{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,5]],"date-time":"2026-11-05T20:52:09Z","timestamp":1793911929198,"version":"4.8.0"},"reference-count":38,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,2,8]],"date-time":"2026-02-08T00:00:00Z","timestamp":1770508800000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T00:00:00Z","timestamp":1770595200000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/100030902","name":"Martin-Luther-Universit\u00e4t Halle-Wittenberg","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100030902","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Sci Rep"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Cochlear implants (CIs) are the primary treatment for severe hearing loss. However, despite advances in electrode materials, implantation remains invasive and can cause trauma, inflammation, loss of residual hearing, and vestibular dysfunction. Foreign body reactions may lead to fibrosis, increasing electrode impedance and compromising device performance. To address insertion-related trauma, there is growing interest in developing electrode carriers that deliver drugs locally, such as dexamethasone, which has demonstrated efficacy in both preclinical and clinical settings. This study investigates a novel coating strategy to optimize the perilymphatic concentration\u2013time profile of dexamethasone and compares it to fully loaded silicone rods, in which the drug is incorporated within the silicone matrix. Silicone rods coated with 1.3\u00a0\u00b5g, 2.6\u00a0\u00b5g, or 5.2\u00a0\u00b5g dexamethasone were implanted into the scala tympani of guinea pigs. Drug concentrations were quantified over 84 days using liquid chromatography\u2013mass spectrometry (LC\u2013MS), and sequential sampling assessed distribution along the scala tympani. Coated rods exhibited an initial burst release, followed by a sustained steady-state phase. The 5.2\u00a0\u00b5g group peaked at 450 ng\/ml, decreasing to 50 ng\/ml by day 84. The 2.6\u00a0\u00b5g group showed a similar profile with proportionally lower levels. Sequential sampling at day 42 after implantation revealed that dexamethasone distributed throughout the length of scala tympani, forming a basal-apical gradient. Compared to fully loaded rods, the coated variants achieved comparable peak concentrations with substantially lower total drug amounts and a prolonged burst phase, which may enhance the suppression of the immediate inflammatory response following implantation. The improved pharmacokinetic efficiency likely also indicates a safer drug exposure profile.<\/jats:p>","DOI":"10.1038\/s41598-026-36620-0","type":"journal-article","created":{"date-parts":[[2026,2,8]],"date-time":"2026-02-08T22:04:07Z","timestamp":1770588247000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Long-term in vivo pharmacokinetics of dexamethasone-loaded cochlear implant electrode carrier dummies with optimized release profiles"],"prefix":"10.1038","volume":"16","author":[{"given":"Arne","family":"Liebau","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bernd","family":"Kammerer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michel","family":"Kather","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S\u00f6ren","family":"Schilp","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kenneth","family":"Mugridge","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susanne","family":"Braun","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eric","family":"Lehner","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stefan K.","family":"Plontke","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,2,8]]},"reference":[{"key":"36620_CR1","doi-asserted-by":"crossref","unstructured":"Bas, E. et al. Spiral ganglion cells and macrophages initiate neuro-inflammation and scarring following cochlear implantation. Front. Cell. Neurosci. 