Impact of introducing a new biological matrix into a validated bioanalytical method: Focus on matrix protein content

International guidance on bioanalytical method validation recommends the practice of partial validation when introducing a new matrix from the same species into a previously fully validated assay. Planning the partial validation protocol should include an evaluation of analyte chemistry, consideration of sample container materials, and a comparison of properties between the relevant biological matrices. Transition of a serum/plasma-validated bioanalytical method to analysis from a low-protein matrix, such as urine, cerebral spinal fluid, or oral fluid can result in inconsistent analyte recovery. The low recovery can potentially be mistaken for signal suppression or lack of drug stability and may be more pronounced in low-concentration or low-volume samples. In addition, adsorption and absorption interactions with containers may be exacerbated in low-protein matrices. Several possibilities exist for mitigating the impact of non-specific binding and low-protein matrices, including surfactants, bovine serum albumin, and β-cyclodextrin. Finally, higher matrix protein can facilitate analyte stability. Given all this, matrix protein content should not be overlooked when anticipating a partial bioanalytical method validation.

A fully validated method for simultaneous determination of icotinib, osimertinib, gefitinib and O-desmethyl gefitinib in human plasma using UPLC-MS/MS for therapeutic drug monitoring

BACKGROUND AND AIMS

A few researches have reported the exposure-efficacy/toxicity relationships of epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs). On account of the large interpatient pharmacokinetic variability, therapeutic drug monitoring (TDM) seems promising for optimizing dosage regimen and improving treatment efficacy and safety. Therefore, a rapid and convenient ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of icotinib, osimertinib, gefitinib and O-demesthyl gefitinib in human plasma for TDM.

MATERIALS AND METHODS

Icotinib-D4 and osimertinib-13CD3 were used as the internal standards (ISs). The samples were prepared by protein precipitation using acetonitrile. Chromatographic separation was achieved on a 40 ℃ Shimadzu Shim-pack Scepter C18-120 column (2.1 ×50 mm, 3.0 µm, Japan) by a Shimadzu 30 A solvent management system. Detection was carried out using a Shimadzu LC-MS 8050CL triple quadrupole mass spectrometer coupled with an electrospray ionization source in positive mode.

RESULTS

This analytical method was fully validated with selectivity, carry-over, linearity, lower limit of quantification, accuracy (from 92.68% to 106.62%) and precision (intra- and inter-day coefficients of variation ranged from 0.92% to 9.85%), matrix effect, extraction recovery, stability and dilution integrity. The calibration curves were developed to be within the concentration ranges of 200-4000 ng/mL for icotinib, 50-1000 ng/mL for osimertinib, gefitinib and O-desmethyl gefitinib in human plasma which meet the needs of routine TDM.

CONCLUSIONS

The proposed method was used in 100 patients with non-small cell lung cancer for monitoring plasma concentration of the mentioned EGFR-TKIs. The trough concentrations of ICO were distributed between 226.42 ng/mL and 3853.36 ng/mL, peak concentrations were between 609.20 ng/mL and 2191.54 ng/mL. The trough concentrations of OSI were distributed between 110.48 ng/mL and 1183.13 ng/mL. The trough concentrations of GEF were distributed between 117.71 ng/mL and 582.74 ng/mL, while DeGEF was distributed from 76.21 ng/mL to 1939.83 ng/mL with two less than 20 ng/mL. The results of therapeutic drug monitoring aimed to investigate exposure-efficacy/toxicity relationship and improve the efficacy and safety of targeted therapies.

An LC-ESI-MS/MS method for determination of ondansetron in low-volume plasma and cerebrospinal fluid: Method development, validation, and clinical application

Ondansetron is used in clinical settings as an antiemetic drug. Although the animal studies showed its potential effectiveness also in treating neuropathic pain, the results from humans are inconclusive. The lack of efficacy of ondansetron in a subset of patients might be due to the overexpression of P-glycoprotein, which could result in low concentrations of ondansetron in the central nervous system (CNS). A surrogate of the CNS exposure might be drug concentration in the cerebrospinal fluid (CSF), especially in humans, as assessing the drug disposition directly in the patient's brain would be challenging. The study aimed to develop a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine concentrations of ondansetron in human K3EDTA plasma and CSF. Ondansetron was extracted from biological matrices by liquid-liquid extraction. The quantification was performed on a Sciex QTRAP 6500+ mass spectrometer with labeled ondansetron as an internal standard. The calibration range was 0.25-350 ng/mL in plasma and 0.025-100 ng/mL in CSF; for both matrices, 25 µL of samples was required for the assays. The method was validated according to the FDA and EMA guidelines and showed acceptable results. A pilot study confirmed its suitability for clinical samples: after 4-16 mg of intravenous ondansetron, the determined concentrations in plasma were 1.22-235.90 ng/mL, while in CSF - 0.018-11.93 ng/mL. In conclusion, the developed method fulfilled all validation requirements and can be applied to pharmacokinetic studies assessing the CNS ondansetron exposure in humans. The method's advantages, such as a low volume of matrix and a wide calibration range, support its use in a study in which rich sampling and various drug doses are expected.

