Metabolic Stability Assessment of New PARP Inhibitor Talazoparib Using Validated LC-MS/MS Methodology: In silico Metabolic Vulnerability and Toxicity Studies.

Talazoparib (BMN673) is a new poly(ADP-ribose) polymerase inhibitor that has been FDA approved for patients suffering from metastatic breast cancer with germline BRCA mutations. In the current study, an accurate and efficient liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical methodology was developed for TZB estimation in addition to its metabolic stability assessment. TZB and lapatinib (LAP) (which is chosen as an internal standard; IS) were separated using reversed phase elution system (Hypersil C18 column) with an isocratic mobile phase. The linearity range of the established method was 5-500 ng/mL (r2 ≥ 0.999) in the human liver microsomes (HLMs) matrix. Different parameters were calculated to confirm the method sensitivity (limit of quantification was 2.0 ng/mL), and reproducibility (intra- and inter-day precision and accuracy were below 3.1%) of our methodology. For evaluation of TZB metabolic stability in HLM matrix, intrinsic clearance (9.59 µL/min/mg) and in vitro half-life (72.7 mins) were calculated. TZB treatment discontinuations were reported due to adverse events and dose accumulation, so in silico metabolic vulnerability (experimental and in silico) and toxicity assessment (in silico) of TZB were performed utilizing P450 Metabolism and DEREK modules of StarDrop software. TZB is slowly metabolized by the liver. TZB was reported to be minimally metabolized by the liver that approved our outcomes. We do recommend that plasma levels be monitored in cases when talazoparib is used for a long period of time, since it is possible for TZB to bioaccumulate after multiple doses to toxic levels. According to our knowledge, the current method is considered the first LC-MS/MS methodology for evaluating TZB metabolic stability. Further drug discovery studies can be done depending on this concept allowing the designing of new series of compounds with more safety profile through reducing side effects and improving metabolic behavior.

Attwa MW ，Kadi AA ，Abdelhameed AS ，Alhazmi HA ... -  《Drug Design Development and Therapy》

A Validated LC-MS/MS Assay for the Simultaneous Quantification of the FDA-Approved Anticancer Mixture (Encorafenib and Binimetinib): Metabolic Stability Estimation.

Attwa MW ，Darwish HW ，Al-Shakliah NS ，Kadi AA ... -  《MOLECULES》

Development and Validation of a Rapid LC-MS/MS Method for Quantifying Alvocidib: In Silico and In Vitro Metabolic Stability Estimation in Human Liver Microsomes.

Attwa MW ，AlRabiah H ，Kadi AA 《MOLECULES》

LC-MS/MS Estimation of Rociletinib Levels in Human Liver Microsomes: Application to Metabolic Stability Estimation.

Rociletinib (CO-1686; RLC) is a new, small molecule that is orally administered to inhibit mutant-selective covalent inhibitor of most epidermal growth factor receptor (EGFR)-mutated forms, including T790M, L858R, and exon 19 deletions, but not exon 20 insertions. Non-small-cell lung cancer (NSCLC) with a gene mutation that encodes EGFR is sensitive to approved EGFR inhibitors, but usually resistance develops, which is frequently mediated by T790M EGFR mutation. RLC is an EGFR inhibitor found to be active in preclinical models of EGFR-mutated NSCLC with or without T790M. In silico drug metabolism prediction of RLC was executed with the aid of the WhichP450 module (StarDrop software package) to verify its metabolic liability. Second, a fast, accurate, and competent LC-MS/MS assay was developed for RLC quantification to determine its metabolic stability. RLC and bosutinib (BOS) (internal standard; IS) were separated using an isocratic elution system with a C18 column (reversed stationary phase). The developed LC-MS/MS analytical method showed linearity of 5-500 ng/mL with r2 ≥ 0.9998 in the human liver microsomes (HLMs) matrix. A limit of quantification of 4.6 ng/mL revealed the sensitivity of the analytical method, while the acquired inter- and intra-day accuracy and precision values below 4.63% inferred the method reproducibility. RLC metabolic stability estimation was calculated using intrinsic clearance (20.15 µL/min/mg) and in vitro half-life (34.39 min) values. RLC exhibited a moderate extraction ratio indicative of good bioavailability. The developed analytical method herein is the first LC-MS/MS assay for RLC metabolic stability.

Attwa MW ，Abdelhameed AS ，Kadi AA 《Drug Design Development and Therapy》

LC-MS/MS method for the quantification of the anti-cancer agent infigratinib: Application for estimation of metabolic stability in human liver microsomes.

Mostafa GAE ，Kadi AA ，AlMasoud N ，Attwa MW ，Al-Shakliah NS ，AlRabiah H ... -  《-》