The analysis of dry blood spots (DBS) for the determination of drug concentrations in whole blood is well known.1,2 Recently, novel methods for visual indication of clear fluids (e.g. synovial fluid and CSF) on the collection paper using the DBS technique have been developed.3 This novel technique is called dried matrix spot (DMS) analysis.
The desire of researchers to obtain distribution data from multiple compartments continues to expand the application of DMS to other fluids such as tears and dialysate. Additionally, research has suggested that using other compartments such as tears can be an alternative for therapeutic drug monitoring.4 However, the collection of tears can be problematic due to the limited volume of the fluid and difficulty with sampling into a tube or vessel.
Dried matrix spot analysis offers an attractive alternative to the collection and analysis of tears and other clear fluids. As an example for analysis of clear fluids, here we report on a novel DMS preparation method coupled with LC/MS/MS to provide an accurate and precise assay for the determination of Tobramycin from human tears.
