Multiplex Analysis of 230 Medications and 30 Illicit Compounds in Dried Blood Spots and Urine

An LC-MS/MS Method for Quantification of Lamotrigine and Its Main Metabolite in Dried Blood Spots

BACKGROUND

The antiepileptic drug lamotrigine (LTG) shows high pharmacokinetic variability due to genotype influence and concomitant use of glucuronidation inducers and inhibitors, both of which may be frequently taken by elderly patients. Our goal was to develop a reliable quantification method for lamotrigine and its main glucuronide metabolite lamotrigine-N2-glucuronide (LTG-N2-GLU) in dried blood spots (DBS) to enable routine therapeutic drug monitoring and to identify altered metabolic activity for early detection of drug interactions possibly leading to suboptimal drug response.

RESULTS

The analytical method was validated in terms of selectivity, accuracy, precision, matrix effects, haematocrit, blood spot volume influence, and stability. It was applied to a clinical study, and the DBS results were compared to the concentrations determined in plasma samples. A good correlation was established for both analytes in DBS and plasma samples, taking into account the haematocrit and blood cell-to-plasma partition coefficients. It was demonstrated that the method is suitable for the determination of the metabolite-to-parent ratio to reveal the metabolic status of individual patients.

CONCLUSIONS

The clinical validation performed confirmed that the DBS technique is a reliable alternative for plasma lamotrigine and its glucuronide determination.

A new approach with dried plasma spots: a rapid determination of antidepressants and antipsychotics by fast GC-MS

Background: The increasing prevalence of poisoning cases related to antidepressants and antipsychotics has raised concerns. Methods: To address this issue, a new adaptation of the dried plasma spot technique was developed using a 24-well plate and fast gas chromatography-mass spectrometry. The method involves the optimization of extraction variables and sample preparation, and was successfully validated. Results: The limits of quantitation ranged from 20 to 60 ng/ml, and accuracy ranged from 87.8% to 112.2%. The technique was applied to 102 human plasma samples from suspected poisoning cases, with positivity of 90.2%. Conclusion: This method provides a cheap, easy to implement and fast approach, making it ideal for toxicological emergency laboratories and promoting valuable support for healthcare professionals managing poisoning cases involving antidepressants and antipsychotics.

Effects of Pharmacogenomic Testing in Clinical Pain Management: Retrospective Study

BACKGROUND

The availability of pharmacogenomic (PGx) methods to determine the right drug and dosage for individualized patient treatment has increased over the past decade. Adoption of the resulting PGx reports in a clinical setting and monitoring of clinical outcomes is a challenging and long-term commitment.

OBJECTIVE

This study summarizes an extended PGx deep sequencing panel intended for medication dosing and prescription guidance newly adopted in a pain management clinic. The primary outcome of this retrospective study reports the number of cases and types of drugs covered, for which PGx data appears to have assisted in optimal drug prescription and dosing.

METHODS

A PGx panel is described, encompassing 23 genes and 141 single-nucleotide polymorphisms or indels, combined with PGx dosing guidance and drug-gene interaction (DGI) and drug-drug interaction (DDI) reporting to prevent adverse drug reactions (ADRs). During a 2-year period, patients (N=171) were monitored in a pain management clinic. Urine toxicology, PGx reports, and progress notes were studied retrospectively for changes in prescription regimens before and after the PGx report was made available to the provider. An additional algorithm provided DGIs and DDIs to prevent ADRs.

RESULTS

Among patient PGx reports with medication lists provided (n=146), 57.5% (n=84) showed one or more moderate and 5.5% (n=8) at least one serious PGx interaction. A total of 96 (65.8%) patients showed at least one moderate and 15.1% (n=22) one or more serious DGIs or DDIs. A significant number of active changes in prescriptions based on the 102 PGx/DGI/DDI report results provided was observed for 85 (83.3%) patients for which a specific drug was either discontinued or switched within the defined drug classes of the report, or a new drug was added.

CONCLUSIONS

Preventative action was observed for all serious interactions, and only moderate interactions were tolerated for the lack of other alternatives. This study demonstrates the application of an extended PGx panel combined with a customized informational report to prevent ADRs and improve patient care.

Dried matrix spots in forensic toxicology

Dried matrix spots (DMS) has gained the attention of different professionals in different fields, including toxicology. Investigations have been carried out in order to assess the potential of using DMS for the analysis of illicit substances, the main interest of forensic toxicologists. This technique uses minimal volumes of samples and solvents, resulting in simple and rapid extraction procedures. Furthermore, it has proved to increase analyte stability, improving storage and transportation. However, DMS presents some limitations: the hematocrit influencing accuracy and inconsistencies regarding the means of spotting samples and adding internal standard on paper. Thus, we provide an overview of analytical methodologies with forensic applications focusing on drugs of abuse and discussing the main particularities, limitations and achievements.