The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Rosendo Obach - One of the best experts on this subject based on the ideXlab platform.
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simultaneous determination of paracetamol and Chlorpheniramine in human plasma by liquid chromatography tandem mass spectrometry
Journal of Chromatography A, 2000Co-Authors: C Celma, J A Allue, J Prunonosa, C Peraire, Rosendo ObachAbstract:Abstract An analytical method for the determination of paracetamol and Chlorpheniramine in human plasma has been developed, validated and applied to the analysis of samples from a phase I clinical trial. The analytical method consists in the extraction of paracetamol and Chlorpheniramine with diethyl ether, followed by the determination of both drugs by an LC–MS–MS method, using 2-acetamidophenol as internal standard. The intra-assay and inter-assay precision and accuracy of this technique were good and the limit of quantitation was 0.5 μg/ml of plasma for paracetamol and 0.2 ng/ml for Chlorpheniramine. The concentration working range was established between 0.5 μg/ml and 25 μg/ml for paracetamol and between 0.2 ng/ml and 50 ng/ml for Chlorpheniramine. This method has been used for analyzing more than 1200 human plasma samples from a clinical study with 24 volunteers.
Nobuyuki Okamura - One of the best experts on this subject based on the ideXlab platform.
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neuroimaging of histamine h1 receptor occupancy in human brain by positron emission tomography pet a comparative study of ebastine a second generation antihistamine and Chlorpheniramine a classical antihistamine
British Journal of Clinical Pharmacology, 2008Co-Authors: Masaaki Tagawa, Michiaki Matsuda, Yasuyuki Mizuki, Michiko Kano, Nobuyuki Okamura, Makoto Higuchi, Hiroyuki Arai, R Iwata, Toshihiko Fujii, Sadao KomemushiAbstract:Aims Sedation induced by antihistamines is widely recognized to be caused by their penetration through the blood-brain-barrier and the consequent occupation of brain histamine H 1 -receptors. We previously studied the mechanism of sedation caused by antihistamines using positron emission tomography (PET). Recently, we revealed the nonsedative characteristic of ebastine, a second-generation antihistamine, with cognitive performance tests. In the present study. H 1 -receptor occupation by ebastine was examined in the human brain using PET. Methods Ebastine 10 mg and (+)-Chlorpheniramine 2 or 6 mg were orally given to healthy male volunteers. PET scans with [ 11 C]-doxepin, a potent H 1 -receptor antagonist, were conducted near t max of respective drugs. Other volunteers in the control group also received PET scans. The binding potential of doxepin (BP = Bmax/ K d ) for available brain H 1 -receptors was imaged on a voxel-by-voxel basis through graphical analysis. By setting regions of interest, the H 1 -receptor occupancy of drugs was calculated in several H 1 -receptor rich regions. Results Brain distribution of radioactivity after ebastine treatment was similar to that without any drugs. However, after the oral administration of 2 mg (+)-Chlorpheniramine, the level was lower than after ebastine and nondrug treatments. Graphical analysis followed by statistical parametric mapping (SPM96) revealed that H 1 -receptor rich regions such as cortices, cingulate gyrus and thalamus were regions where the BPs after ebastine were significantly higher than after (+)-Chlorpheniramine (2 mg). H 1 -receptor occupancies in cortex were approximately 10% by ebastine and ≥50% by either dose of (+)-Chlorpheniramine (95% confidence interval for difference in the mean receptor occupancies: 27%, 54% for 2 mg and 35%, 62% for 6 mg vs ebastine, respectively). Receptor occupancies increased with increasing plasma concentration of (+)-Chlorpheniramine, but not with concentration of carebastine, an active metabolite of ebastine. Conclusions Ebastine (10 mg orally) causes brain histamine H 1 -receptor occupation of approximately 10%, consistent with its lower incidence of sedative effect, whereas (+)-Chlorpheniramine occupied about 50% of brain H 1 -receptors even at a low but sedative dose of 2 mg; occupancy of (+)-Chlorpheniramine was correlated with plasma (+)-Chlorpheniramine concentration.
