Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity
Introduction: Sulfobutylether-b-cyclodextrin (SBE-CD) is a pharmaceutical excipient known to bind verapamil. Following intravenous administration, clearance of SBE-CD approximates glomerular filtration rate. We hypothesized that infusion of SBE-CD would increase time to asystole in a rat model of ve...
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| Format: | Article |
| Language: | English |
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eScholarship Publishing, University of California
2012-04-01
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| Series: | Western Journal of Emergency Medicine |
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| Online Access: | http://escholarship.org/uc/item/07p476t8 |
| _version_ | 1818026607576612864 |
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| author | Allan R. Mottram Sean M. Bryant Steven E. Aks |
| author_facet | Allan R. Mottram Sean M. Bryant Steven E. Aks |
| author_sort | Allan R. Mottram |
| collection | DOAJ |
| description | Introduction: Sulfobutylether-b-cyclodextrin (SBE-CD) is a pharmaceutical excipient known to bind verapamil. Following intravenous administration, clearance of SBE-CD approximates glomerular filtration rate. We hypothesized that infusion of SBE-CD would increase time to asystole in a rat model of verapamil toxicity in a dose-dependent manner. The objective was to demonstrate the effect of a range of SBE-CD concentrations in a rat model of verapamil toxicity. Methods: Twenty-five Wistar rats were allocated to control or 1 of 4 intervention groups. All received ketamine and diazepam anesthesia followed by verapamil infusion 32 mg/kg/h. The verapamil infusion for the intervention groups was premixed with SBE-CD in a 1:1, 1:2, 1:4, or 1:8 molar ratio (verapamil to SBE-CD). The control group infusion did not contain SBE-CD. Additional saline or water was added to the infusion so that the total volume infused was the same across groups, and the osmolality was maintained as close to physiologic as possible. Heart rate, respiratory rate, and temperature were monitored. The primary endpoint was time to asystole.Results: Verapamil coinfused with SBE-CD in a molar ratio of 1:4 resulted in prolonged time to asystole compared to control (21.2 minutes vs 17.6 minutes, P , 0.05). There were no differences in time to asystole between control and any other intervention group. There was no significant difference in time to apnea between control and any intervention group. We assessed the effect of a range of SBE-CD concentrations and identified 1 concentration that prolonged time to asystole. Mechanismsthat may explain this effect include optimal volume expansion with a hyperosmolar cyclodextrin containing solution, complexation of verapamil within the hydrophobic cyclodextrin pore, and/or complexation within micelle-like aggregates of cyclodextrin. However, mechanistic explanations for the observed findings are speculative at this point. Conclusion: The 1:4 verapamil to SBE-CD concentration was modestly effective with SBE-CD concentrations above and below this range demonstrating nonstatistically significant improvements in time to asystole. [West J Emerg Med. 2012;13(1):63–67.] |
| first_indexed | 2024-12-10T04:34:42Z |
| format | Article |
| id | doaj.art-f27e3ee72df24e98a3f245a0c5ffda28 |
| institution | Directory Open Access Journal |
| issn | 1936-900X 1936-9018 |
| language | English |
| last_indexed | 2024-12-10T04:34:42Z |
| publishDate | 2012-04-01 |
| publisher | eScholarship Publishing, University of California |
| record_format | Article |
| series | Western Journal of Emergency Medicine |
| spelling | doaj.art-f27e3ee72df24e98a3f245a0c5ffda282022-12-22T02:02:03ZengeScholarship Publishing, University of CaliforniaWestern Journal of Emergency Medicine1936-900X1936-90182012-04-011316367Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil ToxicityAllan R. MottramSean M. BryantSteven E. AksIntroduction: Sulfobutylether-b-cyclodextrin (SBE-CD) is a pharmaceutical excipient known to bind verapamil. Following intravenous administration, clearance of SBE-CD approximates glomerular filtration rate. We hypothesized that infusion of SBE-CD would increase time to asystole in a rat model of verapamil toxicity in a dose-dependent manner. The objective was to demonstrate the effect of a range of SBE-CD concentrations in a rat model of verapamil toxicity. Methods: Twenty-five Wistar rats were allocated to control or 1 of 4 intervention groups. All received ketamine and diazepam anesthesia followed by verapamil infusion 32 mg/kg/h. The verapamil infusion for the intervention groups was premixed with SBE-CD in a 1:1, 1:2, 1:4, or 1:8 molar ratio (verapamil to SBE-CD). The control group infusion did not contain SBE-CD. Additional saline or water was added to the infusion so that the total volume infused was the same across groups, and the osmolality was maintained as close to physiologic as possible. Heart rate, respiratory rate, and temperature were monitored. The primary endpoint was time to asystole.Results: Verapamil coinfused with SBE-CD in a molar ratio of 1:4 resulted in prolonged time to asystole compared to control (21.2 minutes vs 17.6 minutes, P , 0.05). There were no differences in time to asystole between control and any other intervention group. There was no significant difference in time to apnea between control and any intervention group. We assessed the effect of a range of SBE-CD concentrations and identified 1 concentration that prolonged time to asystole. Mechanismsthat may explain this effect include optimal volume expansion with a hyperosmolar cyclodextrin containing solution, complexation of verapamil within the hydrophobic cyclodextrin pore, and/or complexation within micelle-like aggregates of cyclodextrin. However, mechanistic explanations for the observed findings are speculative at this point. Conclusion: The 1:4 verapamil to SBE-CD concentration was modestly effective with SBE-CD concentrations above and below this range demonstrating nonstatistically significant improvements in time to asystole. [West J Emerg Med. 2012;13(1):63–67.]http://escholarship.org/uc/item/07p476t8CyclodextrinVerapamilCardiotoxicityRat |
| spellingShingle | Allan R. Mottram Sean M. Bryant Steven E. Aks Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity Western Journal of Emergency Medicine Cyclodextrin Verapamil Cardiotoxicity Rat |
| title | Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity |
| title_full | Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity |
| title_fullStr | Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity |
| title_full_unstemmed | Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity |
| title_short | Dose Dependent Response to Cyclodextrin Infusion in a Rat Model of Verapamil Toxicity |
| title_sort | dose dependent response to cyclodextrin infusion in a rat model of verapamil toxicity |
| topic | Cyclodextrin Verapamil Cardiotoxicity Rat |
| url | http://escholarship.org/uc/item/07p476t8 |
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