Rapid extraction of osimertinib and its active metabolite in urine by miniaturized centrifugal spin-column extraction using ionic liquid hybrid hierarchical porous adsorbent

Osimertinib (OSIM) is widely used as a mainstream drug for the treatment of non-small cell lung cancer (NSCLC). However, the lack of a rapid extraction and detection method for OSIM and its metabolite, AZ-5104, has limited clinical drug metabolism and drug resistance research because the drug is unstable. In this study, a new ionic liquid hybrid hierarchical porous material (IL-HHPM) was synthesized with hierarchical porous structures, including micropores (1.6-2.0 nm), mesopores (2.0-50.0 nm), macropores (50.0-148.7 nm), and multiple functional groups via a one-step hydrothermal method using silanized ionic liquids (IL) as functionalized hybrid monomer. The IL-HHPM has the advantages of a high specific surface area (437.4 ± 4.6 m2 g-1), sizable pore volume (0.74 cm3 g-1), and fast mass transfer, additionally, the IL-HHPM adsorbed OSIM and AZ-5104 via π-π interactions and hydrogen bonding. OSIM and AZ-5104 were rapidly extracted and measured in human urine using rapid and miniaturized centrifugal spin-column extraction (MCSCE), which was based on the IL-HHPM. The optimized factors for the extraction recoveries of OSIM and AZ-5104 were adsorbent dosage (8.0 mg), sample volume (0.5 mL), and operation time (9.0 min), and markedly reduced the adsorbent dosage and operation time. The IL-HHPM-MCSCE-HPLC method displayed good linearity (0.02-5.00 μg mL-1, r ≥ 0.9997), satisfying accuracy (spiked recoveries of 87.7%-100.0%), and good precision (RSDs ≤ 7.0%). The developed method is rapid, sensitive, and reproducible for the simultaneous determination of trace level of OSIM and AZ-5104 in human urine.

Determining plasma and cerebrospinal fluid concentrations of EGFR-TKI in lung cancer patients

Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are commonly used to treat advanced non-small cell lung cancer (NSCLC). A rapid and reliable method for measuring plasma and cerebrospinal fluid (CSF) concentrations of EGFR-TKIs is needed for therapeutic drug monitoring. By using UHPLC‒MS/MS with multiple reaction monitoring mode, we developed a method for rapidly determining the plasma and CSF concentrations of gefitinib, erlotinib, afatinib, and osimertinib. Protein precipitation was employed to remove protein interference for plasma and CSF matrix. The LC‒MS/MS assay was validated to be satisfactory in terms of linearity, precision, and accuracy. This method was successfully applied to measure plasma (n = 44) and CSF (n = 6) concentrations of EGFR-TKIs in NSCLC patients. The chromatographic separation was achieved by a Hypersil Gold aQ column within 3 minutes. The median plasma concentrations were 325.76, 1981.50, 42.62, 40.27, and 340.92 ng/ml for gefitinib erlotinib, afatinib 30 mg/day, afatinib 40 mg/day, and osimertinib, respectively. The CSF penetration rates were 2.15% for the patients receiving erlotinib therapy, 0.59% for afatinib, 0.08-1.12% for osimertinib 80 mg/day, and 2.18% for those receiving osimertinib 160 mg/day. This assay helps to predict the effectiveness and toxicities of EGFR-TKIs in the pursuit of precision medicine for lung cancer patients.