9, 303 (2015).","DOI":"10.3389\/fncel.2015.00303"},{"key":"36620_CR2","doi-asserted-by":"publisher","first-page":"323","DOI":"10.1097\/01.moo.0000244189.74431.df","volume":"14","author":"AA Eshraghi","year":"2006","unstructured":"Eshraghi, A. A. Prevention of cochlear implant electrode damage. Curr. Opin. Otolaryngol. Head Neck Surg. 14, 323\u2013328 (2006).","journal-title":"Curr. Opin. Otolaryngol. Head Neck Surg."},{"key":"36620_CR3","doi-asserted-by":"publisher","first-page":"328","DOI":"10.3109\/00016489.2015.1012276","volume":"135","author":"AA Eshraghi","year":"2015","unstructured":"Eshraghi, A. A. et al. Mechanisms of programmed cell death signaling in hair cells and support cells post-electrode insertion trauma. Acta Otolaryngol. 135, 328\u2013334 (2015).","journal-title":"Acta Otolaryngol."},{"key":"36620_CR4","doi-asserted-by":"publisher","first-page":"33","DOI":"10.1177\/000348941312200107","volume":"122","author":"H Jia","year":"2013","unstructured":"Jia, H. et al. Molecular and cellular mechanisms of loss of residual hearing after cochlear implantation. Ann. Otol. Rhinol. Laryngol. 122, 33\u201339 (2013).","journal-title":"Ann. Otol. Rhinol. Laryngol."},{"key":"36620_CR5","doi-asserted-by":"publisher","first-page":"284","DOI":"10.1097\/MAO.0000000000001686","volume":"39","author":"T Kamakura","year":"2018","unstructured":"Kamakura, T., O\u2019Malley, J. T. & Nadol, J. B. Jr. Preservation of cells of the organ of Corti and innervating dendritic processes following cochlear implantation in the human: An immunohistochemical study. Otol. Neurotol. 39, 284\u2013293 (2018).","journal-title":"Otology Neurotology"},{"key":"36620_CR6","doi-asserted-by":"crossref","unstructured":"Khan, A. M., Handzel, O., Damian, D., Eddington, D. K. & Nadol, J. B. Jr. Effect of cochlear implantation on residual spiral ganglion cell count as determined by comparison with the contralateral nonimplanted inner ear in humans. Ann. Otol. Rhinol. Laryngol. 114, 381\u2013385 (2005).","DOI":"10.1177\/000348940511400508"},{"key":"36620_CR7","doi-asserted-by":"publisher","first-page":"247","DOI":"10.1016\/j.otohns.2009.03.031","volume":"141","author":"JN Fayad","year":"2009","unstructured":"Fayad, J. N., Makarem, A. O. & Linthicum, F. H. Jr. Histopathologic assessment of fibrosis and new bone formation in implanted human temporal bones using 3D reconstruction. Otolaryngol. Head Neck Surg. 141, 247\u2013252 (2009).","journal-title":"Otolaryngol. Head Neck Surg."},{"key":"36620_CR8","doi-asserted-by":"crossref","unstructured":"Briggs, R. et al. Comparison of electrode impedance measures between a dexamethasone-eluting and standard Cochlear Contour Advance electrode in adult cochlear implant recipients. Hear. Res. 390, 107924 (2020).","DOI":"10.1016\/j.heares.2020.107924"},{"key":"36620_CR9","doi-asserted-by":"publisher","first-page":"313","DOI":"10.1080\/00016489850183386","volume":"118","author":"A Kawano","year":"1998","unstructured":"Kawano, A., Seldon, H. L., Clark, G. M., Ramsden, R. T. & Raine, C. H. Intracochlear factors contributing to psychophysical percepts following cochlear implantation. Acta Otolaryngol. 118, 313\u2013326 (1998).","journal-title":"Acta Otolaryngol."},{"key":"36620_CR10","doi-asserted-by":"publisher","first-page":"211","DOI":"10.1016\/j.wjorl.2017.12.008","volume":"3","author":"FH Linthicum","year":"2017","unstructured":"Linthicum, F. H. Jr., Doherty, J. K., Lopez, I. A. & Ishiyama, A. Cochlear implant histopathology. World J. Otorhinolaryngol. Head Neck Surg. 3, 211\u2013213 (2018).","journal-title":"World J. Otorhinolaryngol. Head Neck Surg."},{"key":"36620_CR11","doi-asserted-by":"publisher","first-page":"27","DOI":"10.1016\/j.heares.2013.01.012","volume":"298","author":"SJ O\u2019Leary","year":"2013","unstructured":"O\u2019Leary, S. J. et al. Relations between cochlear histopathology and hearing loss in experimental cochlear implantation. Hear. Res. 298, 27\u201335 (2013).","journal-title":"Hear. Res."