractive dosing intervals did not remove the need for reliable service capacity. The evidence supports a conditional interpretation of translation failure: technically successful delivery systems become workable routine care when their technology-specific recurrent requirements can be sustained by the patient, care team, and service environment. The relevant translational question is therefore not whether an innovation is intrinsically simple or complex, but whether the work it requires is feasible where care is actually delivered.
