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Kimura N, Takahashi H, Sakamoto S, Yanagi Y, Maeshima N, Minamimoto A, Iwamoto N, Shimada T, Nagai R, Aizawa K. Microvolume Analysis of Aflibercept in Aqueous Humor Using Mass Spectrometry. Transl Vis Sci Technol 2022; 11:7. [PMID: 35671043 PMCID: PMC9187940 DOI: 10.1167/tvst.11.6.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To develop a microvolume analytical method for measurement of the aflibercept concentration in human intraocular fluid and plasma. Methods We analyzed trace amounts of aflibercept in human aqueous humor using Fab-selective proteolysis and nano-surface and molecular-orientation limited (nSMOL) proteolysis, coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS). Patients with age-related macular degeneration or diabetic macular edema were recruited. Just after an injection of 50 µL of aflibercept, regurgitate from needle holes was collected with a micropipette pressed to the side of the injection hole within 10 seconds. The median amount of regurgitate was 4 µL (range, 1–18 µL). Results In human plasma, the aflibercept concentration ranged between 0.195 and 50 µg/mL when using the quantitative signature peptide IIWDSR (aa. 56–61) present on the vascular endothelial growth factor receptor 1 domain of aflibercept. The method was validated by evaluating its linearity, carryover, selectivity, accuracy and precision, dilution effect, and sample/processing stability. As only a minimal amount of regurgitate through needle holes can be sampled, we performed and verified the aflibercept assay using patient samples after 1:10 dilution with control human plasma, a recognized diluent. The median concentration of aflibercept in the regurgitate was 240 µg/mL (range, 13–4300 µg/mL). Conclusions Our findings indicate that the aflibercept assay using human intraocular fluid can be reliably performed using nSMOL coupled with LC-MS/MS. Translational Relevance This technique for quantifying aflibercept in the regurgitate suggests that the amount of drug lost post-injection can be ignored, even in patients with a relatively large leak after vitreous injection. This new methodology suggests possible therapeutic responses and may be employed as a general analytical method for trapping many biologics, such as vascular endothelial growth factor, in various types of clinical samples, unaffected by proteinaceous or small organic pharmaceuticals.
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Affiliation(s)
- Natsuka Kimura
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Hidenori Takahashi
- Department of Ophthalmology, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Shinichi Sakamoto
- Department of Ophthalmology, Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Yasuo Yanagi
- Department of Ophthalmology and Microtechnology, Yokohama City University, Yokohama, Kanagawa, Japan.,Singapore National Eye Centre, Singapore Eye Research Institute, Singapore, Singapore
| | - Nozomi Maeshima
- Global Application Development Center, Shimadzu Corporation, Hadano, Kanagawa, Japan
| | - Ayaka Minamimoto
- Global Application Development Center, Shimadzu Corporation, Hadano, Kanagawa, Japan
| | - Noriko Iwamoto
- Shimadzu Bioscience Research Partnership, Shimadzu Scientific Instruments, Inc., Bothell, WA, USA
| | - Takashi Shimada
- Shimadzu Bioscience Research Partnership, Shimadzu Scientific Instruments, Inc., Bothell, WA, USA
| | - Ryozo Nagai
- Jichi Medical University, Shimotsuke, Tochigi, Japan
| | - Kenichi Aizawa
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke, Tochigi, Japan.,Clinical Pharmacology Center, Jichi Medical University Hospital, Shimotsuke, Tochigi, Japan
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Kikkawa HS, Kobayashi M, Minamimoto A, Ono H, Tsuge K. Simultaneous determination of eight catechins and four theaflavins in bottled tea by liquid chromatography-tandem mass spectrometry for forensic analysis. J Forensic Sci 2021; 67:309-320. [PMID: 34405405 DOI: 10.1111/1556-4029.14864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 07/12/2021] [Accepted: 08/02/2021] [Indexed: 11/28/2022]
Abstract
Tea, and particularly bottled tea, is widely consumed worldwide and is often encountered at crime scenes in poisoning cases or used in place of urine in drug abuse monitoring. Tea is a rich source of polyphenols, such as catechins and theaflavins, and these compounds are useful for identification of trace quantities of tea samples. However, information on the contents of catechins and theaflavins in bottled tea is limited. In this study, a method was developed for simultaneous analysis of eight catechins and four theaflavins in tea using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The concentrations of these polyphenols were determined in bottled black, oolong, and green teas after a simple pretreatment process by the standard addition method. The developed LC-MS/MS method was rapid and all tested polyphenol compounds were separated within ~14 min. All tea types contained all the catechins, at varying concentrations, but not all the theaflavins were present in all the tea types. This indicates that the theaflavin composition reflects the degree of the fermentation and could be used for discrimination among different types of tea. All the green tea samples contained all eight catechins; however, the concentrations of these compounds varied among the tea samples. Principal component analysis and hierarchical cluster analysis were useful for discrimination of samples. It has been unclear whether the variations of chemical components are useful for forensic discrimination. Our results demonstrate that, in addition to identification of tea varieties, catechins and theaflavins can be used for the discrimination of bottled tea samples.
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Affiliation(s)
| | - Manami Kobayashi
- Shimadzu Corporation Global Application Development Center Analytical & Measuring Instruments Division, Hadano, Japan
| | - Ayaka Minamimoto
- Shimadzu Corporation Global Application Development Center Analytical & Measuring Instruments Division, Hadano, Japan
| | - Hiromi Ono
- Shimadzu Corporation Global Application Development Center Analytical & Measuring Instruments Division, Hadano, Japan
| | - Kouichiro Tsuge
- National Research Institute of Police Science, Kashiwa, Japan
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