The analysis of DBS for the determination of drug concentrations in whole blood is well known.^1,2 However, very little work has been done to apply this technique on fluids other than whole blood. Traditional analyses on other fluids, such as synovial fluid, have been cumbersome due to the limitation on sample volume. Other fluids, such as urine, often require freezing a large volume sample after collection.

DBS techniques have provided an alternative method to traditional forms of analysis of low volume assays, methods that require a large volume of sample collection/storage, or complex storage conditions not readily available at some sample collection sites.

Here we report on a simple DBS preparation method coupled with HPLC/MS/MS to provide an accurate and precise assay for the determination of Indomethacin from human urine, human saliva, and mini-pig synovial fluid.