Opportunities and obstacles for microsampling techniques in bioanalysis: Special focus on DBS and VAMS.

Microsampling, a reduced volume (< 50 μl) sampling method has successfully gained attention at the International Conference on Harmonization (ICH) level. It has been reflected in a few guidelines like ICH SA3, S11 and M10. The established benefits of microsampling support its use in Toxicokinetic (TK) and Pharmacokinetic (PK) studies, clinical studies, neonate sampling and remote sampling. When designing the TK component of a juvenile animal study, microsampling and sparse sampling (if justified) are strongly encouraged from the view of 3Rs (Replace, Refine, and Reduce). The novel sampling techniques arose with benefits over conventional sampling in terms of ease of sampling, storage, and shipment. These improved sampling techniques are less invasive and preferred by patients and trial participants. For the acceptance of these techniques in regulated bioanalysis, it is essential to prove its suitability with a robust and reliable method. Though there are many opportunities for the newer and smarter microsampling devices, the major obstacles are hematocrit influence, homogeneity of samples, repeats, incurred samples reanalysis and regulatory acceptance. With the advancement in techniques, opportunities are marching ahead of obstacles. The two microsampling techniques Dried Blood Spot (DBS) and Volumetric Absorption Microsampling (VAMS) are studied and elaborated in this article with respect to bioanalytical consideration, method validation and regulatory perspectives on its acceptance in regulated bioanalysis.