Dissolving microneedle patches are commonly characterized by the amount of active pharmaceutical ingredient incorporated, the fraction of needles judged to penetrate skin, and the extent of matrix dissolution. These measurements address different physical events and cannot, individually, establish the mass or time course of biologically accessible drug. This mechanism-based theoretical analysis examines how deformation of skin under an applied array, spatially heterogeneous penetration, contact with interstitial fluid, and formulation-dependent release jointly determine drug disposition. Drawing on published microneedle mechanics, polymer dissolution, pharmacokinetic, and carrier-delivery studies, the analysis distinguishes nominal loading, mechanically implanted cargo, dissolved matrix, liberated intact drug, local tissue deposition, and bioavailable exposure. It proposes a position- and time-resolved account in which these states may covary, making simple multiplication of average insertion and dissolution percentages potentially misleading. Rival insertion-limited, dissolution-limited, and post-release transport explanations are specified alongside discriminating measurement requirements. The resulting design principle is to verify pharmaceutical delivery at the anatomical and chemical state relevant to intended therapy, while treating penetration indicators and polymer disappearance as intermediate observations. The account remains a testable nonempirical synthesis; its relationships require formulation- and skin-context-specific validation.
IJPRAS
