Research Article
Syed N Alvi, Saleh Al Dgith
Abstract
A rapid liquid chromatographic tandem mass spectrometric (LC-MS/MS) assay for the measurement of clarithromycin level in human plasma was developed and validated using erythromycin as internal standard (IS). Analysis was performed at room temperature using a reversed phase Atlantis dC18 (2.1 × 100 mm, 3 μm) column. The components of interest were detected in the positive ion mode of electrospray ionization using transition 749 → 158.4 and 719.3 → 158.2 for clarithromycin and the IS, respectively. Quantification and detection limits were 5 and 2 ng/ml, respectively. Mean extraction recovery was ≥ 86% for clarithromycin and 99% for the IS. Relationship between clarithromycin concentration and peak height ratio of clarithromycin to the IS was linear (R2 ≥ 0.9833) in the range of 0.005-4.0 μg/ml, and the intra- and inter-day coefficient of variations were 2.9% to 13.1% and 2.5% to 9.6%, respectively. Clarithromycin in human plasma was stable for at least 24 hours at room temperature (≥ 83%) or 14 weeks at -20°C (≥ 93%), and after three freeze-thaw cycles (≥ 83%). The method was successfully used to determine clarithromycin levels in human plasma samples obtained from a healthy volunteer.