Validation of HPLC-MS/MS methods for analysis of loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide in human plasma

  • Bioanalysis. 2010 Dec;2(12):1989-2000. doi: 10.4155/bio.10.156.
Jennifer S D Zimmer  1 ,  Shane R Needham ,  Chad D Christianson ,  Crystal M Piekarski ,  Chrystal N Sheaff ,  Keith Huie ,  Andrea R Reed ,  Lori Takahashi
Affiliations
  • 1. Alturas Analytics, Inc., 1324 Alturas Drive, Moscow, ID 83843, USA. [email protected]
PMID: 21110742 DOI: 10.4155/bio.10.156
Abstract

Background: Two ESI-LC-MS/MS methods were validated for the quantitative analysis of loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide in human K(2)EDTA plasma. Cation-exchange solid-phase extraction (SPE) was used to extract loxapine, amoxapine and the two hydroxylated metabolites, and organic precipitation was used to quantify loxapine N-oxide.

Results: Both methods were shown to be accurate (±13%), intra-assay precision was less than 15%, and inter-assay precision was less than 10% in all instances across the entire dynamic range of the assays (0.0500-50.0 ng/ml for the SPE method and 0.100-25.0 ng/ml for the precipitation method).

Conclusion: The validated methods for loxapine, amoxapine, 7-OH-loxapine, 8-OH-loxapine and loxapine N-oxide have been used to successfully support clinical trials.

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