Development and Validation of a Headspace GC–MS Method for Simultaneous Quantification of Antimicrobial Preservatives in Biopharmaceutical Peptide Formulations

The four most used antimicrobial preservatives in biopharmaceutical parenteral formulations are phenol, meta-cresol, chlorobutanol, and benzyl alcohol. Preservatives are included in various combinations in biopharmaceuticals highlighting the importance of an analytical method to quantify the four preservatives simultaneously. A headspace GC-MS method was developed to quantify phenol, chlorobutanol, meta-cresol, and benzyl alcohol. The method was validated according to USP <1225>. System suitability <USP 621> was conducted daily for retention time (%RSD < 2.0%), peak area (%RSD < 5.0%), USP tailing factor (< 2.0 and %RSD < 10.0%), and peak resolution (> 2.0). Analytical ranges were 1.5-90 μg/mL for phenol and meta-cresol, 30-240 μg/mL for benzyl alcohol, and 30-300 μg/mL for chlorobutanol. Method accuracy ranged from 94% to 108% and precision from 4% to 15 %RSD for all the tested preservatives. The method was applied to three marketed teriparatide drug products selected as a model. Preservative concentrations of the biopharmaceutical marketed products were determined and were found to be comparable with the labeled concentrations, except for an expired product with 2.5% of the label claim. The developed headspace GC-MS method can be used to evaluate the drug quality of the parenteral formulations and to support the assessment of biopharmaceutical peptide drug products.