},{"key":"36620_CR12","doi-asserted-by":"publisher","first-page":"225","DOI":"10.1016\/j.heares.2015.08.018","volume":"333","author":"AM Quesnel","year":"2016","unstructured":"Quesnel, A. M. et al. Delayed loss of hearing after hearing preservation cochlear implantation: Human temporal bone pathology and implications for etiology. Hear. Res. 333, 225\u2013234 (2016).","journal-title":"Hear. Res."},{"key":"36620_CR13","doi-asserted-by":"publisher","first-page":"12","DOI":"10.1016\/j.heares.2016.02.003","volume":"337","author":"E Bas","year":"2016","unstructured":"Bas, E. et al. Electrode array-eluted dexamethasone protects against electrode insertion trauma induced hearing and hair cell losses, damage to neural elements, increases in impedance and fibrosis: A dose response study. Hear. Res. 337, 12\u201324 (2016).","journal-title":"Hear. Res."},{"key":"36620_CR14","doi-asserted-by":"publisher","first-page":"195","DOI":"10.1179\/1754762813Y.0000000053","volume":"16","author":"D Douchement","year":"2015","unstructured":"Douchement, D. et al. Dexamethasone eluting electrodes for cochlear implantation: Effect on residual hearing. Cochlear Implants Int. 16, 195\u2013200 (2015).","journal-title":"Cochlear Implants Int."},{"key":"36620_CR15","doi-asserted-by":"crossref","unstructured":"Wilk, M. et al. Impedance changes and fibrous tissue growth after cochlear implantation are correlated and can be reduced using a dexamethasone eluting electrode. PLoS One 11, e0147552 (2016).","DOI":"10.1371\/journal.pone.0147552"},{"key":"36620_CR16","doi-asserted-by":"crossref","unstructured":"Prenzler, N. K., Salcher, R., Lenarz, T., Gaertner, L. & Warnecke, A. Dose-dependent transient decrease of impedances by deep intracochlear injection of triamcinolone with a cochlear catheter prior to cochlear implantation: 1 year data. Front. Neurol. 11, 258 (2020).","DOI":"10.3389\/fneur.2020.00258"},{"key":"36620_CR17","doi-asserted-by":"crossref","unstructured":"Liebau, A. et al. Long-term in vivo release profile of dexamethasone-loaded silicone rods implanted into the cochlea of guinea pigs. Front. Neurol. 10, 1377 (2020).","DOI":"10.3389\/fneur.2019.01377"},{"key":"36620_CR18","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1016\/j.jneumeth.2005.10.008","volume":"153","author":"AN Salt","year":"2006","unstructured":"Salt, A. N., Hale, S. A. & Plontke, S. K. Perilymph sampling from the cochlear apex: A reliable method to obtain higher purity perilymph samples from scala tympani. J. Neurosci. Methods 153, 121\u2013129 (2006).","journal-title":"J. Neurosci. Methods"},{"key":"36620_CR19","doi-asserted-by":"publisher","first-page":"182","DOI":"10.1007\/s10162-006-0034-y","volume":"7","author":"R Mynatt","year":"2006","unstructured":"Mynatt, R., Hale, S. A., Gill, R. M., Plontke, S. K. & Salt, A. N. Demonstration of a longitudinal concentration gradient along scala tympani by sequential sampling of perilymph from the cochlear apex. J. Assoc. Res. Otolaryngol. 7, 182\u2013193 (2006).","journal-title":"J. Assoc. Res. Otolaryngol."},{"key":"36620_CR20","doi-asserted-by":"crossref","unstructured":"Grzybowski, M., Malfeld, K., Lenarz, T., Scheper, V. & Schurzig, D. Optimization of pharmacological interventions in the guinea pig animal model: A new approach to calculate the perilymph volume of the scala tympani. Front. Neurosci. 17, 1297046 (2023).","DOI":"10.3389\/fnins.2023.1297046"},{"key":"36620_CR21","doi-asserted-by":"publisher","first-page":"245","DOI":"10.1159\/000493846","volume":"23","author":"AN Salt","year":"2018","unstructured":"Salt, A. N., Hartsock, J. J., Piu, F. & Hou, J. Dexamethasone and dexamethasone phosphate entry into perilymph compared for middle ear applications in guinea pigs. Audiol. Neurootol. 