Non-Steroidal Drug Interferences in a Quantitative Multisteroid LC-MS/MS Assay

Area of Science:

• Clinical Chemistry
• Mass Spectrometry
• Pharmaceutical Analysis

Background:

• Steroid quantification assays using LC-MS/MS typically screen for steroidal interferences.
• Interferences from non-steroidal drugs in these assays have not been systematically explored.
• The development of multi-analyte methods can compromise assay specificity.

Purpose of the Study:

• To investigate potential interferences from non-steroidal pharmaceuticals in a multisteroid LC-MS/MS assay.
• To identify specific non-steroidal drugs that interfere with steroid measurements.
• To assess the clinical relevance of newly discovered interferences.

Main Methods:

• Screening of over 150 pharmaceuticals and metabolites using commercial quality control samples.
• Utilized a multisteroid LC-MS/MS assay with protein precipitation and HybridSPE filtration.
• Employed a biphenyl column with a methanol-water gradient and NH4F additive.

Main Results:

• Identified paroxetine (antidepressant) as an interference to 17-hydroxyprogesterone (17P).
• Discovered a triazolam metabolite (α-hydroxytriazolam) interfering with aldosterone (ALDO) quantification.
• Observed overlapping signals from M+1 isotopologues of paroxetine and the triazolam metabolite with target analytes.

Conclusions:

• Non-steroidal drugs can interfere with LC-MS/MS steroid quantification, posing clinical relevance due to overlapping signals and differing concentration ranges.
• Screening for interferences in multi-analyte assays should extend beyond steroidal compounds to include common non-steroidal drugs.
• Assay development for high-throughput steroid analysis requires careful consideration of potential interferences from diverse drug classes to maintain selectivity and specificity.