Title

Quantification of Free Phenytoin by Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS).

Document Type

Article

Publication Date

1-1-2016

Identifier

DOI: 10.1007/978-1-4939-3252-8_25

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.

Journal Title

Methods in molecular biology (Clifton, N.J.)

Volume

1383

First Page

241

Last Page

246

MeSH Keywords

Anticonvulsants; Chromatography, Liquid; Drug Monitoring; Humans; Phenytoin; Tandem Mass Spectrometry; Ultrafiltration

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