Quantitation of osimertinib, alectinib and lorlatinib in human cerebrospinal fluid by UPLC-MS/MS

Overall survival in metastatic lung cancer has been dramatically improved with the use of small molecule kinase inhibitors (SMKIs). Quantification of SMKI in cerebrospinal fluid (CSF) can be used to assess penetration of these drugs into the central nervous system. This paper describes an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for quantification of the SMKIs alectinib, lorlatinib and osimertinib in human CSF. Alectinib-d8 and dasatinib-d8 were used as internal standards. Aliquots with 25 µL CSF/30% albumin (9:1,v/v) were mixed with 100 µL internal standard solution consisting of 1 ng/mL dasatinib-d8 and alectinib-d8 in acetonitrile. The analytes were separated by an Acquity UPLC® HSS T3 column (2.1 ×150 mm, 1.8 µm), using gradient elution (ammonium formate pH 4.5, acetonitrile) with a flow rate of 0.400 mL/min. All calibration curves were linear for the concentration range from 2.50 to 250 ng/mL. Within-run and between-run precision varied from 0.72% to 11.7%, with accuracy ranging from 95.3% to 113.2%. For all compounds, a high degree of non-specific binding to the vacutainer was observed. This issue could be countered easily by a combination of pre-coating with BSA solution (30%) in phosphate buffer pH 4.2, and immediate sample mixture with BSA solution after collection. To test the clinical applicability, CSF was collected in seven unique patients using alectinib (n = 1), lorlatinib (n = 2), and osimertinib (n = 4). Measured CSF trough concentrations ranged between 3.37 and 116 ng/mL.

Instability Mechanism of Osimertinib in Plasma and a Solving Strategy in the Pharmacokinetics Study

Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) and a star medication used to treat non-small-cell lung carcinomas (NSCLCs). It has caused broad public concern that osimertinib has relatively low stability in plasma. We explored why osimertinib and its primary metabolites AZ-5104 and AZ-7550 are unstable in rat plasma. Our results suggested that it is the main reason inducing their unstable phenomenon that the Michael addition reaction was putatively produced between the Michael acceptor of osimertinib and the cysteine in the plasma matrix. Consequently, we identified a method to stabilize osimertinib and its metabolite contents in plasma. The assay was observed to enhance the stability of osimertinib, AZ-5104, and AZ-7550 significantly. The validated method was subsequently applied to perform the pharmacokinetic study for osimertinib in rats with the newly established, elegant, and optimized ultra-performance liquid chromatography–tandem mass spectrometer (UPLC-MS/MS) strategy. The assay was assessed for accuracy, precision, matrix effects, recovery, and stability. This study can help understand the pharmacological effects of osimertinib and promote a solution for the similar problem of other Michael acceptor-contained third-generation EGFR-TKI.

Comparison of a newly developed high performance liquid chromatography method with diode array detection to a liquid chromatography tandem mass spectrometry method for the quantification of cabozantinib, dabrafenib, nilotinib and osimertinib in human serum - Application to therapeutic drug monitoring

OBJECTIVE

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a highly selective and sensitive method for the quantification of kinase inhibitors, yet not widely available in clinical routine for therapeutic drug monitoring (TDM). To provide a more accessible alternative, a high-performance liquid chromatography method with ultraviolet/diode array detection (HPLC-UV/DAD) to quantify cabozantinib, dabrafenib, nilotinib and osimertinib, was developed and validated. Results were compared to LC-MS/MS.

METHOD

After liquid-liquid-extraction and reconstitution of the residue in 20 mM potassium dihydrogen phosphate (KH2PO4) (pH4.6), acetonitrile and methanol (50:25:25,v/v/v), chromatographic separation was achieved in 20.0 min using a Luna® C18(2)-HST column (100 × 2 mm, 2.5 μm), protected by a C18 guard column (4 × 2 mm) (column temperature: 30 °C, autosampler: 10 °C). Mobile phase A and B consisted of 20 mM KH2PO4 (pH4.9) and acetonitrile (9:1,v/v) and acetonitrile:20 mM KH2PO4 (pH4.9) (7:3,v/v), respectively. Gradient elution was performed at 200 µL/min. Analytes were quantified at 250, 280 and 330 nm, using sorafenib as internal standard.

RESULTS

Calibration curves were linear (35-2,000 ng/mL). Method validation assays met requirements by U.S. Food and Drug Administration and European Medicines Agency. Compared to the more sensitive and specific LC-MS/MS, HPLC-UV/DAD showed a good correlation and a strong positive association (Kendall's tau 0.811¬-0.963, p < 0.05). Bland-Altman-plots revealed 100% (cabozantinib), 98.6% (dabrafenib), 98.6% (nilotinib) and 96.2% (osimertinib) of relative differences inside the limits of agreement. Regulatory agency criteria for sample reanalysis and cross validation were met (±20%-criterion:100% (cabozantinib), 94.3% (dabrafenib), 92% (nilotinib) and 84.6% (osimertinib).

CONCLUSION

The developed HPLC-UV/DAD method is "fit-for-TDM" in clinical routine and serves as a genuine alternative to LC-MS/MS.

