Bioanalysis of alpelisib using liquid chromatography–tandem mass spectrometry and application to pharmacokinetic study

Abstract Alpelisib is the first alpha-specific phosphatidylinositol-3-kinase (PI3K) inhibitor indicated for the treatment of hormone receptor-positive, human epidermal growth factor receptor 2-negative, PI3K catalytic subunit alpha-mutated, advanced, or metastatic breast cancer. Substantial attempts have been made to extend its clinical use to other types of cancer. Analytical methods proven to accurately quantify alpelisib would improve the reliability of the preclinical and clinical data of alpelisib. Therefore, we developed and validated a quantification method based on liquid chromatography–tandem mass spectrometry for alpelisib in mouse and human plasma samples. Alpelisib and an internal standard (IS; enzalutamide) were separated from endogenous substances using an XTerra MS C18 column with a linear gradient of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Multiple reaction monitoring transitions for alpelisib and the IS were m/z 442.1 > 328.0 and m/z 465.0 > 209.1, respectively. The calibration curve for alpelisib was confirmed to be linear in the range of 1–2000ng/mL in both mouse and human plasma. The intra- and inter-day accuracy and precision met the acceptance criteria, and no significant matrix effects were observed. Alpelisib was stable under various storage and handling conditions, and the carryover effect was overcome using the injection loop flushing method. We successfully used this assay to study the in vitro metabolic profiles and in vivo pharmacokinetics of alpelisib in mice. Here, to the best of our knowledge, we report for the first time a valid quantitative method for alpelisib in mouse and human plasma, which could aid in providing valuable pharmacokinetic information on alpelisib to increase its clinical availability

Model-Based Prediction of Acid Suppression and Proposal of a New Dosing Regimen of Fexuprazan in Humans

Fexuprazan is a potassium-competitive acid blocker (P-CAB). The compounds in this newly developed drug family suppress intragastric acidity. As there are already other acid-suppressing drugs on the market, such as H-2 antagonists and proton pump inhibitors (PPIs), it would be informative to compare the biological effects of fexuprazan against another approved drug with the same indication. The drug concentration predicted by the pharmacokinetic (PK) model could serve as an input function for a pharmacodynamic (PD) model. The apparent pharmacokinetics of fexuprazan could be described by a simpler model. However, a physiologically based pharmacokinetic (PBPK) model was developed in a previous study. A one-compartment model was also proposed in the present study. Both the newly suggested model and the previously validated PBPK model were used as input functions of the PD models. Our simulation revealed that the effects of fexuprazan could be effectively simulated by the proposed PK-PD models. A PK-PD model was also proposed for the oral administration of the PPI reference drug esomeprazole. A model-based analysis was then performed for intragastric pH using several dosing methods. The expected pH could be predicted for both drugs under several dosing regimens using the proposed PK-PD models.N

Findings on In Vitro Transporter-Mediated Drug Interactions and Their Follow-Up Actions for Labeling: Analysis of Drugs Approved by US FDA between 2017 and 2021

Understanding possible follow-up actions on in vitro findings helps determine the necessity of labeling for drug interactions. We analyzed information for in vitro findings on transporter-mediated interactions of drugs approved by the U.S. Food and Drug Administration’s Center for Drug Evaluation and Research for the last five years (i.e., 2017–2021) and their follow-up actions for labeling. Higher R values than the pre-defined cut-off were observed with 3.7–39.1% inhibitor drugs in a simple prediction. Among these drugs, 16–41.7% were labeled with their potential drug interactions, while results of supporting studies or scientific rationales were submitted for the other drugs leading to no interaction labeling. In vitro transporter substrates were reported with 1.7–67.6% of drugs. The interaction labels for these substrate drugs were observed in up to 40% of drugs, while the other drugs were not labeled on the drug interactions with claims for their low interaction potential, evidenced by clinical studies or scientific rationales. The systematic and comprehensive analysis in this study will provide insight into the management of in vitro findings for transporter substrate or inhibitor drugs

