An article by Laura Mercolini et al at the University of Bologna published in the August 2020 issue of Analyst, reported on a thorough validation of the suitability the hemaPEN® microsampling device for two serotonin reuptake inhibitors intended for therapeutic drug monitoring (TDM) applications. The paper is entitled “Assessment of capillary volumetric blood microsampling for the analysis of central nervous system drugs and metabolites.” It describes the development and validation of fluoxetine, norfluoxetine, sertraline and N-desmethylsertraline from dried blood extracted from DBS samples collected volumetrically using hemaPEN.
Being diagnosed with an incurable neurodegenerative disease is devastating for those affected and those close to them. The strain it causes can lead to severe anxiety and depression. Treatments given to CNS patients often have limited effect and may only treat symptoms. Other treatments may only slow down the progression of the disease. For example, the drug riluzole is one of the only treatments shown to extend life, to a limited degree, in patients with amyotrophic lateral sclerosis (otherwise known as motor neurons disease). If CNS conditions often occur later in life, older patients may already be taking a cocktail of drugs to treat other conditions, such as hypertension, high cholesterol and diabetes. Adding CNS-related medications to an already rigorous medication schedule can cause challenges or complications.
One such class of antidepressants are the second-generation antidepressants called serotonin reuptake inhibiters (SSRIs). The safety profiles of SSRIs are considered to be more favorable than many first-generation drugs, such as tricyclic antidepressants. SSRIs act by increasing levels of the neurotransmitter serotonin in the brain. Serotonin is associated with increased sense of wellbeing, increased appetite, and regulation of the body clock.
Use of dried matrix remote specimen collection and microsampling, whereby patient-collected specimens can be mailed to a central lab for analysis, helps care teams to more conveniently monitor drug levels in people. Remote microsampling has potential benefits for patients with CNS disorders. One such benefit is that as a CNS disease progresses, mobility and/or cognition become progressively hindered. As a result, clinic visits for onsite bloodwork and health checks become more challenging. With remote microsampling, people can collect their specimen samples in the comfort of their own homes and mail them in. This home sampling approach could be a game-changer for CNS patients and their carers.
To explore the possibilities, the team led by Laura Mercolini investigated the use of the hemaPEN as a potential remote microsampling device for monitoring two SSRIs and metabolites. The hemaPEN is an ideal patient-centric sampling tool for remote TDM. It simultaneously collects four capillary samples from a single source – a finger-prick, for example. After sampling, the end-user places the hemaPEN onto its plastic base and “clicks” it shut. This action transfers the four capillary samples onto 4 pre-cut DBS disks inside the hemaPEN, delivering four homogenous DBS samples secured in the device’s tamper-resistant housing that includes desiccant.
This device is easy to use by most patients, because hemaPEN sampling can be achieved at any angle without the fear of oversampling. In the lab, the internal DBS disks are removed from the device using a special opening tool. and the DBS samples are then extracted by pushing the disks from their cartridge into extractant in a workflow reminiscent of traditional DBS. The critical difference is that the hemaPEN allows for volumetric quantitation.
The authors should be commended on such a thorough analytical validation and device evaluation. The importance of providing patients with an option for self- or assisted sampling cannot be underestimated, especially for those who are debilitated with disorders that cause loss of mobility and/or cognition. Volumetric dried blood microsampling, whatever the chosen tool, really demonstrates the feasibility of how care can be continued remotely to allow those affected to minimize unnecessary travel to clinics and experience less invasive sampling. Moreover, remote devices offer the potential for more frequent sampling to further tailor treatment for those affected by devastating disorders.
This article was summarized for our readers by James Rudge, PhD, Neoteryx Technical Director. This is curated content. To learn more about the important research outlined in this blog, visit the original article in Analyst.
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