Evaluation of glucuronide metabolite stability in dried blood spots.

Stabilization of phase II metabolites is an important consideration during bioanalytical method development, method validation and sample analysis. Generic approaches to stabilize these metabolites during storage in liquid-based matrices include pH adjustment of samples prior to storage and/or temperature control; although a variety of other compound-specific stabilization techniques exist. Dried blood spot (DBS) technology is becoming a popular alternative to liquid matrix sampling in many preclinical and clinical applications. However, concerns remain regarding the stability of metabolites stored under ambient conditions using DBS. Experimental data have shown that, under ambient storage conditions, the stability of the glucuronides investigated herein stored as DBS is equivalent to that of liquid samples stored at -80°C. The decision to employ DBS technology for a given study needs to be considered on a case-by-case basis with an understanding of compound-specific metabolism characteristics and clinical study design.