Document Type

Poster Presentation

Publication Date

11-7-2026

Abstract

Objective.

Benzalkonium chloride (BAK) is a widely used pharmaceutical preservative composed of a mixture of homologs, mainly the C12, C14, and C16 homologs. Due to its permanent positive charge and hydrophobic chain, BAK can adsorb onto HPLC vial surfaces, leading to erroneous analytical results. This study evaluated the compatibility of selected QIS vials with dilute BAK solutions and compared their performance with that of other leading premium brands.

Methods.

Nine QIS vial types (from Pursuit Scientific) and two other premium brands were obtained for evaluation. A 25 ppm BAK solution was prepared in a pH 6.5 phosphate buffer. The solution was aliquoted into each vial and analyzed by HPLC at 0.5, 15, 30, 45, and 60 minutes. The percentages of each BAK homolog and total BAK remaining were calculated relative to the time-zero values. Three replicate vials of each type were evaluated.

Results.

BAK loss was observed in all vial types over the 60-minute evaluation period, with the C16 homolog generally exhibiting the greatest loss. Among the glass vials, the QIS LS and DA vials demonstrated the best compatibility, with 96.0% and 96.1% of total BAK remaining after 60 minutes, respectively. In comparison, the Thermo Level 3 glass vials exhibited the greatest loss among the glass types, with 92.4% of total BAK remaining. Contrary to findings from previous studies, the three polypropylene vial types did not provide better compatibility than the best-performing glass vials. This difference might be due to variations in vial interior geometry, which affect the surface area-to-volume ratio.

Conclusion.

The QIS LS and DA glass vials demonstrated the best compatibility with the dilute BAK solution among all types evaluated. These findings highlight the importance of assessing vial compatibility during HPLC method development. Future work will evaluate whether pre- saturation can further reduce sorption loss.

Comments

Poster presented at 52nd Annual Rochester Academy of Science (RAS), November 7, 2026.

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