23, 245\u2013257 (2018).","journal-title":"Audiol. Neurootol."},{"key":"36620_CR22","doi-asserted-by":"publisher","first-page":"267","DOI":"10.1002\/jbm.b.33004","volume":"102","author":"L Astolfi","year":"2014","unstructured":"Astolfi, L. et al. Cochlear implants and drug delivery: In vitro evaluation of dexamethasone release. J. Biomed. Mater. Res. B Appl. Biomater. 102, 267\u2013273 (2014).","journal-title":"J. Biomed. Mater. Res. B Appl. Biomater."},{"key":"36620_CR23","doi-asserted-by":"publisher","first-page":"25","DOI":"10.1016\/j.heares.2017.12.010","volume":"362","author":"AN Salt","year":"2018","unstructured":"Salt, A. N. & Hirose, K. Communication pathways to and from the inner ear and their contributions to drug delivery. Hear. Res. 362, 25\u201337 (2018).","journal-title":"Hear. Res."},{"key":"36620_CR24","doi-asserted-by":"publisher","first-page":"28","DOI":"10.1016\/j.heares.2018.03.002","volume":"368","author":"AN Salt","year":"2018","unstructured":"Salt, A. N. & Plontke, S. K. Pharmacokinetic principles in the inner ear: Influence of drug properties on intratympanic applications. Hear. Res. 368, 28\u201340 (2018).","journal-title":"Hear. Res."},{"key":"36620_CR25","doi-asserted-by":"publisher","first-page":"722","DOI":"10.1097\/MAO.0000000000002624","volume":"41","author":"AN Salt","year":"2020","unstructured":"Salt, A. N. & Plontke, S. K. Steroid nomenclature in inner ear therapy. Otol. Neurotol. 41, 722\u2013726 (2020).","journal-title":"Otol. Neurotol."},{"key":"36620_CR26","doi-asserted-by":"crossref","unstructured":"Salt, A. et al. Perilymph pharmacokinetics of marker applied through a cochlear implant in guinea pigs. PLoS One 12, e0183374 (2017).","DOI":"10.1371\/journal.pone.0183374"},{"key":"36620_CR27","doi-asserted-by":"publisher","first-page":"44","DOI":"10.1016\/j.heares.2016.04.005","volume":"336","author":"L Astolfi","year":"2016","unstructured":"Astolfi, L. et al. Cochlear implant and inflammation reaction: Safety study of a new steroid-eluting electrode. Hear. Res. 336, 44\u201352 (2016).","journal-title":"Hear. Res."},{"key":"36620_CR28","doi-asserted-by":"crossref","unstructured":"Behrends, W. et al. Dual drug delivery in cochlear implants: In vivo study of dexamethasone combined with diclofenac or immunophilin inhibitor MM284 in guinea pigs. Pharmaceutics 15, 726 (2023).","DOI":"10.3390\/pharmaceutics15030726"},{"key":"36620_CR29","doi-asserted-by":"publisher","first-page":"3443","DOI":"10.2147\/DDDT.S318117","volume":"15","author":"Y Huang","year":"2021","unstructured":"Huang, Y. et al. Hearing protection outcomes of analog electrode arrays coated with different drug-eluting polymer films implanted into guinea pig cochleae. Drug Des. Devel. Ther. 15, 3443\u20133450 (2021).","journal-title":"Drug Des. Devel Ther."},{"key":"36620_CR30","doi-asserted-by":"publisher","first-page":"89","DOI":"10.1016\/j.heares.2015.04.019","volume":"327","author":"Y Liu","year":"2015","unstructured":"Liu, Y. et al. Effects of a dexamethasone-releasing implant on cochleae: A functional, morphological and pharmacokinetic study. Hear. Res. 327, 89\u2013101 (2015).","journal-title":"Hear. Res."},{"key":"36620_CR31","doi-asserted-by":"publisher","first-page":"45","DOI":"10.1179\/1754762811Y.0000000024","volume":"14","author":"M Farhadi","year":"2013","unstructured":"Farhadi, M. et al. Dexamethasone eluting cochlear implant: Histological study in animal model. Cochlear Implants Int. 14, 45\u201350 (2013).","journal-title":"Cochlear Implants Int."},{"key":"36620_CR32","doi-asserted-by":"publisher","first-page":"61","DOI":"10.2165\/00003088-200544010-00003","volume":"44","author":"D Czock","year":"2005","unstructured":"Czock, D., Keller, F., Rasche, F. M. & H\u00e4ussler, U. Pharmacokinetics and pharmacodynamics of systemically administered glucocorticoids. Clin. Pharmacokinet. 44, 61\u201398 (2005).","journal-title":"Clin. Pharmacokinet."