The frequently used sympathomimetic drug phenylephrine has been studied by electrospray ionisation-mass spectrometry. The stability of the adrenoceptor agonist was examined by investigations of the pharmaceutically used salts phenylephrine hydrochloride and phenylephrine bitartrate. Photostability has been studied by use of an irradiation equipment emitting a solar radiation spectrum. The experiments were carried out by analysis of aqueous drug solutions before and after irradiation treatment. The phenylephrine derivative with unsaturated side chain originating from the drug by loss of one water molecule has been detected as the major degradation product of both phenylephrine salts the hydrochloride and the bitartrate. Further degradation and oxidation products were detectable already in the full scan mode demonstrating a low stability of the drug. Tandem mass spectrometry and multiple stage mass spectrometry experiments enabled the establishment of fragmentation schemes of both salts for the first time. Irradiation treatment indicated that phenylephrine bitartrate is more prone to degradation than the hydrochloride because of an additional decomposition sensitivity of the tartaric acid counter ion. An interaction between phenylephrine and its counter ion degradation products via a nucleophilic addition mechanism is suggested to be the explanation for the detected ion signals after irradiation treatment of phenylephrine bitartrate.
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http://dx.doi.org/10.1016/j.jpba.2010.01.024 | DOI Listing |
Pharmacol Res
October 2021
Department of Anesthesiology, College of Medicine Tucson, University of Arizona, USA; Department of Physiology, College of Medicine Tucson, University of Arizona, USA; Department of Pharmacology and Toxicology, College of Pharmacy Tucson, University of Arizona, USA. Electronic address:
Background: Vascular dysfunction is a checkpoint to the development of hypertension. Heparan sulfate proteoglycans (HSPG) participate in nitric oxide (NO) and calcium signaling, key regulators of vascular function. The relationship between HSPG-mediated NO and calcium signaling and vascular dysfunction has not been explored.
View Article and Find Full Text PDFEur J Pharmacol
October 2015
Laboratory of Cardiovascular Pharmacology, Department of Pharmacology, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil. Electronic address:
We evaluated the effects of K+ channel blockers in the vascular reactivity of in vitro perfused kidneys, as well as on the influence of vasoactive agents in the renal blood flow of rats subjected to the cecal ligation and puncture (CLP) model of sepsis. Both norepinephrine and phenylephrine had the ability to increase the vascular perfusion pressure reduced in kidneys of rats subjected to CLP at 18 h and 36 h before the experiments. The non-selective K+ channel blocker tetraethylammonium, but not the Kir6.
View Article and Find Full Text PDFVascul Pharmacol
September 2015
Laboratory of Pharmacology, Faculty of Medicine of Marília, SP, Brazil. Electronic address:
Norepinephrine (NE) responses are larger in renal and femoral veins compared to phenylephrine (PE). These differences may be due to the subtypes of adrenoceptor involved in these responses or to the involvement of local modulatory mechanisms. Therefore, the present study investigated in organ bath the adrenoceptor subtypes involved in the NE and PE responses in both renal and femoral veins as well as the influence of local mechanisms related to NO and to prostanoids upon these responses.
View Article and Find Full Text PDFSe Pu
November 2010
College of Chemistry and Materials Sciences, Fujian Normal University, Fuzhou 350108, China.
A method for the determination of three adrenergic drugs, including phenylephrine hydrochloride (PHE), metaraminol bitartrate (MR) and isoprenaline hydrochloride (IP), was developed using capillary electrophoresis with amperometric detection. The detection potential of working electrode was 0.950 V versus the reference electrode of Ag/AgCl.
View Article and Find Full Text PDFJ Pharm Biomed Anal
June 2010
Martin-Luther-University Halle-Wittenberg, School of Pharmacy, Institute of Pharmaceutics and Biopharmaceutics, Wolfgang-Langenbeck-Strasse 4, D-06120 Halle, Saale, Germany.
The frequently used sympathomimetic drug phenylephrine has been studied by electrospray ionisation-mass spectrometry. The stability of the adrenoceptor agonist was examined by investigations of the pharmaceutically used salts phenylephrine hydrochloride and phenylephrine bitartrate. Photostability has been studied by use of an irradiation equipment emitting a solar radiation spectrum.
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