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effects of a sedative antihistamine d Chlorpheniramine on regional cerebral perfusion and performance during simulated car driving
Human Psychopharmacology-clinical and Experimental, 2008Co-Authors: Manabu Tashiro, Nobuyuki Okamura, Hiroyuki Arai, Yumiko Sakurada, Hideki Mochizuki, Etsuo Horikawa, Masahiro Maruyama, Shoichi Watanuki, Masatoshi ItohAbstract:OBJECTIVES: The sedative side effects of antihistamines have been recognized to be potentially dangerous in car driving, but the mechanism underlying these effects has not yet been elucidated to date. The aim of the present study is to examine regional cerebral blood flow (rCBF) responses during a simulated car-driving task following oral administration of D-Chlorpheniramine using positron emission tomography (PET) and [15O]H2O, based on a single-blind cross-over study-design. METHODS: Right-handed, healthy male volunteers (n = 14) drove a car in a simulated environment following oral administration of D-Chlorpheniramine repetab 6 mg or placebo. Their rCBF was measured using PET with [15O]H2O in the following three conditions: (1) resting, (2) active driving, and (3) passive driving. All 'in-car' views during the simulated driving were videotaped and used for rating driving performance. RESULTS: Performance evaluation revealed that the number of lane deviations significantly increased in the D-Chlorpheniramine condition compared with the placebo condition (p Language: en
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functional neuroimaging of cognition impaired by a classical antihistamine d Chlorpheniramine
British Journal of Pharmacology, 2000Co-Authors: Nobuyuki Okamura, Makoto Higuchi, R Iwata, Kazuhiko Yanai, Jun Sakai, Hidetada Sasaki, Takehiko Watanabe, Masatoshi ItohAbstract:1 Antihistamine induced cognitive decline was evaluated using positron emission tomography (PET) measurement of histamine H1 receptor (H1R) occupancy and regional cerebral blood flow (rCBF). 2 Cognitive performance in attention-demanding task deteriorated dose-dependently and the eAects were statistically significant after the treatment of 2 mg of d-Chlorpheniramine. There was no significant change in subjective sleepiness in the same dose. 3 The regional blockade of H1R was observed mainly in the frontal, temporal and anterior cingulate cortices, and the intravenous administration of d-Chlorpheniramine as a therapeutic dose (2 mg) blocked over 60% of H1R in the frontal cortices. 4 The results from activation study using visual discrimination tasks demonstrated that enhanced activity in the right prefrontal and anterior cingulate cortices as well as a decreased activity in the left temporal and frontal cortices and midbrain after the treatment of d-Chlorpheniramine. 5 There were no changes in global CBF for the subjects treated with 2 mg d-Chlorpheniramine (pre; 44.8+3.3 ml dl 71 min 71 vs post; 44.4+4.7 ml dl 71 min 71 ). 6 The results indicated that the attention system of human brain could be altered by therapeutic doses of H1R antagonists. These findings provide the information as to the potential risk of antihistamines in our daily activities. British Journal of Pharmacology (2000) 129, 115‐123
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Functional neuroimaging of cognition impaired by a classical antihistamine, d‐Chlorpheniramine
British Journal of Pharmacology, 2000Co-Authors: Nobuyuki Okamura, Makoto Higuchi, Kazuhiko Yanai, Jun Sakai, Hidetada Sasaki, Takehiko Watanabe, Ren Iwata, Masatoshi ItohAbstract:1 Antihistamine induced cognitive decline was evaluated using positron emission tomography (PET) measurement of histamine H1 receptor (H1R) occupancy and regional cerebral blood flow (rCBF). 2 Cognitive performance in attention-demanding task deteriorated dose-dependently and the eAects were statistically significant after the treatment of 2 mg of d-Chlorpheniramine. There was no significant change in subjective sleepiness in the same dose. 3 The regional blockade of H1R was observed mainly in the frontal, temporal and anterior cingulate cortices, and the intravenous administration of d-Chlorpheniramine as a therapeutic dose (2 mg) blocked over 60% of H1R in the frontal cortices. 4 The results from activation study using visual discrimination tasks demonstrated that enhanced activity in the right prefrontal and anterior cingulate cortices as well as a decreased activity in the left temporal and frontal cortices and midbrain after the treatment of d-Chlorpheniramine. 5 There were no changes in global CBF for the subjects treated with 2 mg d-Chlorpheniramine (pre; 44.8+3.3 ml dl 71 min 71 vs post; 44.4+4.7 ml dl 71 min 71 ). 6 The results indicated that the attention system of human brain could be altered by therapeutic doses of H1R antagonists. These findings provide the information as to the potential risk of antihistamines in our daily activities. British Journal of Pharmacology (2000) 129, 115‐123
Jhijoung Wang - One of the best experts on this subject based on the ideXlab platform.
