Pretreatment and non-specific binding in ultrafiltration device: Impact on protease inhibitor quantification

Area of Science:

• Pharmaceutical Sciences
• Analytical Chemistry
• Biotechnology

Background:

• Ultrafiltration (UF) is crucial for separating unbound drugs.
• Non-specific binding (NSB) can limit UF accuracy.
• Pretreatment strategies are explored to mitigate NSB in UF devices.

Purpose of the Study:

• To evaluate pretreatment methods for UF devices.
• To assess the effectiveness in reducing NSB of protease inhibitors (PIs).

Main Methods:

• Tested two PIs: lopinavir (LPV) and ritonavir (RTV).
• Pretreated UF devices with ultrapure water, Tween-20, or Tween-80.
• Quantified NSB using LC-MS/MS after exposing pretreated devices to analyte solutions.

Main Results:

• UF devices pretreated with 5% Tween exhibited the lowest NSB for both LPV and RTV.
• NSB ranged from 7-11% (low conc.) and 16-34% (high conc.) for LPV.
• NSB was approximately 6% (low conc.) and 18% (high conc.) for RTV.
• Incomplete Tween removal could lead to NSB overestimation.

Conclusions:

• Pretreatment of UF devices with Tween, followed by thorough removal, effectively reduces NSB.
• This optimization improves the reliability of UF for PI analysis.