Abstract
Phenytoin (diphenylhydantoin) is an anticonvulsant drug that has been used for decades for the treatment of many types of seizures. The drug is highly protein bound and measurement of free-active form of the drug is warranted particularly in patients with conditions that can affect drug protein binding. Here, we describe a LC/MS/MS method for the measurement of free phenytoin. Free drug is separated by ultrafiltration of serum or plasma. Ultrafiltrate is treated with acetonitrile containing internal standard phenytoin d-10 to precipitate proteins. The mixture is centrifuged and supernatant is injected onto LC-MS-MS, and analyzed using multiple reaction monitoring. This method is linear from 0.1 to 4.0 μg/mL and does not demonstrate any significant ion suppression or enhancement.
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Peat, J., Frazee, C., Garg, U. (2016). Quantification of Free Phenytoin by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). In: Garg, U. (eds) Clinical Applications of Mass Spectrometry in Drug Analysis. Methods in Molecular Biology, vol 1383. Humana Press, New York, NY. https://doi.org/10.1007/978-1-4939-3252-8_25
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DOI: https://doi.org/10.1007/978-1-4939-3252-8_25
Publisher Name: Humana Press, New York, NY
Print ISBN: 978-1-4939-3251-1
Online ISBN: 978-1-4939-3252-8
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