Assessment of pheniramine in alternative biological matrices by liquid chromatography tandem mass spectrometry.

Abstract

Pheniramine is an over-the-counter antihistamine drug. Its accessibility and low cost made it more popular among drug abusers in Pakistan. In this study, pheniramine was quantified in both conventional and alternative specimens of twenty chronic drug abusers, aged 16-50years, who were positive for pheniramine in comprehensive toxicological screening for drugs by gas chromatography with mass spectral detection in positive electron impact mode. Pheniramine was extracted from biological specimens using solid phase extraction and liquid chromatography tandem mass spectrometry was employed for quantification. Chromatographic separation was carried out on a Poroshell120EC-18 (2.1mm × 50mm × 2.7µm) column using water-acetonitrile in formic acid (0.1%) mobile phase in gradient elution mode with 500μL/min flow rate. Positive electrospray ionization mode and multi-reaction monitoring with ion transitionsm/z241.3 → 195.8 and 167.1 for pheniramine andm/zm/z247.6 → 173.1 for pheniramine-d6 were employed. The quantification method showed good linear ranges of 2-1000ng/mL in blood, urine, and oral fluid; 2-1000ng/mg in hair and 5-1000ng/mg in nail with ≥ 0.985% coefficient of linearity. The retention time of pheniramine was 3.0 ± 0.1min. The detection and lower quantification limits were 1ng/mL and 2ng/mL for blood, urine, oral fluid and hair whereas 2.5ng/mg and 5ng/mg for nail, respectively. Mean extraction recovery and ionization suppression ranged 86.3-95.1% and -4.6 to -14.4% in the studied matrices. Intra-day and inter-day precision were 4.1-9.3% and 2.8-11.2%, respectively. Pheniramine levels in specimens of drug abusers were 23-480ng/mL in blood, 72-735ng/mL in urine, 25-379ng/mL in oral fluid, 10-170ng/mg in hair and 8-86ng/mg in nail specimens. Alternative specimens are of utmost significance in clinical and medico-legal cases. In this study, authors compared matrix-matched calibration curves to blood calibration curve and obtained results within ± 10%; thereby justifying the use of blood calibration curve for urine, oral fluid, hair, and nail specimens.