LC-MS-MS Determination of Cytostatic Drugs on Surfaces and in Urine to Assess Occupational Exposure.

The ever-increased usage of cytostatic drugs leads to high risk of exposure among healthcare workers. Moreover, workers are exposed to multiple compounds throughout their lives, leading to cumulative and chronic exposure. Therefore, multianalyte methods are the most suitable for exposure assessment, which minimizes the risks from handling cytostatic drugs and ensures adequate contamination containment. This study describes the development and full validation of two liquid chromatography-tandem mass spectrometry methods for the detection of gemcitabine, dacarbazine, methotrexate, irinotecan, cyclophosphamide, doxorubicinol, doxorubicin, epirubicin, etoposide, vinorelbine, docetaxel and paclitaxel in working surfaces and urine samples. The urine method is the first to measure vinorelbine and doxorubicinol. For surfaces, limits of detection (LOD) and limits of quantification (LOQ) were 5-100 pg/cm2, and linearity was achieved up to 500 pg/cm2. Inaccuracy was between -11.0 and 8.4%. Intra-day, inter-day and total imprecision were <20%, except for etoposide and irinotecan (<22.1%). In urine, LOD and LOQ were 5-250 pg/mL, with a linear range up to 1,000-5,000 pg/mL. Inaccuracy was between -3.8 and 14.9%. Imprecision was <12.4%. Matrix effect was from -58.3 to 1,268.9% and from -66.7 to 1,636% in surface and urine samples, respectively, and extraction efficiency from 10.8 to 75% and 47.1 to 130.4%, respectively. All the analytes showed autosampler (6°C/72 h), freezer (-22°C/2 months) and freeze/thaw (three cycles) stability. The feasibility of the methods was demonstrated by analyzing real working surfaces and patients' urine samples. Contamination with gemcitabine, irinotecan, cyclophosphamide, epirubicin and paclitaxel (5-4,641.9 pg/cm2) was found on biological safety cabinets and outpatients' bathrooms. Analysis of urine from patients under chemotherapy identified the infused drugs at concentrations higher than the upper LOQ. These validated methods will allow a comprehensive evaluation of both environmental and biological contamination in hospital settings and healthcare workers.

Comparison of conventional dried blood spots and volumetric absorptive microsampling for tacrolimus and mycophenolic acid determination.

Therapeutic drug monitoring (TDM) of immunosuppressants is essential to avoid either rejection or toxicity after solid organ transplantations. Capillary microsampling approaches are an outstanding alternative to conventional venous sampling for TDM (easy and non-invasive collection, enabling self-sampling, and cost-saving shipment, processing and storage). Volumetric absorptive microsampling (VAMS) has gained importance in the last years, as it was meant to overcome the hematocrit (Hct) related issues commonly associated to DBS analysis. Despite all the benefits, microsampling techniques performance (including a thorough clinical validation) should be set up before their implementation in clinical practice. The aim of this study was to perform a clinical validation for both tacrolimus (TAC) and mycophenolic acid (MPA) in both DBS and Mitra™ VAMS. For the clinical validations, two different requirements were set up: analytical (following EMA and FDA guidelines) and clinical (following the Royal College of Pathologists of Australasia -RCPA- recommendations) acceptance criteria. For DBS, both analytical and clinical acceptance criteria were fulfilled for TAC, with 98.7% and 95% of the paired samples within the preset limits, respectively. For MPA, the analytical criterion was met (70.6% of paired specimens), although only half of the pairs were within the clinical limits. For VAMS, the clinical validation for both TAC and MPA showed good correlations but significant lower concentrations in VAMS compared to the routine matrices. After VAMS concentrations correction, the analytical requirement was fulfilled for both analytes (71.1% for TAC, 75% for MPA), although the more restrictive criteria recommended by the RCPA were not met for any analyte (half of the samples fell within the acceptance area). In addition, no significant Hct impact on the quantification was found in any case. Also, a preliminary home-sampling trial was set up, showing promising results. Moreover, a comparison between VAMS vs. DBS analytical and clinical performances was carried out, including a home-sampling trial, sample quality results and costs. Although the analytical performance for both VAMS and DBS was similar, DBS were superior regarding clinical criteria, sampling quality and cost.

Volumetric Absorptive Microsampling (VAMS) for assaying immunosuppressants from venous whole blood by LC-MS/MS using a novel atmospheric pressure ionization probe (UniSpray™).

