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Li R, Chen Y, Jia M, Jiang X, Wang L. Pharmacokinetics and absorption mechanism of tandospirone citrate. Front Pharmacol 2023; 14:1283103. [PMID: 38027008 PMCID: PMC10657815 DOI: 10.3389/fphar.2023.1283103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 10/12/2023] [Indexed: 12/01/2023] Open
Abstract
Tandospirone citrate (TDS) is commonly used for the treatment of patients with generalized anxiety disorder in clinical practice, and several studies are developing new indications for TDS. However, the in vivo processes and absorption properties of TDS have not been systematically investigated. In this work, we conducted a comprehensive investigation using in vivo, in vitro, and ex vivo approaches, involving animal and cellular models, to examine the pharmacokinetic properties and absorption mechanisms of TDS. The results of in vivo studies revealed that the half-life (t 1/2) of TDS was 1.380 ± 0.46 h and 1.224 ± 0.39 h following intragastric (i.g.) and intravenous (i.v.) administration of 20 mg/kg TDS, respectively. This indicates that TDS is rapidly eliminated in rats. The area under the curve (AUC) of TDS after i.g. and i.v. administration was 114.7 ± 40 ng/mL*h and 48,400 ± 19,110 ng/mL*h, respectively, and the absolute bioavailability of TDS was found to be low (0.24%). Furthermore, TDS was extensively metabolized in rats, with the AUC of the major active metabolite [1-[2-pyrimidyl]-piperazine] being approximately 16.38-fold higher than that of TDS after i.g. administration. The results from the in vitro Caco-2 cell model and ex vivo everted gut sac experiment demonstrated that TDS exhibited good permeability, and its transport was influenced by concentration, temperature, and pH. Passive diffusion was identified as the main absorption mechanism. In conclusion, TDS is classified as a Biopharmaceutics Classification System (BCS) class I drug, characterized by high solubility and permeability. The low absolute bioavailability of TDS may be attributed to its rapid metabolism. The pharmacokinetic data and absorption characteristics obtained in this study provide fundamental information for the further development and utilization of TDS.
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Affiliation(s)
- Rong Li
- Antibiotics Research and Re-evaluation Key Laboratory of Sichuan Province, Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu, Sichuan, China
- Department of Clinical Pharmacy and Pharmacy Administration, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Yuwen Chen
- West China Hospital, West China School of Nursing, Sichuan University, Chengdu, Sichuan, China
| | - Mi Jia
- Department of Clinical Pharmacy and Pharmacy Administration, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Xuehua Jiang
- Department of Clinical Pharmacy and Pharmacy Administration, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
| | - Ling Wang
- Department of Clinical Pharmacy and Pharmacy Administration, Key Laboratory of Drug-Targeting and Drug Delivery System of the Education Ministry, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, China
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Dumouchel JL, Chemuturi N, Milton MN, Camenisch G, Chastain J, Walles M, Sasseville V, Gunduz M, Iyer GR, Argikar UA. Models and Approaches Describing the Metabolism, Transport, and Toxicity of Drugs Administered by the Ocular Route. Drug Metab Dispos 2018; 46:1670-1683. [DOI: 10.1124/dmd.118.082974] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 08/10/2018] [Indexed: 11/22/2022] Open
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Opportunities in low-level radiocarbon microtracing: applications and new technology. Future Sci OA 2015; 2:FSO74. [PMID: 28031933 PMCID: PMC5137946 DOI: 10.4155/fso.15.74] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 08/20/2015] [Indexed: 12/14/2022] Open
Abstract
14C-radiolabeled (radiocarbon) drug studies are central to defining the disposition of therapeutics in clinical development. Concerns over radiation, however, have dissuaded investigators from conducting these studies as often as their utility may merit. Accelerator mass spectrometry (AMS), originally designed for carbon dating and geochronology, has changed the outlook for in-human radiolabeled testing. The high sensitivity of AMS affords human clinical testing with vastly reduced radiative (microtracing) and chemical exposures (microdosing). Early iterations of AMS were unsuitable for routine biomedical use due to the instruments' large size and associated per sample costs. The situation is changing with advances in the core and peripheral instrumentation. We review the important milestones in applied AMS research and recent advances in the core technology platform. We also look ahead to an entirely new class of 14C detection systems that use lasers to measure carbon dioxide in small gas cells.
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Dave M, Nash M, Young GC, Ellens H, Magee MH, Roberts AD, Taylor MA, Greenhill RW, Boyle GW. Disposition and metabolism of darapladib, a lipoprotein-associated phospholipase A2 inhibitor, in humans. Drug Metab Dispos 2013; 42:415-30. [PMID: 24378325 DOI: 10.1124/dmd.113.054486] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The absorption, metabolism, and excretion of darapladib, a novel inhibitor of lipoprotein-associated phospholipase A2, was investigated in healthy male subjects using [(14)C]-radiolabeled material in a bespoke study design. Disposition of darapladib was compared following single i.v. and both single and repeated oral administrations. The anticipated presence of low circulating concentrations of drug-related material required the use of accelerator mass spectrometry as a sensitive radiodetector. Blood, urine, and feces were collected up to 21 days post radioactive dose, and analyzed for drug-related material. The principal circulating drug-related component was unchanged darapladib. No notable metabolites were observed in plasma post-i.v. dosing; however, metabolites resulting from hydroxylation (M3) and N-deethylation (M4) were observed (at 4%-6% of plasma radioactivity) following oral dosing, indicative of some first-pass metabolism. In addition, an acid-catalyzed degradant (M10) resulting from presystemic hydrolysis was also detected in plasma at similar levels of ∼5% of radioactivity post oral dosing. Systemic exposure to radioactive material was reduced within the repeat dose regimen, consistent with the notion of time-dependent pharmacokinetics resulting from enhanced clearance or reduced absorption. Elimination of drug-related material occurred predominantly via the feces, with unchanged darapladib representing 43%-53% of the radioactive dose, and metabolites M3 and M4 also notably accounting for ∼9% and 19% of the dose, respectively. The enhanced study design has provided an increased understanding of the absorption, distribution, metabolism and excretion (ADME) properties of darapladib in humans, and substantially influenced future work on the compound.
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Affiliation(s)
- Mehul Dave
- Department of Drug Metabolism and Pharmacokinetics (M.D., M.N., G.C.Y., A.D.R., M.A.T., G.W.B.) and Department of Safety Assessment (R.W.G.), GlaxoSmithKline Research & Development, Ware, United Kingdom, and Department of Drug Metabolism and Pharmacokinetics (H.E.) and Clinical Pharmacology, Modeling and Simulation (M.H.M.), GlaxoSmithKline Research & Development, Upper Merion, Philadelphia
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