Development of Physiologically Based Pharmacokinetic Model for Orally Administered Fexuprazan in Humans

Fexuprazan is a new drug candidate in the potassium-competitive acid blocker (P-CAB) family. As proton pump inhibitors (PPIs), P-CABs inhibit gastric acid secretion and can be used to treat gastric acid-related disorders such as gastroesophageal reflux disease (GERD). Physiologically based pharmacokinetic (PBPK) models predict drug interactions as pharmacokinetic profiles in biological matrices can be mechanistically simulated. Here, we propose an optimized and validated PBPK model for fexuprazan by integrating in vitro, in vivo, and in silico data. The extent of fexuprazan tissue distribution in humans was predicted using tissue-to-plasma partition coefficients in rats and the allometric relationships of fexuprazan distribution volumes (VSS) among preclinical species. Urinary fexuprazan excretion was minimal (0.29–2.02%), and this drug was eliminated primarily by the liver and metabolite formation. The fraction absorbed (Fa) of 0.761, estimated from the PBPK modeling, was consistent with the physicochemical properties of fexuprazan, including its in vitro solubility and permeability. The predicted oral bioavailability of fexuprazan (38.4–38.6%) was within the range of the preclinical datasets. The Cmax, AUClast, and time-concentration profiles predicted by the PBPK model established by the learning set were accurately predicted for the validation sets

A population PK-PD model of YH4808, a novel P-CAB, and intragastric pH that incorporated negative feedback by increased intragastric pH onto the systemic exposure to YH4808

YH4808 is a novel potassium-competitive acid blocker that is under clinical development to treat patients with gastroesophageal reflux disease and peptic ulcer diseases. In this study, the pharmacokinetic (PK) and pharmacodynamic (PD) profiles of YH4808 were modeled in healthy male volunteers who received a single oral dose of YH4808 at 30, 50, 100, 200, 400, 600, and 800 mg or matching placebo and multiple once-daily oral doses of YH4808 at 100, 200, and 400 mg or matching placebo for 7 days. A population PK-PD model adequately described the time-concentration-effect profiles of YH4808. The maximum increasing effect of YH4808 on intragastric pH was 4.38, which was higher than the observed maximum increase in intragastric pH after omeprazole at 40 mg (2.2 in pH). The maximum inhibitory effect by the increased intragastric pH on the exposure to repeated YH4808 was 58% from baseline. Monte-Carlo simulation experiments based on the final model showed that YH4808 at 200 mg will produce a higher percentage of time at pH > 4 over 24 h on day 1 than observed value of esomeprazole at 40 mg once-daily, an active comparator (84.7% time vs. 58.3% time, respectively). Because YH4808 at >= 200 mg resulted in a higher percentage of time at intragastric pH > 4 than seen after once-daily esomeprazole at 40 mg and YH4808 showed acceptable tolerability at a single-dose of 30-800 mg, we suggest to test the 200 mg once daily dosage regimen in further clinical trials of YH4808.N

Pharmacokinetic Estimation Models-based Approach to Predict Clinical Implications for CYP Induction by Calcitriol in Human Cryopreserved Hepatocytes and HepaRG Cells

Calcitriol, a vitamin D3 metabolite, is approved for various indications because it is the bioactive form of vitamin D in the body. The purpose of this study was to predict the clinical significance of cytochrome P450 (CYP) induction by calcitriol using in vitro human cryopreserved hepatocytes, HepaRG experimental systems, and various pharmacokinetic estimation models. CYP2B6, 3A4, 2C8, and 2C9 mRNA levels increased in a concentration-dependent manner in the presence of calcitriol in human cryopreserved hepatocytes and HepaRG cells. Using the half maximal effective concentration (EC50) and maximum induction effect (Emax) obtained from the in vitro study, a basic kinetic model was applied, suggesting clinical relevance. In addition, a static mechanistic model showed the improbability of a clinically significant effect; however, the calculated area under the plasma concentration–time curve ratio (AUCR) was marginal for CYP3A4 in HepaRG cells. To clarify the effect of CYP3A4 in vivo, physiologically based pharmacokinetic (PBPK) modeling was applied as a dynamic mechanistic model, revealing a low clinically significant effect of CYP3A4 induction by calcitriol. Therefore, we conclude that CYP induction by calcitriol treatment would not be clinically significant under typical clinical conditions

