2018 · Journal of pharmaceutical and biomedical analysis · paywalled
Extractability-mediated stability bias and hematocrit impact: High extraction recovery is critical to feasibility of volumetric adsorptive microsampling (VAMS) in regulated bioanalysis
Xie et al.
The finding, in our words
Low extraction recovery from VAMS caused apparent haematocrit bias and sample instability for raltegravir, but a modified liquid-liquid extraction method achieving over 80% recovery resolved these effects across a haematocrit range of 20 to 65% and was replicated for sitagliptin. This shows that extraction recovery must be optimised and verified as haematocrit-independent before VAMS is implemented in regulated bioanalysis.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
In lung and renal transplant recipients, VAMS sampling with LC-MS/MS quantification of mycophenolic acid and tacrolimus showed good linearity and accuracy, and with a haematocrit-adjusted conversion formula achieved clinical agreement in most samples; tacrolimus did not require haematocrit correction. The approach is virtually painless and enables richer sampling for more accurate drug exposure estimates, supporting decentralised therapeutic drug monitoring.
Juan et al., Journal of pharmacy & pharmaceutical sciences : a publication of the Canadian Society for Pharmaceutical Sciences, Societe canadienne des sciences pharmaceutiques · source ↗
This review found that volumetric microsampling devices, such as Mitra, HemaPEN, HemaXis DB10, and Tasso-M20, overcome haematocrit bias, whilst Telimmune plasma separation cards enable direct plasma collection without centrifugation. These technologies support patient-centric, decentralised sampling, though the authors note that clinical validation remains limited across different drugs and patient populations.
Huhn & Scherf-Clavel, Therapeutic drug monitoring (paywalled) · source ↗
The study validated an LC-MS/MS method for eight antiepileptic drugs and two metabolites in dried blood spot and VAMS formats, with satisfactory analytical performance and stability, and was the first to include the oxcarbazepine metabolite DHCB. In 80 paired patient samples, microsampling concentrations showed promising correlation with plasma, supporting decentralised therapeutic drug monitoring of antiepileptic treatment.
Cobo-Golpe et al., Journal of analytical toxicology · source ↗
The study developed and validated a rapid LC-MS/MS method for quantifying cefazolin in capillary whole blood collected via VAMS, plasma, and plasma ultrafiltrate, showing robust performance across matrices and successful application in a pediatric pilot cohort for therapeutic drug monitoring.
Kocur et al., Clinica chimica acta; international journal of clinical chemistry (paywalled) · source ↗
This study demonstrates that a commercial conductive vial electromembrane extraction device can reliably isolate basic pharmaceuticals from whole blood collected on volumetric absorptive microsampling tips, showing superior reproducibility and reduced matrix effects compared to conventional treatment.