Therapeutic drug monitoring (TDM) of immunosuppressants (IMS) is crucial to prevent rejection or toxicity after solid organ transplantation. Microsampling techniques (sampling <50 µL of blood) can be a good alternative to conventional venous sampling for TDM, due to their numerous advantages, including its easy and low-invasive sampling, enabling self-collection, and cost-saving shipment and storage. Furthermore, volumetric absorptive microsampling (VAMS) enables the collection of precise and accurate blood volumes, overcoming the hematocrit (Hct) effect related to dried blood spots, while offering the same benefits. In this work, an LC-MS/MS method for the determination of the 5 most common IMS (mycophenolic acid -MPA-, tacrolimus -TAC-, sirolimus -SIR-, everolimus -EVE- and cyclosporin A -CsA-) in venous blood collected with Mitra™ VAMS devices was developed and validated, employing a novel LC-MS/MS interface, Unispray™. The method was fully validated including linearity, limits of detection (LOD) and quantification (LLOQ), accuracy, precision, selectivity, carry-over, matrix effect, recovery, impact of Hct on recovery and autosampler and short-/long-term stability, satisfying acceptance criteria in all cases. LLOQs were 0.5 ng/mL for TAC, SIR and EVE, 20 ng/mL for CsA and 75 ng/mL for MPA. No impact of the Hct (range: 0.2 to 0.62 L/L) on recovery was found for any analyte. All compounds were stable in VAMS for at least 8 months at -20 °C. In addition, as part of the VAMS analytical method validation, we performed for the first time a broad statistical study to compare liquid venous blood concentrations from patients under TAC (n = 53) and MPA (n = 20) treatment to those observed when the same specimens were absorbed into VAMS. Our results showed that venous blood VAMS concentrations were correlated to those found in the original liquid venous blood, proving that the VAMS material itself will not bias blood drug concentrations. Therefore, the present method could be applied to evaluate possible correlations between venous blood and capillary blood collected with VAMS.

Evaluation of the Performance and Hematocrit Independence of the HemaPEN as a Volumetric Dried Blood Spot Collection Device.

Dried blood spots (DBS) are often used as a less invasive alternative to venous blood sampling. Despite its numerous advantages, the use of conventional DBS suffers from the hematocrit (hct) effect when analyzing a subpunch. This effect could be avoided by using hct-independent sampling devices, of which the hemaPEN is a recent example. This device collects the blood via four integrated 2.74 µL microcapillaries, each depositing the blood on a prepunched paper disc. In this study, we evaluated the technical performance of the hemaPEN devices, using an extensive bioanalytical validation and application on authentic patient samples. An LC-MS/MS method quantifying caffeine and its metabolite paraxanthine in dried whole blood (using the hemaPEN device) was fully validated, meeting all preset acceptance criteria. A comparative analysis of 91 authentic patient samples (hct range: 0.17-0.53) of hemaPEN, 3 mm DBS subpunches, and whole blood revealed a limited hct dependence (≤7% concentration difference over a 0.20-0.50 hct range) for the hemaPEN devices, which we could not attribute to the analytical procedure. Using conventional partial-punch DBS (3 mm punches), concentration differences of ≥25% over this hct range were found. The hemaPEN showed to be robust to the effects of blood sample volume, device lot, analytical operator, and storage stability. The technical performance of the hemaPEN when dealing with patients having a high hct and in cases where a large blood drop is present should be further investigated. Based on the successful validation and application on patient samples, we conclude that the hemaPEN device shows good potential for the volumetric collection of DBS.

A multidrug LC-MS/MS method for the determination of five immunosuppressants in oral fluid.

Aim: This study aimed: to develop and validate an LC-MS/MS method for mycophenolic acid, tacrolimus, sirolimus, everolimus and cyclosporin A in oral fluid (OF), as an essential tool to study the usefulness of OF as an alternative matrix for immunossuppressants' therapeutic drug monitoring; and to find the best OF collector for these analytes. Materials & Methods: Chromatographic separation was achieved using an XBridge® Shield RP18 analytical column maintained at 65ºC, using 2 mM ammonium formate and 0.1% formic acid in water (A) and acetonitrile (B) as mobile phase. OF sample was extracted with solid phase extraction after sonication and protein precipitation. Results & Conclusions: Method validation met all the acceptance criteria. LODs were 0.05-1 ng/ml, and LOQs 0.1-5 ng/ml. Silanized tubes offered the best recoveries. The method was successfully applied to 31 OF specimens, describing everolimus detection in OF for the first time. Conclusion: The proposed method is sensitive enough for the detection of OF trough concentrations in patients receiving immunosuppressants when using an appropriate OF collector.

Development and validation of a liquid chromatography-tandem mass spectrometry method for the determination of nicotine and its metabolites in placenta and umbilical cord.

Tobacco exposure during pregnancy is associated with obstetric and fetal complications. We developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine nicotine, cotinine, and hydroxycotinine (OH-cotinine) in placenta (PL) and umbilical cord (UC). Specimens were homogenized in water, followed by solid-phase extraction. Chromatographic separation was performed using an Atlantis® HILIC Silica column. Detection was accomplished in electrospray in positive mode. Method validation included: linearity (5 to 1000 ng/g), accuracy (86.9 to 105.2% of target concentration in PL, and 89.1 to 105.0% in UC), imprecision (6.8 to 11.8% in PL, and 7.6 to 12.2% in UC), limits of detection (2 ng/g for cotinine and OH-cotinine, and 5 ng/g for nicotine) and quantification (5 ng/g), selectivity (no endogenous or exogenous interferences), matrix effect (-34.1 to -84.5% in PL, %CV = 9.1-24.0%; -18.9 to -84.7% in UC, %CV = 10.2-23.9%), extraction efficiency (60.7 to 131.5% in PL, and 64.1 to 134.2% in UC), and stability 72 h in the autosampler (<11.5% loss in PL, and < 13% loss in UC). The method was applied to 14 PL and UC specimens from tobacco users during pregnancy. Cotinine (6.8-312.2 ng/g in PL; 6.7-342.3 ng/g in UC) was the predominant analyte, followed by OH-cotinine (