City Research Online

Optical determination of lithium therapeutic levels in micro‐volumes of interstitial fluid

Sheikh, M., Qassem, M. ORCID: 0000-0003-0730-3189 & Kyriacou, P. A. ORCID: 0000-0002-2868-485X (2023). Optical determination of lithium therapeutic levels in micro‐volumes of interstitial fluid. Bipolar Disorders, 25(2), pp. 136-147. doi: 10.1111/bdi.13291


Long-term management of bipolar disorder (BD), characterized by mood fluctuating between episodes of mania and depression, involves the regular taking of lithium preparations as the most reliable mood stabilizer for bipolar patients. However, despite its effectiveness in preventing and reducing mood swings and suicidality, lithium has a very narrow therapeutic index and it is crucial to carefully monitor lithium plasma levels as concentrations >1.2 mmol/L are potentially toxic and can be fatal. Current methods of lithium therapeutic monitoring involve frequent blood tests, which have several drawbacks related to the invasiveness of the technique, comfort, cost and reliability. Dermal interstitial fluid (ISF) is an accessible and information-rich biofluid, and correlations have been found between blood and ISF levels of lithium medication.

In the current study, we sought to investigate the optical determination of lithium therapeutic concentrations in samples of ISF extracted from porcine skin utilizing a microneedle-based approach. Monitoring of lithium levels in porcine ISF was achieved by employing a spectrophotometric method based on the reaction between the chromogenic agent Quinizarin and lithium.

The resulting spectra show spectral variations which relate to lithium concentrations of lithium in samples of porcine ISF with a coefficient of determination (R2) of 0.9. This study has demonstrated successfully that therapeutic levels of lithium in micro-volumes of porcine ISF can be measured with a high level of accuracy utilizing spectroscopic techniques.

The results support the future development of a miniaturized and minimally-invasive device for lithium monitoring in bipolar patients.

Publication Type: Article
Additional Information: © 2023 The Authors. Bipolar Disorders published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Publisher Keywords: bipolar disorder, interstitial fluid, lithium drug monitoring, personal monitoring, spectrophotometry
Subjects: R Medicine > RC Internal medicine > RC0321 Neuroscience. Biological psychiatry. Neuropsychiatry
Departments: School of Science & Technology > Engineering
SWORD Depositor:
[thumbnail of Bipolar Disorders - 2023 - Sheikh - Optical determination of lithium therapeutic levels in micro‐volumes of interstitial.pdf]
Text - Published Version
Available under License Creative Commons Attribution Non-commercial.

Download (2MB) | Preview


Add to AnyAdd to TwitterAdd to FacebookAdd to LinkedinAdd to PinterestAdd to Email


Downloads per month over past year

View more statistics

Actions (login required)

Admin Login Admin Login