Abstracts

Rationale: Therapeutic Drug Management (TDM) of anticonvulsants is an important tool in the management of patients with seizure disorders. A high performance liquid chromatography method utilizing tandem mass spectrometry detection (LCMSMS) allows the simultaneous measurement of mutiple anticonvulsants in capillary blood spots collected onto filter paper. The use of the filter paper collection technique provides a means not only for healthcare providers to collect TDM samples in routine situations, but also for non-medical caregivers to collect samples at crucial time-points when phlebotomy may not be readily accessible. A correlation study was performed to evaluate the feasibility of this alternative collection and testing paradigm. Methods: Subjects enrolled in the study adhere to the monitoring schedule prescribed by treating physicians. Venipuncture samples are collected according to the customary protocol. A lancet is then used to pierce the fingertip and 2 drops of capillary blood (approximately 120 μL) are collected onto a filter paper blood collection device. Specimens are transported to the laboratory for testing. Plasma samples are tested using the current validated methodologies routinely used for the clinic samples; this sample is the predicate sample/method for comparison purposes. Filter paper specimens are processed for testing by punching circles from the filter paper and placing them into test tubes. Internal standards are added and the analytes are solubilized into a mixture of acetonitrile and water. Quantitative standards and controls are processed in the same manner. Processed samples, standards and controls are analyzed by LCMSMS. Results: Results are presented in Table 1. Conclusions: The data demonstrate excellent correlation of anticonvulsant concentrations in plasma and capillary whole blood collected on filter paper for six anticonvulsant compounds. Additional sample collections are ongoing to evaluate three additional drugs. Most remaining anticonvulsants compounds can be tested by the system, but correlation data is lacking due to low prevalence of use in this adult study population. The capillary blood fiter paper collection was well received by study participants. We conclude that this filter paper collection and testing paradigm provides a means by which meaningful drug concentration data can be obtained in both medical and home settings.