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Chlorpheniramine produces cutaneous analgesia in rats
Pharmacological Reports, 2019Co-Authors: Chong Chi Chiu, Yu Wen Chen, Ching Hsia Hung, Jhijoung WangAbstract:Background This study sought to assess the cutaneous (peripheral) analgesic effects of antihistamine Chlorpheniramine, compared with the long-lasting local anesthetic bupivacaine. Methods After Chlorpheniramine and bupivacaine were subcutaneously injected under the dorsal skin of the rats, the cutaneous analgesia effect was quantitatively evaluated by scoring the number to which the animal failed to react (cutaneous trunci muscle reflex). The quality and duration of Chlorpheniramine and bupivacaine on infiltrative cutaneous analgesia were compared. Results We revealed that subcutaneous Chlorpheniramine, as well as the local anesthetic bupivacaine elicited cutaneous analgesia in a dosage-dependent manner. Based on their ED_50s (50% effective doses), the relative potency was found to be Chlorpheniramine [1.13 (1.05–1.22) μmol]
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Chlorpheniramine produces cutaneous analgesia in rats
Pharmacological Reports, 2019Co-Authors: Chong Chi Chiu, Yu Wen Chen, Ching Hsia Hung, Jhijoung WangAbstract:This study sought to assess the cutaneous (peripheral) analgesic effects of antihistamine Chlorpheniramine, compared with the long-lasting local anesthetic bupivacaine. After Chlorpheniramine and bupivacaine were subcutaneously injected under the dorsal skin of the rats, the cutaneous analgesia effect was quantitatively evaluated by scoring the number to which the animal failed to react (cutaneous trunci muscle reflex). The quality and duration of Chlorpheniramine and bupivacaine on infiltrative cutaneous analgesia were compared. We revealed that subcutaneous Chlorpheniramine, as well as the local anesthetic bupivacaine elicited cutaneous analgesia in a dosage-dependent manner. Based on their ED50s (50% effective doses), the relative potency was found to be Chlorpheniramine [1.13 (1.05–1.22) μmol]
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Chlorpheniramine produces spinal motor proprioceptive and nociceptive blockades in rats
European Journal of Pharmacology, 2015Co-Authors: Jann Inn Tzeng, Yu Wen Chen, Ching Hsia Hung, Jhijoung WangAbstract:Abstract This study aimed to assess the local anesthetic effects of Chlorpheniramine in spinal anesthesia and is compared with mepivacaine, a widely-used local anesthetic. Spinal anesthesia with Chlorpheniramine and mepivacaine was constructed in a dosage-dependent fashion after the rats were injected intrathecally. The spinal block effect of Chlorpheniramine in motor function, nociception, and proprioception was compared to that of mepivacaine. We revealed that intrathecal Chlorpheniramine and mepivacaine exhibited a dose-dependent spinal block of motor function, nociception, and proprioception. On the 50% effective dose (ED50) basis, the ranks of potencies in motor function, nociception, and proprioception were Chlorpheniramine>mepivacaine (P
Masatoshi Itoh - One of the best experts on this subject based on the ideXlab platform.
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effects of a sedative antihistamine d Chlorpheniramine on regional cerebral perfusion and performance during simulated car driving
Human Psychopharmacology-clinical and Experimental, 2008Co-Authors: Manabu Tashiro, Nobuyuki Okamura, Hiroyuki Arai, Yumiko Sakurada, Hideki Mochizuki, Etsuo Horikawa, Masahiro Maruyama, Shoichi Watanuki, Masatoshi ItohAbstract:OBJECTIVES: The sedative side effects of antihistamines have been recognized to be potentially dangerous in car driving, but the mechanism underlying these effects has not yet been elucidated to date. The aim of the present study is to examine regional cerebral blood flow (rCBF) responses during a simulated car-driving task following oral administration of D-Chlorpheniramine using positron emission tomography (PET) and [15O]H2O, based on a single-blind cross-over study-design. METHODS: Right-handed, healthy male volunteers (n = 14) drove a car in a simulated environment following oral administration of D-Chlorpheniramine repetab 6 mg or placebo. Their rCBF was measured using PET with [15O]H2O in the following three conditions: (1) resting, (2) active driving, and (3) passive driving. All 'in-car' views during the simulated driving were videotaped and used for rating driving performance. RESULTS: Performance evaluation revealed that the number of lane deviations significantly increased in the D-Chlorpheniramine condition compared with the placebo condition (p Language: en