},{"key":"36620_CR33","doi-asserted-by":"publisher","first-page":"874","DOI":"10.1002\/jps.2600501018","volume":"50","author":"T Higuchi","year":"1961","unstructured":"Higuchi, T. Rate of release of medicaments from ointment bases containing drugs in suspension. J. Pharm. Sci. 50, 874\u2013875 (1961).","journal-title":"J. Pharm. Sci."},{"key":"36620_CR34","doi-asserted-by":"publisher","first-page":"6","DOI":"10.1016\/j.ijpharm.2011.03.051","volume":"418","author":"J Siepmann","year":"2011","unstructured":"Siepmann, J. & Peppas, N. A. Higuchi equation: Derivation, applications, use and misuse. Int. J. Pharm. 418, 6\u201312 (2011).","journal-title":"Int. J. Pharm."},{"key":"36620_CR35","first-page":"5733","volume":"7","author":"J Sun","year":"2012","unstructured":"Sun, J. et al. Effect of particle size on solubility, dissolution rate, and oral bioavailability: Evaluation using coenzyme Q10 as naked nanocrystals. Int. J. Nanomed. 7, 5733\u20135744 (2012).","journal-title":"Int. J. Nanomed."},{"key":"36620_CR36","doi-asserted-by":"publisher","first-page":"311","DOI":"10.1016\/j.otc.2018.11.008","volume":"52","author":"C Li","year":"2019","unstructured":"Li, C., Kuhlmey, M. & Kim, A. H. Electroacoustic stimulation. Otolaryngol. Clin. North Am. 52, 311\u2013322 (2019).","journal-title":"Otolaryngol. Clin. North. Am."},{"key":"36620_CR37","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1159\/000327765","volume":"16","author":"CA von Ilberg","year":"2011","unstructured":"von Ilberg, C. A., Baumann, U., Kiefer, J., Tillein, J. & Adunka, O. F. Electric-acoustic stimulation of the auditory system: A review of the first decade. Audiol. Neurootol. 16, 1\u201330 (2011).","journal-title":"Audiol. Neurootol."},{"key":"36620_CR38","doi-asserted-by":"publisher","first-page":"2889","DOI":"10.1002\/lary.31263","volume":"134","author":"A Micuda","year":"2024","unstructured":"Micuda, A., Li, H., Rask-Andersen, H., Ladak, H. M. & Agrawal, S. K. Morphologic analysis of the scala tympani using synchrotron: Implications for cochlear implantation. Laryngoscope 134, 2889\u20132897 (2024).","journal-title":"Laryngoscope"}],"container-title":["Scientific Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-36620-0","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-36620-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-36620-0.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,9]],"date-time":"2026-02-09T10:44:50Z","timestamp":1770633890000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.nature.com\/articles\/s41598-026-36620-0"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2,8]]},"references-count":38,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2026,12]]}},"alternative-id":["36620"],"URL":"https:\/\/doi.org\/10.1038\/s41598-026-36620-0","relation":{},"ISSN":["2045-2322"],"issn-type":[{"value":"2045-2322","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2,8]]},"assertion":[{"value":"16 June 2025","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"14 January 2026","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"8 February 2026","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"The study was financed by MED-EL Medical Electronics, Innsbruck, Austria. SS, KM, and SB were employed by MED-EL at the time of the study. The study design was planned in consultation with MED-EL. MED-EL did not influence data analysis or publication of data. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}},{"value":"The animal study was conducted in accordance with the German Animal Welfare Law and ARRIVE guidelines and were approved by the Saxony-Anhalt State Office for Consumer Protection and Veterinary Affairs, Germany (reference 42502-2-1207MLU). The results were reported in accordance with ARRIVE guidelines.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval"}}],"article-number":"5424"}}