Evaluation of dried blood spot technique for pharmacokinetic study of hydrochlorothiazide and comparison of human plasma versus dried blood spot

Abstract

Background:The dried blood spot (DBS) technique is a convenient alternative sample collection method to venipuncture. The use of DBS was first widely introduced in the 1960’s by Dr Guthrie to measure levels of phenylalanine in newborns for the diagnosis of phenylketonuria. The scientific community has recently expressed interest in applying the DBS technique for quantification of drugs in biological fluids. Methods:Reversed phase high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) assays for the determination of hydrochlorothiazide in human plasma and DBS samples were developed and validated. Furthermore, clinical samples collected from human volunteers as a part of pharmacokinetic study and PK data from plasma were compared against DBS. Results:The range of reliable response in plasma and DBS was 2–200 ng/mL with correlation coefficient ≥ 0.997. Inter-day accuracy was always within 85–115% and inter-day precision for plasma and DBS were less than15%. Conclusions:Comparison of hydrochlorothiazide PK data in DBS and plasma yielded good correlation, indicating that DBS can be used as a plasma alternative for pharmacokinetic analyses in vivo. Key words: Dried blood spot; pharmacokinetic; validation; hydrochlorothiazide.