NERDG 2026
Poster 31 Abstract
Analysis of Pembrolizumab in Biological Samples Using Sampling by ABS Plastic SPME and Quantitation by LC-MS/MS
Dylan Mattison, Michael Long, Eric Ng, Marcel Musteata
Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences
Presenting and Corresponding Author: Dylan Mattison, [email protected]
Purpose
This research aims to develop a method combining acrylonitrile butadiene styrene (ABS) plastic Solid Phase Microextraction (SPME) and Liquid-Chromatography Mass Spectroscopy (LC-MS/MS) techniques for the quantification of the anti-cancer, monoclonal antibody drug, pembrolizumab. Clinically, such a method would allow for therapeutic drug monitoring of pembrolizumab within blood and tumors, accessing the concentration of drug reaching the cancer site, and allowing for better dosing recommendations and more efficacious pembrolizumab treatment, while also demonstrating the first use of SPME for sampling proteins.
Methods
To test the overall effectiveness of various SPME approaches, calibration curves plotting the Amount of Extracted Pembrolizumab vs Amount of Pembrolizumab in Sample were created. These curves were analyzed for the SPME fiber yield, saturation, and precision. Additional experiments were done to manipulate certain materials or parameters of the method like oxidation, addition of coupling agents, and fiber thickness to observe how they may increase its robustness.
Results
Initially, various SPME materials were tested against one another. ABS plastic fibers were chosen for having the highest yield of those supports that still maintained reasonable precision (RSD<6%). However, those fibers became saturated at higher pembrolizumab levels, demonstrating the need for further modifications to increase the linear range. In one approach, a sub-5-minute exposure time of the SPME fiber in the pembrolizumab sample demonstrated ideal precision and yield. Building on this knowledge, a calibration curve was constructed utilizing 20 seconds of SPME sampling. The overall curve (3-80 ug/mL) was logarithmic (R2= 0.9845) with high precision and adequate yield. The linear portion of the curve (3-27 ug/mL, R2=0.9775) was below the range needed for in vivo applications, though still applicable for collected samples that can be diluted. Thus, fiber saturation still must be lowered by increasing their extraction capacity.
Conclusion
The new SPME sampling method showed linearity and reproducibility in the 3-27 ug/mL range, which is suitable for in vitro applications. Further optimization and validation of this ABS Plastic SPME method is still needed to create a method applicable in vivo. Future goals include further developing and validating the quantitative method for in vivo sampling in mice.
Keywords
Pembrolizumab, SPME, LC-MS/MS, TDM, ABS
Poster 31 Abstract
Analysis of Pembrolizumab in Biological Samples Using Sampling by ABS Plastic SPME and Quantitation by LC-MS/MS
Dylan Mattison, Michael Long, Eric Ng, Marcel Musteata
Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences
Presenting and Corresponding Author: Dylan Mattison, [email protected]
Purpose
This research aims to develop a method combining acrylonitrile butadiene styrene (ABS) plastic Solid Phase Microextraction (SPME) and Liquid-Chromatography Mass Spectroscopy (LC-MS/MS) techniques for the quantification of the anti-cancer, monoclonal antibody drug, pembrolizumab. Clinically, such a method would allow for therapeutic drug monitoring of pembrolizumab within blood and tumors, accessing the concentration of drug reaching the cancer site, and allowing for better dosing recommendations and more efficacious pembrolizumab treatment, while also demonstrating the first use of SPME for sampling proteins.
Methods
To test the overall effectiveness of various SPME approaches, calibration curves plotting the Amount of Extracted Pembrolizumab vs Amount of Pembrolizumab in Sample were created. These curves were analyzed for the SPME fiber yield, saturation, and precision. Additional experiments were done to manipulate certain materials or parameters of the method like oxidation, addition of coupling agents, and fiber thickness to observe how they may increase its robustness.
Results
Initially, various SPME materials were tested against one another. ABS plastic fibers were chosen for having the highest yield of those supports that still maintained reasonable precision (RSD<6%). However, those fibers became saturated at higher pembrolizumab levels, demonstrating the need for further modifications to increase the linear range. In one approach, a sub-5-minute exposure time of the SPME fiber in the pembrolizumab sample demonstrated ideal precision and yield. Building on this knowledge, a calibration curve was constructed utilizing 20 seconds of SPME sampling. The overall curve (3-80 ug/mL) was logarithmic (R2= 0.9845) with high precision and adequate yield. The linear portion of the curve (3-27 ug/mL, R2=0.9775) was below the range needed for in vivo applications, though still applicable for collected samples that can be diluted. Thus, fiber saturation still must be lowered by increasing their extraction capacity.
Conclusion
The new SPME sampling method showed linearity and reproducibility in the 3-27 ug/mL range, which is suitable for in vitro applications. Further optimization and validation of this ABS Plastic SPME method is still needed to create a method applicable in vivo. Future goals include further developing and validating the quantitative method for in vivo sampling in mice.
Keywords
Pembrolizumab, SPME, LC-MS/MS, TDM, ABS
