2021 · Advances in pharmacological and pharmaceutical sciences · open access
Development and Validation of the Quantification Method for Hydroxychloroquine in Volumetric Absorptive Microsampling (VAMS) Using High-Performance Liquid Chromatography-Photodiode Array
Harahap et al.
The finding, in our words
The authors validated a VAMS method for hydroxychloroquine that meets FDA bioanalytical standards, achieving a lower limit of quantification of 2 ng/mL. This supports decentralised therapeutic drug monitoring for patients on long-term therapy, enabling microsampling at home rather than venous draws in clinics.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
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.
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.
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.
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.
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.