Simultaneous determination of almonertinib and its active metabolite HAS-719 in human plasma by LC-MS/MS: Evaluation of pharmacokinetic interactions

The combination of two or more drugs in a clinical setting has an impact in pharmacokinetics, drug efficacy and safety, and the study of these interactions has attracted considerable attention over the last years. In the present study, we have developed a LC-MS/MS method for the sensitive and reliable quantification of almonertinib and its active metabolite HAS-719. Further, we investigated the effects of their pharmacokinetics in humans by using modulators of CYP3A, an almonertinib-metabolizing enzyme. Analytes were extracted from plasma samples via acetonitrile-induced protein precipitation and separated on a BEH C18 column using ammonium acetate with formic acid and acetonitrile as the mobile phase. Electrospray ionization in positive ion mode and multiple reaction monitoring were used to monitor the ion transitions at m/z 526 → 411 and 512 → 423. Validation was performed in the range 0.500 to 500 ng/mL for both the analytes of interest according to the guidelines of the U.S. Food and Drug Administration and European Medicines Agency, sufficient to account for variations in plasma concentrations caused by the presence of CYP3A modulators. The selectivity, precision, accuracy, recovery and matrix effect of this method were all within acceptable limits of bioanalytics. The interference of CYP3A modulators itraconazole and rifampicin with the analytes, and the mutual interference between the analytes were also investigated producing acceptable results. The method herein described was successfully applied for the pharmacokinetics evaluation of almonertinib in healthy subjects exposed to a single dose of almonertinib (110 mg), with or without itraconazole or rifampicin.

Chromatographic bioanalytical assays for targeted covalent kinase inhibitors and their metabolites

Deriving from targeted kinase inhibitors (TKIs), targeted covalent kinase inhibitors (TCKIs) are a new class of TKIs that are covalently bound to their target residue of kinase receptors. Currently, there are many new TCKIs under clinical development besides afatinib, ibrutinib, osimertinib, neratinib, acalabrutinib, dacomitinib, and zanubrutinib that are already approved by the FDA. Subsequently, there is an increasing demand for bioanalytical methods to qualitatively and quantitively investigate those compounds, leading to a number of papers reporting the development, validation, and use of bioanalytical methods for TCKIs. Most publications describe the technological set up of analytical methods that allow quantification of TCKIs in various biomatrices such as plasma, cerebrospinal fluid, urine, tissue, and liver microsomes. In addition, the identification of metabolites and biotransformation pathways of new TCKIs has gained more interest in recent years. We provide an overview of bioanalytical methods of this new class of TCKIs. The included issues are sample pretreatment, chromatographic separation, detection, and method validation. In the scope of bioanalysis of TCKIs, protein precipitation is mostly applied to treat the biological matrices sample. Liquid chromatographic in reversed-phase mode (RPLC) and mass detection with triple quadrupole (QqQ) are the most often utilized separation and quantitative detection modes, respectively. There may be a possibility of increased use of the high-resolution mass spectrometry (HRMS) for qualitative investigation purposes in the future. We also found that US FDA and EMA guidelines are the most common guidelines employed as validation framework for the bioanalytical methods of TCKIs.

Rapid and Sensitive Quantification of Osimertinib in Human Plasma Using a Fully Validated MALDI-IM-MS/MS Assay

The third-generation tyrosine kinase inhibitor (TKI), osimertinib, has revolutionized the treatment of patients with non-small cell lung carcinoma with epidermal growth factor receptor (EGFR)-activating mutation, and resistant to first- and second-generation TKIs. Osimertinib is now also proposed as a first-line therapy, thus extending the scope of applications in lung oncology. Personalized medicine approaches are still necessary to monitor if patients are exposed to adequate concentrations of osimertinib during their treatment. It would also help to understand the appearance of new resistances in patients after several months of dosing with osimertinib. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) is currently the gold standard for the quantification of drugs in plasma enabling pharmacokinetic analyses and patient monitoring. In the present study, we propose an alternative to LC–MS/MS methods for the rapid and sensitive quantification of osimertinib in plasma using matrix-assisted laser desorption/ionization (MALDI) –MS. The presented assay requires only 3 min per sample for their preparation, analysis, and data extraction, and less than 3 h for quantification. A lower limit of quantification (LLOQ) of 5 ng/mL in plasma was retrieved. The method was fully validated, following the guidelines of the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for bioanalytical method validation. The present developments prove the importance to consider alternative MS assays for time-efficient quantification of small molecule inhibitors in plasma in the context of personalized medicine for targeted therapies.