Feedback from a European Bioanalysis Forum survey on bioanalysis of drugs in tissues.

Tissue analysis has always been a difficult discipline of bioanalysis. Laboratories that perform bioanalysis in tissue are facing a lot of challenges and questions before starting experiments, from a scientific/technical point of view regarding more regulated aspects. Actually, literature is poor regarding the more technical and scientific aspects but also beyond that no clear guidance is available on this topic and laboratories performing tissue analysis face real ambiguity regarding regulatory requirements, always with the risk of under- or over-validation of the assay. For all of these reasons bioanalysis in tissue became a frequently discussed topic within the European Bioanalytical Forum (EBF) organization. The EBF then decided to treat this as a specific topic, and carried out a survey that was done in two steps between 2012 and 2013. This paper represents an exhaustive summary of the result of this survey that includes themost important aspects of tissue bioanalysis. This survey provided the team a good starting point for their discussions and resulted in an EBF recommendation paper published separately.

Recommendations from the European Bioanalysis Forum on method establishment for tissue homogenates.

Tissue analysis has always been a difficult discipline of bioanalysis. Differences in scientific approaches or level of adherence to regulated guidelines have led to a growing ambiguity on how to perform tissue analysis, an ambiguity that starts with the question of if we analyze tissue or tissue homogenates. The European Bioanalysis Forum (EBF) is proposing a recommendation on how to perform method establishment and analysis of tissue homogenates. The recommendation is based on broad discussions and survey data from the EBF community and, as for many EBF recommendations, focuses on finding the right balance between science, technology and regulations.

Validation of an LC-MS bioanalytical method for quantification of phytate levels in rat, dog and human plasma.

Myo-inositol hexakisphosphate (phytate, IP6) is a naturally occuring compound whose determination in biological matrices is chanllenging. Several benefitial properties have been attributed to IP6 in parallel with the development of suitable analytical methodologies for its analytical determination in urine and some tissues. However, there is a lack of appropriate tools for its determination in plasma samples. In this paper, a direct, sensitive and selective bioanalytical method for the determination of IP6 based on LC-MS is presented. It is the first method published to quantify IP6 in plasma matrices directly through its molecular weight, being consequently a highly specific methodology. The method has been validated in rat, dog and human plasma, according to the acceptance criteria laid down in the FDA guidance Bioanalytical Method Validation. Accuracy and precision were not greater than 15% at medium and high concentrations and not greater than 20% at the LLOQ concentration. The mean absolute recovery obtained ranged from 78.74 to 102.44%, 62.10 to 87.21% and 61.61 to 86.99% for rat, dog and human plasma respectively. The LLOQ was 500ngmL(-1) due to the presence of endogenous IP6 in blank plasma samples and the limit of detection was within the range 30-80ngmL(-1).