A sensitive liquid chromatographic-mass spectrometry method for the quantification of vincristine in whole blood collected with volumetric absorptive microsampling

An on-line SPE-LC-MS method using 10 microlitre capillary blood samples collected on VAMS tips achieved lower limits of quantitation of 0.03 micromolar for methotrexate and 7-OH-MTX and 0.05 micromolar for DAMPA, with acceptable accuracy and precision. A plasma-to-whole-blood correlation factor of 0.46 was observed, supporting low-volume pediatric drug monitoring.

Development and validation of a bioanalytical method for the quantification of methotrexate from serum and capillary blood using volumetric absorptive microsampling (VAMS) and on-line solid phase extraction (SPE) LC-MS — Opitz et al., Journal of chromatography. A (paywalled) · source ↗

• blood
• dried
• capillary
• vams
• neoteryx-mitra
• validation
• pediatric
• tdm
• oncology

In AML and CLL, 91% of VAMS venetoclax results fell within 20% of plasma after individualised haematocrit correction; in home sampling, 18 of 21 patients self-sampled independently and 76% of returned samples were analysable, which shows home microsampling is workable, though the authors ask for multicentre validation.

Clinical Validation of Venetoclax Volumetric Microsampling in Leukemia, with Whole-Blood-to-Plasma Conversion and Self-Microsampling Feasibility — Levens et al., Clinical Pharmacokinetics (paywalled) · source ↗

• vams
• venous-agreement
• blood
• dbs
• tdm
• self-collection
• haematocrit
• dried
• oncology
• capillary
• validation

This study found that volumetric absorptive microsampling shows satisfactory agreement with venous plasma for monitoring several antiseizure medications in paediatric patients. However, a blood-to-plasma conversion factor was required to estimate plasma concentrations for clobazam and carbamazepine metabolites due to poor capillary-to-plasma interchangeability.

Volumetric Absorptive Microsampling (VAMS) for Therapeutic Drug Monitoring of Antiseizure Medications (ASMs) in Pediatric Patients — Simeoli et al., Pharmaceuticals (paywalled) · source ↗

• blood
• dried
• vams
• validation
• venous-agreement
• pediatric
• tdm

An LC-MS/MS method for tamoxifen and six metabolites in VAMS was developed and validated, with water prerinsing improving recoveries and poor room temperature stability but stability for at least 100 days at minus 80 degrees Celsius. Plasma to blood ratios were used to estimate plasma equivalent concentrations, and paired VAMS and plasma samples from ten breast cancer patients showed strong correlations and good agreement on Bland-Altman analysis, supporting reliable decentralised TDM.

Development and validation of an LC-MS/MS method for the comprehensive quantification of tamoxifen and its metabolites in volumetric absorptive microsampling: clinical application in breast cancer patients — Kuo et al., Analytical and bioanalytical chemistry (paywalled) · source ↗

• blood
• dried
• vams
• neoteryx-mitra
• validation
• venous-agreement
• tdm
• oncology

This study employed volumetric absorptive microsampling to collect blood samples from neonates, revealing that existing propofol pharmacokinetic models poorly predicted drug levels in this population. A newly developed meta-model provided accurate predictions, validating the use of patient-centric microsampling for therapeutic drug monitoring in preterm and term infants.

Systematic evaluation of propofol population pharmacokinetic models and development of a literature-supported new meta-model for critically ill preterm and term neonates — Rantanen et al., European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences (paywalled) · source ↗

• blood
• dried
• vams
• neoteryx-mitra
• validation
• pediatric
• tdm