Tehran University of Medical Sciences Journal of Arthropod-Borne Diseases 2322-1984 20 1 2026 06 15 1926 1926 EN Seyedeh Zahra Parkhideh Department of Medical Entomology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran Mehdi Forouzesh Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Maryam Akhgari Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Kamran Akbarzadeh Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Ali Mohammad Ali Mohammadi Legal Medicine Research Center, Legal Medicine Organization, Tehran, Iran Sayena Rafizadeh Ministry of Health and Medical Education, Tehran, Iran Yavar Rassi Department of Vector Biology and Control of Diseases, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran, Arthropod-Borne Diseases Research Center, Ardabil University of Medical Sciences, Ardabil, Iran 2026 02 24 2026 06 12 Background: Entomotoxicology provides an alternative matrix for detecting drugs in decomposed human remains when conventional specimens are unavailable. This study aimed to develop and validate a quantitative method for de­tecting methamphetamine (MA) in different developmental stages of the blowfly Lucilia sericata. Methods: Immature stages of L. sericata (larvae, pupae, empty puparia) were reared on chicken liver spiked with MA at concentrations of 45, 90 and 180 ng/mg. Samples underwent liquid–liquid extraction, derivatization via acetylation, and analysis using gas chromatography-mass spectrometry (GC-MS). The method was validated according to interna­tional guidelines, evaluating limit of detection (LOD), limit of quantification (LOQ), linearity, precision, accuracy and repeatability. Results: The method showed strong linearity across the studied concentration range (R²= 0.9817–0.9934). The limit of detection and LOQ were 15 ng/mg and 45 ng/mg, respectively, with a relative standard deviation (RSD)≤ 20% at the LOQ level. Intra- and inter-day precision showed RSD values< 10%, and accuracy ranged from 98.55% to 100.73%. Methamphetamine was detected in all immature stages and empty puparia. The highest observed concentrations were detected in third-instar larvae and pupae, whereas no drug residues were detected in adult flies. Methamphetamine re­tention in empty puparia supports their potential forensic relevance for retrospective drug detection. Conclusion: This validated method demonstrated acceptable sensitivity, precision, accuracy and repeatability for quan­titative entomotoxicological analysis. The detection of methamphetamine across insect developmental stages suggests the suitability of this approach as a supplementary tool for forensic investigations involving decomposed remains. https://jad.tums.ac.ir/index.php/jad/article/view/1926 https://jad.tums.ac.ir/index.php/jad/article/download/1926/724