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functional neuroimaging of cognition impaired by a classical antihistamine d Chlorpheniramine
British Journal of Pharmacology, 2000Co-Authors: Nobuyuki Okamura, Makoto Higuchi, R Iwata, Kazuhiko Yanai, Jun Sakai, Hidetada Sasaki, Takehiko Watanabe, Masatoshi ItohAbstract:1 Antihistamine induced cognitive decline was evaluated using positron emission tomography (PET) measurement of histamine H1 receptor (H1R) occupancy and regional cerebral blood flow (rCBF). 2 Cognitive performance in attention-demanding task deteriorated dose-dependently and the eAects were statistically significant after the treatment of 2 mg of d-Chlorpheniramine. There was no significant change in subjective sleepiness in the same dose. 3 The regional blockade of H1R was observed mainly in the frontal, temporal and anterior cingulate cortices, and the intravenous administration of d-Chlorpheniramine as a therapeutic dose (2 mg) blocked over 60% of H1R in the frontal cortices. 4 The results from activation study using visual discrimination tasks demonstrated that enhanced activity in the right prefrontal and anterior cingulate cortices as well as a decreased activity in the left temporal and frontal cortices and midbrain after the treatment of d-Chlorpheniramine. 5 There were no changes in global CBF for the subjects treated with 2 mg d-Chlorpheniramine (pre; 44.8+3.3 ml dl 71 min 71 vs post; 44.4+4.7 ml dl 71 min 71 ). 6 The results indicated that the attention system of human brain could be altered by therapeutic doses of H1R antagonists. These findings provide the information as to the potential risk of antihistamines in our daily activities. British Journal of Pharmacology (2000) 129, 115‐123
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Functional neuroimaging of cognition impaired by a classical antihistamine, d‐Chlorpheniramine
British Journal of Pharmacology, 2000Co-Authors: Nobuyuki Okamura, Makoto Higuchi, Kazuhiko Yanai, Jun Sakai, Hidetada Sasaki, Takehiko Watanabe, Ren Iwata, Masatoshi ItohAbstract:1 Antihistamine induced cognitive decline was evaluated using positron emission tomography (PET) measurement of histamine H1 receptor (H1R) occupancy and regional cerebral blood flow (rCBF). 2 Cognitive performance in attention-demanding task deteriorated dose-dependently and the eAects were statistically significant after the treatment of 2 mg of d-Chlorpheniramine. There was no significant change in subjective sleepiness in the same dose. 3 The regional blockade of H1R was observed mainly in the frontal, temporal and anterior cingulate cortices, and the intravenous administration of d-Chlorpheniramine as a therapeutic dose (2 mg) blocked over 60% of H1R in the frontal cortices. 4 The results from activation study using visual discrimination tasks demonstrated that enhanced activity in the right prefrontal and anterior cingulate cortices as well as a decreased activity in the left temporal and frontal cortices and midbrain after the treatment of d-Chlorpheniramine. 5 There were no changes in global CBF for the subjects treated with 2 mg d-Chlorpheniramine (pre; 44.8+3.3 ml dl 71 min 71 vs post; 44.4+4.7 ml dl 71 min 71 ). 6 The results indicated that the attention system of human brain could be altered by therapeutic doses of H1R antagonists. These findings provide the information as to the potential risk of antihistamines in our daily activities. British Journal of Pharmacology (2000) 129, 115‐123
C Celma - One of the best experts on this subject based on the ideXlab platform.
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simultaneous determination of paracetamol and Chlorpheniramine in human plasma by liquid chromatography tandem mass spectrometry
Journal of Chromatography A, 2000Co-Authors: C Celma, J A Allue, J Prunonosa, C Peraire, Rosendo ObachAbstract:Abstract An analytical method for the determination of paracetamol and Chlorpheniramine in human plasma has been developed, validated and applied to the analysis of samples from a phase I clinical trial. The analytical method consists in the extraction of paracetamol and Chlorpheniramine with diethyl ether, followed by the determination of both drugs by an LC–MS–MS method, using 2-acetamidophenol as internal standard. The intra-assay and inter-assay precision and accuracy of this technique were good and the limit of quantitation was 0.5 μg/ml of plasma for paracetamol and 0.2 ng/ml for Chlorpheniramine. The concentration working range was established between 0.5 μg/ml and 25 μg/ml for paracetamol and between 0.2 ng/ml and 50 ng/ml for Chlorpheniramine. This method has been used for analyzing more than 1200 human plasma samples from a clinical study with 24 volunteers.