Integration of a Physiologically Based Pharmacokinetic and Pharmacodynamic Model for Tegoprazan and Its Metabolite: Application for Predicting Food Effect and Intragastric pH Alterations

A physiologically based pharmacokinetic/pharmacodynamic (PBPK/PD) model for tegoprazan and its major metabolite M1 was developed to predict PK and PD profiles under various scenarios. The PBPK model for tegoprazan and M1 was developed and predicted using the SimCYP® simulator and verified using clinical study data obtained after a single administration of tegoprazan. The established PBPK/PD model was used to predict PK profiles after repeated administrations of tegoprazan, postprandial PK profiles, and intragastric pH changes. The predicted tegoprazan and M1 concentration–time profiles fit the observed profiles well. The arithmetic mean ratios (95% confidence intervals) of the predicted to observed values for the area under the curve (AUC0–24 h), maximum plasma drug concentration (Cmax), and clearance (CL) for tegoprazan and M1 were within a 30% interval. Delayed time of maximum concentration (Tmax) and decreased Cmax were predicted in the postprandial PK profiles compared with the fasted state. This PBPK/PD model may be used to predict PK profiles after repeated tegoprazan administrations and to predict differences in physiological factors in the gastrointestinal tract or changes in gastric acid pH after tegoprazan administration

