1
|
Hanaoka H, Ohshima Y, Suzuki Y, Yamaguchi A, Watanabe S, Uehara T, Nagamori S, Kanai Y, Ishioka NS, Tsushima Y, Endo K, Arano Y. Development of a Widely Usable Amino Acid Tracer: ⁷⁶Br-α-Methyl-Phenylalanine for Tumor PET Imaging. J Nucl Med 2015; 56:791-7. [PMID: 25814518 DOI: 10.2967/jnumed.114.152215] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/03/2015] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Radiolabeled amino acids are superior PET tracers for the imaging of malignant tumors, and amino acids labeled with (76)Br, an attractive positron emitter because of its relatively long half-life (16.2 h), could potentially be a widely usable tumor imaging tracer. In this study, in consideration of its stability and tumor specificity, we designed two (76)Br-labeled amino acid derivatives, 2-(76)Br-bromo-α-methyl-l-phenylalanine (2-(76)Br-BAMP) and 4-(76)Br-bromo-α-methyl-l-phenylalanine (4-(76)Br-BAMP), and investigated their potential as tumor imaging agents. METHODS Both (76)Br- and (77)Br-labeled amino acid derivatives were prepared. We performed in vitro and in vivo stability studies and cellular uptake studies using the LS180 colon adenocarcinoma cell line. Biodistribution studies in normal mice and in LS180 tumor-bearing mice were performed, and the tumors were imaged with a small-animal PET scanner. RESULTS Both (77)Br-BAMPs were stable in the plasma and in the murine body. Although both (77)Br-BAMPs were taken up by LS180 cells and the uptake was inhibited by L-type amino acid transporter 1 inhibitors, 2-(77)Br-BAMP exhibited higher uptake than 4-(77)Br-BAMP. In the biodistribution studies, 2-(77)Br-BAMP showed more rapid blood clearance and lower renal accumulation than 4-(77)Br-BAMP. More than 90% of the injected radioactivity was excreted in the urine by 6 h after the injection of 2-(77)Br-BAMP. High tumor accumulation of 2-(77)Br-BAMP was observed in tumor-bearing mice, and PET imaging with 2-(76)Br-BAMP enabled clear visualization of the tumors. CONCLUSION 2-(77)Br-BAMP exhibited preferred pharmacokinetics and high LS180 tumor accumulation, and 2-(76)Br-BAMP enabled clear visualization of the tumors by PET imaging. These findings suggest that 2-(76)Br-BAMP could constitute a potential new PET tracer for tumor imaging and may eventually enable the wider use of amino acid tracers.
Collapse
Affiliation(s)
- Hirofumi Hanaoka
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, Maebashi, Japan Department of Molecular Imaging and Radiotherapy, Graduate School of Pharmaceutical Science, Chiba University, Chiba, Japan
| | - Yasuhiro Ohshima
- Medical Radioisotope Application Group, Life Science and Biotechnology Division, Quantum Beam Science Center, Research Department of Nuclear Science, Japan Atomic Energy Agency, Takasaki, Japan
| | - Yurika Suzuki
- Department of Molecular Imaging and Radiotherapy, Graduate School of Pharmaceutical Science, Chiba University, Chiba, Japan
| | - Aiko Yamaguchi
- Department of Bioimaging Information Analysis, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Shigeki Watanabe
- Medical Radioisotope Application Group, Life Science and Biotechnology Division, Quantum Beam Science Center, Research Department of Nuclear Science, Japan Atomic Energy Agency, Takasaki, Japan
| | - Tomoya Uehara
- Department of Molecular Imaging and Radiotherapy, Graduate School of Pharmaceutical Science, Chiba University, Chiba, Japan
| | - Shushi Nagamori
- Division of Biosystem Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Japan; and
| | - Yoshikatsu Kanai
- Division of Biosystem Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Japan; and
| | - Noriko S Ishioka
- Medical Radioisotope Application Group, Life Science and Biotechnology Division, Quantum Beam Science Center, Research Department of Nuclear Science, Japan Atomic Energy Agency, Takasaki, Japan
| | - Yoshito Tsushima
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Keigo Endo
- Department of Diagnostic Radiology and Nuclear Medicine, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Yasushi Arano
- Department of Molecular Imaging and Radiotherapy, Graduate School of Pharmaceutical Science, Chiba University, Chiba, Japan
| |
Collapse
|
2
|
Gao N, Fang Y, Qi B, Jia LJ, Jin H, Qiao HL. Pharmacokinetic changes of unbound theophylline are due to plasma protein binding displacement and CYP1A2 activity inhibition by baicalin in rats. JOURNAL OF ETHNOPHARMACOLOGY 2013; 150:477-484. [PMID: 24076258 DOI: 10.1016/j.jep.2013.08.062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2012] [Revised: 07/23/2013] [Accepted: 08/29/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Baicalin is one of the major bioactive constituents of Scutellariae Radix, the root of Scutellariae baicalensis Georgi and possesses a wide variety of pharmacological properties. AIM OF THE STUDY To elucidate the effect of baicalin on the pharmacokinetics of theophylline in rats, focusing on plasma protein binding displacement and inhibition effect on CYP1A2 in vivo and in vitro. MATERIALS AND METHODS The study was a randomized, three-period crossover design. Nine