MDPHP in Post-Mortem Tissues and Necrophagous Larvae After Advanced Decomposition: LC-HRMS Findings and Tentative Phase-I Metabolites

Abstract

Background/Objectives: 3,4-Methylenedioxy-alpha-pyrrolidinohexanophenone (MDPHP) is a pyrrolidinophenone synthetic cathinone whose post-mortem interpretation is particularly difficult when advanced decomposition prevents blood-based toxicology. This case report examined instrument-derived semiquantitative MDPHP values in solid tissues and necrophagous larvae and assessed the complementary evidential value of larval matrices. Methods: Post-mortem computed tomography, complete autopsy, histology, and liquid chromatography–high-resolution mass spectrometry (LC-HRMS) were performed in an adult decedent found in advanced decomposition. Brain, liver, kidney, and four separately collected larval groups were analyzed using a procedure previously validated in blood but not validated in tissues or larvae. Results: No fatal traumatic lesion was identified. Pulmonary edema and myocardial fibrofatty replacement were documented. Instrument-derived semiquantitative MDPHP values were 0.45 ng/mg in brain, 0.75 ng/mg in liver, and 2.44 ng/mg in kidney; the four larval groups yielded <0.06, 0.43, 1.58, and 0.22 ng/mg, respectively. These values are exploratory and semiquantitative because matrix-specific validation data are unavailable. The Larvae III extract also showed signals tentatively assigned to M3.1, M5.2, and M9.1. Conclusions: Necrophagous larvae preserved evidence of MDPHP exposure and phase-I metabolite signals. The findings do not establish validated quantitative concentrations, a lethal threshold, or a tissue-to-larva relationship. In the integrated medicolegal context, MDPHP intoxication remained a plausible contributor, but causal interpretation was limited by the single-case design, decomposition, underlying myocardial pathology, absence of conventional matrices, and lack of tissue- and larva-specific method validation.