Electrical impedance spectroscopy and diagnosis of tendinitis

There have been a number of studies that investigate the usefulness of bioelectric signals in diagnoses and treatment in the medical field. Tendinitis is a musculoskeletal disorder with a very high rate of occurrence. This study attempts to examine whether electrical impedance spectroscopy (EIS) can detect pathological changes in a tendon and find the exact location of the lesion. Experimental tendinitis was induced by injecting collagenase into one side of the patellar tendons in rabbits, while the other side was used as the control. After measuring the impedance in the tendinitis and intact tendon tissue, the dissipation factor was computed. The real component of impedance and the dissipation factor turned out to be lower in tendinitis than in intact tissues. Moreover, the tendinitis dissipation factor spectrum showed a clear difference from that of the intact tendon, indicating its usefulness as a tool for detecting the location of the lesion. Pathologic findings from the tissues that were obtained after measuring the impedance confirmed the presence of characteristics of tendinitis. In conclusion, EIS is a useful method for diagnosing tendinitis and detecting the lesion location in invasive treatment.UCHIYAMA T, 2008, J TISSUE VIABILITY, V17, P110Tarulli AW, 2006, PHYSIOL MEAS, V27, P1269, DOI 10.1088/0967-3334/27/12/002Keshtkar A, 2006, PHYSIOL MEAS, V27, P585, DOI 10.1088/0967-3334/27/7/003Ardic F, 2006, AM J PHYS MED REHAB, V85, P53, DOI 10.1097/01.phm.0000179518.85484.53Sierpowska J, 2005, PHYSIOL MEAS, V26, pS119, DOI 10.1088/0967-3334/26/2/012Werner RA, 2005, J OCCUP REHABIL, V15, P37, DOI 10.1007/s10926-005-0872-1Edinger J, 2005, VET COMP ORTHOPAED, V18, P209Teefey SA, 2004, J HAND SURG-AM, V29A, P393, DOI 10.1016/j.jhsa.2004.02.001SEOANE F, 2004, C P IEEE ENG MED BIO, V3, P2322Li T, 2003, MAGN RESON IMAGING, V21, P741, DOI 10.1016/S0730-725X(03)00177-2Wilkinson BA, 2002, J UROLOGY, V168, P1563d`Entremont MI, 2002, MED BIOL ENG COMPUT, V40, P380Pasternack I, 2001, ACTA RADIOL, V42, P434Wright T, 2001, SEMIN ULTRASOUND CT, V22, P383, DOI 10.1053/sult.2001.25057O`Connell MP, 2000, BRIT J OBSTET GYNAEC, V107, P1040Gonzalez-Correa CA, 2000, MED BIOL ENG COMPUT, V38, P373Teefey SA, 2000, J BONE JOINT SURG AM, V82A, P498Swen WAA, 2000, RHEUMATOLOGY, V39, P55Paulsen KD, 1999, RADIAT RES, V152, P41Stone D, 1999, J ORTHOPAED RES, V17, P168Casas O, 1999, ANN NY ACAD SCI, V873, P51Read JW, 1998, J SHOULDER ELB SURG, V7, P264ALMEKINDERS LC, 1998, J AM ACAD ORTHOP SUR, V6, P157Peh WCG, 1998, BRIT J RADIOL, V71, P31Wnorowski DC, 1997, ARTHROSCOPY, V13, P710Gabriel C, 1996, PHYS MED BIOL, V41, P2231, DOI 10.1088/0031-9155/41/11/001Gabriel S, 1996, PHYS MED BIOL, V41, P2251, DOI 10.1088/0031-9155/41/11/002Blad B, 1996, PHYSIOL MEAS, V17, pA105, DOI 10.1088/0967-3334/17/4A/015Schloerb PR, 1996, AM J CLIN NUTR, V64, pS510FOSTER KR, 1996, HDB BIOL EFFECTS ELEOSYPKA M, 1995, PHYSIOL MEAS, V16, pA49, DOI 10.1088/0967-3334/16/3A/005STEENDIJK P, 1994, BASIC RES CARDIOL, V89, P411HEROUX P, 1994, ANN BIOMED ENG, V22, P328KUN S, 1994, ENG ADV NEW OPP BIOMMISAMORE GW, 1991, J BONE JOINT SURG AM, V73A, P704IANNOTTI JP, 1991, J BONE JOINT SURG AM, V73A, P17BIERMANN H, 1991, FORTSCHR OPHTHALMOL, V88, P17MCCORMACK RR, 1990, J RHEUMATOL, V17, P958ZHENG E, 1984, IEEE T BIO-MED ENG, V31, P477GRUCHOW HW, 1979, AM J SPORTS MED, V7, P234JAMES SL, 1978, AM J SPORTS MED, V6, P40MOBLEY BA, 1974, J GEN PHYSIOL, V63, P625

In Vivo Toxicity and Pharmacokinetics of Polytetrafluoroethylene Microplastics in ICR Mice

The increased use of plastics has led to severe environmental pollution, particularly by microplastics—plastic particles 5 mm or less in diameter. These particles are formed by environmental factors such as weathering and ultraviolet irradiation, thereby making environmental pollution worse. This environmental pollution intensifies human exposure to microplastics via food chains. Despite potential negative effects, few toxicity assessments on microplastics are available. In this study, two sizes of polytetrafluoroethylene (PTFE) microplastics, approximately 5 μm and 10–50 μm, were manufactured and used for single and four-week repeated toxicity and pharmacokinetic studies. Toxicological effects were comprehensively evaluated with clinical signs, body weight, food and water consumption, necropsy findings, and histopathological and clinical-pathological examinations. Blood collected at 15, 30 60, and 120 min after a single administration of microplastics were analyzed by Raman spectroscopy. In the toxicity evaluation of single and four-week repeated oral administration of PTFE microplastics, no toxic changes were observed. Therefore, the lethal dose 50 (LD50) and no-observed-adverse-effect-level (NOAEL) of PTFE microplastics in ICR mice were established as 2000 mg/kg or more. PTFE microplastics were not detected in blood, so pharmacokinetic parameters could not be calculated. This study provides new insight into the long-term toxicity and pharmacokinetics of PTFE microplastics