Silver Nanocluster Probe Detects Clonazepam in Exhaled Breath Condensate

Researchers have developed a fluorometric probe based on chitosan-functionalized silver nanoclusters that can detect and quantify clonazepam in exhaled breath condensate, the liquid collected from a person’s exhaled breath. The work, published as open access research in BMC Chemistry on 6 October 2026, describes a new analytical route for monitoring this widely prescribed benzodiazepine through a non-invasive sampling matrix.

Clonazepam is a high-potency, long-acting benzodiazepine that enhances GABA-A receptor activity. It is approved for the short-term management of panic disorder, epilepsy, and nonconvulsive status epilepticus, and is also used off-label for conditions including restless leg syndrome, acute mania, insomnia, and tardive dyskinesia. Because the drug is eliminated slowly and has a narrow therapeutic range, accurate analytical methods are considered essential for therapeutic monitoring, a need the authors identify as the motivation for the study.

The silver nanoclusters at the heart of the probe were synthesized using a non-solvent-aided counter ion complexation method, with chitosan serving as the functionalizing agent. According to the abstract, the detection system responds to clonazepam, allowing the drug’s presence in exhaled breath condensate samples to be measured fluorometrically.

Before applying the method to real samples, the team carried out univariate optimization of the assay conditions and validated the procedure based on ICH guidelines, the international standards used for analytical method validation. The validated method was then applied to clonazepam analysis in exhaled breath condensate samples obtained from patients undergoing clonazepam therapy, demonstrating its intended use in a clinical monitoring context.

The study, authored by Maryam Radmanfard, Asal Naghipour Kordlar, Maryam Khoubnasabjafari, Vahid Jouyban-Gharamaleki, Elaheh Rahimpour, and Abolghasem Jouyban, was shared early under Springer Nature’s open access policy, meaning the peer-reviewed, accepted version is citable and carries a permanent DOI ahead of the final Version of Record. The article had recorded 45 accesses at the time of the source record.

Subject of Research: A fluorometric silver nanocluster probe for quantifying clonazepam in exhaled breath condensate for therapeutic monitoring

Article Title: Clonazepam-responsive fluorometric probe based on chitosan functionalized silver nanoclusters for its quantification in exhaled breath condensate

Article References: Radmanfard, M., Naghipour Kordlar, A., Khoubnasabjafari, M., Jouyban-Gharamaleki, V., Rahimpour, E., & Jouyban, A. (2026). Clonazepam-responsive fluorometric probe based on chitosan functionalized silver nanoclusters for its quantification in exhaled breath condensate. BMC Chemistry. https://doi.org/10.1186/s13065-026-01941-8

Image Credits: AI Generated

DOI: 10.1186/s13065-026-01941-8

Keywords: clonazepam, silver nanoclusters, chitosan, fluorometric probe, exhaled breath condensate, therapeutic drug monitoring, benzodiazepines, ICH validation, analytical chemistry, BMC Chemistry, Clonazepam-responsive, fluorometric