rats were given saline (control) or 450 mg/kg baicalin (dosage regimen A or B). Dosage regimen A was administered once at 0 h. Dosage regimen B was divided into three dosages (225,112.5, 112.5 mg/kg) and was given at 0, 2 and 4 h, respectively. Then theophylline (5 mg/kg, i.v.) was administered immediately. The effect of baicalin on CYP1A2 activity was determined by metabolism of phenacetin in vitro and plasma protein binding of theophylline was determined by ultrafiltration. RESULTS C(max) decreased from (12.4 ± 1.6) to (8.7 ± 0.9) and (8.6 ± 2.0) mg/L, T(1/2) increased by 116 and 96%, V(d) increased by 51 and 49% for total theophylline in rats treated with dosage regimen A and B of baicalin, respectively. Cmax was significantly increased, V(d) decreased by 43 and 29% for unbound theophylline in rats treated with dosage regimen A and B of baicalin, respectively (P < 0.01). T(1/2) of unbound theophylline increased by 104% only in rats treated with dosage regimen B. No significant effects on the CL and AUC of both total and unbound theophylline were observed in the rats treated with dosage regimen A, but the CL decreased and AUC increased for total theophylline and CL decreased for unbound theophylline in the group treated with dosage regimen B (P < 0.05). Correlation analysis showed that the mean unbound theophylline (%) and mean baicalin concentration was in good correlation (P < 0.01). Baicalin decreased metabolism of phenacetin and exhibited a mixed-type inhibition in rat liver microsomes, with a K(i) value of 88.1 μM in vitro. Moreover baicalin was a competitive displacer of theophylline from plasma protein in vitro. CONCLUSIONS The changes in Cmax, T(1/2), CL and AUC of theophylline due to baicalin may be attributed to two mechanisms, plasma protein binding displacement and CYP1A2 activity inhibition.
Collapse
Affiliation(s)
- Na Gao
- Department of Clinical Pharmacology, School of Medicine, Zhengzhou University, Zhengzhou 450052, China
| | | | | | | | | | | |
Collapse
|
3
|
Yamasaki K, Chuang VTG, Maruyama T, Otagiri M. Albumin-drug interaction and its clinical implication. Biochim Biophys Acta Gen Subj 2013; 1830:5435-43. [PMID: 23665585 DOI: 10.1016/j.bbagen.2013.05.005] [Citation(s) in RCA: 297] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Revised: 04/30/2013] [Accepted: 05/02/2013] [Indexed: 01/22/2023]
Abstract
BACKGROUND Human serum albumin acts as a reservoir and transport protein for endogenous (e.g. fatty acids or bilirubin) and exogenous compounds (e.g. drugs or nutrients) in the blood. The binding of a drug to albumin is a major determinant of its pharmacokinetic and pharmacodynamic profile. SCOPE OF REVIEW The present review discusses recent findings regarding the nature of drug binding sites, drug-albumin binding in certain diseased states or in the presence of coadministered drugs, and the potential of utilizing albumin-drug interactions in clinical applications. MAJOR CONCLUSIONS Drug-albumin interactions appear to predominantly occur at one or two specific binding sites. The nature of these drug binding sites has been fundamentally investigated as to location, size, charge, hydrophobicity or changes that can occur under conditions such as the content of the endogenous substances in question. Such findings can be useful tools for the analysis of drug-drug interactions or protein binding in diseased states. A change in protein binding is not always a problem in terms of drug therapy, but it can be used to enhance the efficacy of therapeutic agents or to enhance the accumulation of radiopharmaceuticals to targets for diagnostic purposes. Furthermore, several extracorporeal dialysis procedures using albumin-containing dialysates have proven to be an effective tool for removing endogenous toxins or overdosed drugs from patients. GENERAL SIGNIFICANCE Recent findings related to albumin-drug interactions as described in this review are useful for providing safer and efficient therapies and diagnoses in clinical settings. This article is part of a Special Issue entitled Serum Albumin.
Collapse
Affiliation(s)
- Keishi Yamasaki
- Faculty of Pharmaceutical Sciences, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan; DDS Research Institute, Sojo University, 4-22-1 Ikeda, Kumamoto 860-0082, Japan
| | | | | | | |
Collapse
|
4
|
Nishi K, Kobayashi M, Nishii R, Shikano N, Takamura N, Kuga N, Yamasaki K, Nagamachi S, Tamura S, Otagiri M, Kawai K. Pharmacokinetic Alteration of 99mTc-MAG3 using Serum Protein Binding Displacement Method. Nucl Med Biol 2013; 40:366-70. [DOI: 10.1016/j.nucmedbio.2012.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 11/26/2012] [Accepted: 12/01/2012] [Indexed: 10/27/2022]
|
5
|
Kawai K. [Regulation of pharmacokinetics and targeting-confirmative personalized medicine]. Nihon Hoshasen Gijutsu Gakkai Zasshi 2011; 67:249-259. [PMID: 21471682 DOI: 10.6009/jjrt.67.249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Keiichi Kawai
- Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Science, Kanazawa University and Biomedical Imaging Research Center, Fukui University
| |
Collapse
|