Development and Validation of Analytical Method Using Gas Chromatography with Triple Quadrupole Mass Spectrometry for the Detection of Alkyl Halides as Potential Genotoxic Impurities in Posaconazole

Abstract

Effective risk management and control methods for potentially genotoxic impurities (PGIs), including alkyl halides, are of significant importance in the medicinal (pharmaceutical) sector. The three alkyl halides in posaconazole are PGIs. The detection and assessment of genotoxic substances is a top priority for all regulatory organizations. Quantifying PGIs at trace levels using standard analytical techniques, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), is challenging for the pharmaceutical manufacturing industry. Thus, the detection of trace quantities of PGIs in posaconazole is essential for developing sensitive analytical methodologies. The objective of this study was to establish an analytical technique for quantifying the three PGIs (alkyl halides) in posaconazole and its intermediate. These alkyl halides are 1-(2,4-difluorophenyl) ethan-1-one (PGI-1), (Z)-1-(1-bromoprop-1-en-2-yl)- 2,4-difluorobenzene (PGI-2), and 1-bromo-2-(2,4-difluorophenyl) propan-2-ol (PGI-3). To identify trace quantities (parts per million (ppm)) of these impurities, we employed a gas chromatography (GC-MS/MS) equipped with a triple quadrupole mass spectrometry detector. The GC column was a USP phase G43, which is a mid-polar 6% cyanopropyl; 94% polydimethylsiloxane, with a 60 m length, 0.32 mm inner diameter, and 1.8 μm film thickness. Helium (He) was used as the carrier gas, with a flow rate of 1.5 mL/min. A thermal gradient elution program was used for this procedure. The method was calibrated for the three PGIs with limits of detection (LOD) and quantification (LOQ) of 0.01 and 0.025 ppm, respectively. The linear range of concentrations (25–150%) was maintained with respect to the specification level. This method was validated according to the ICH regulations and was shown to be specific, rugged, robust, precise, sensitive, accurate, linear, and stable. Therefore, in this newly developed method, the combination of suitable analytical techniques, such as GC-MS/MS and proper chromatographic conditions and column selection with the lowest LOD and LOQ, have allowed the induction of excellent ionization. These conditions have successfully facilitated the identification of PGI-1, PGI-2, and PGI-3 in posaconazole and its intermediate during routine analysis.