Learning how to interpret 'dangerous' internal standard behaviors.

Internal standard (IS) response has been an active topic of discussion within the bioanalytical community. Initial discussions focused on developing criteria for anomalous responses. Recently, understanding the cause and potential impact of variable IS response has been emphasized. Following a review of recommendations from industry discussions regarding variable IS responses, case studies where interferences with IS response resulted in quantitation inaccuracy are presented. The examples illustrate that variable IS response cannot always be attributed to compensation of matrix effects. Anomalous IS responses, even for stable label internal standards should be investigated and the root cause for the anomalous behavior should, if possible, be determined.

Perspectives on the draft ICH-M10 guidance: an interview with Eric J Woolf.

Biography Dr Woolf is currently Executive Director of the regulated PK Bioanalysis Group of Merck Research Laboratories, West Point, PA, USA. He received his BA in Chemistry from LaSalle College in 1982, and a PhD in Analytical Chemistry from Seton Hall University in 1986. From 1986 to 1990, he was a member of the Drug Metabolism/Pharmacokinetics Department of Berlex Laboratories. He joined Merck Research Laboratories in 1990 as a research fellow. Dr Woolf and his group have supported numerous clinical development projects that have led to the successful registration of Merck compounds. Since 1986, he has authored or coauthored over 50 research papers pertaining to bioanalysis and pharmacokinetics. This interview was conducted by Sankeetha Nadarajah, Managing Commissioning Editor of Bioanalysis, at the AAPS ICH-M10 Public Consultation Workshop (Silver Spring, MD, USA), 11 June 2019.