Antibiotic Drug Discovery: UPLC Analysis and Sample Preparation Challenges

In a recent interview, Schyler Odum, a fifth-year graduate student at UTHSC, shared valuable insights into his work in antibiotic drug discovery and the critical role of Ultra-High Performance Liquid Chromatography (UPLC) in his research. Odum's expertise sheds light on the importance of advanced analytical techniques and efficient sample preparation in the field of medicinal chemistry.

UPLC vs. HPLC: Key Differences

Odum's work primarily utilizes UPLC, which offers several advantages over traditional High-Performance Liquid Chromatography (HPLC):

1. Pressure Capabilities: UPLC operates at much higher pressures (up to 11,000 PSI) compared to HPLC, allowing for better resolution.

2. Sample Consumption: UPLC requires significantly less sample, often less than a milligram, compared to HPLC which typically needs milligrams for analysis.

3. Resolution: The higher pressure in UPLC results in much better resolution of sample components.

4. Sensitivity: UPLC can detect extremely small amounts of sample, with Odum humorously noting that "you just breathe on it or think about your sample and the sample well, and the machine's going to be able to detect that."

Sample Preparation Challenges

Odum highlighted a critical aspect of his work: the need for efficient sample preparation, particularly in drying down samples for UPLC analysis. He emphasized that upgrading their nitrogen blowing apparatus would significantly benefit their UPLC work:

1. Solvent Compatibility: Samples from normal phase chromatography often contain solvents like DCM, methanol, or ethyl acetate, which are not always compatible with the UPLC system.

2. Sample Crashing: Incompatible solvents can cause samples to crash out in the UPLC lines, leading to overpressure issues and pump failures.

3. Time-Consuming Process: The current process requires drying down each sample completely and then re-suspending it in UPLC-compatible solvents like methanol or acetonitrile/water mixtures.

4. Equipment Limitations: Odum mentioned their current nitrogen blower is outdated, describing it as "from the sixties" and inconsistent in performance.

Improving Sample Preparation

Odum suggested that upgrading their equipment, particularly the nitrogen blower, could significantly improve their sample preparation process:

1. High-Throughput Processing: A modern nitrogen blower could allow for faster and more efficient sample drying.

2. Consistency: An upgraded system would provide more reliable and consistent nitrogen flow, addressing issues with their current equipment.

3. Noise Reduction: A newer system could potentially reduce the noise levels in the lab environment.

Additional Research Challenges

Odum also shared other challenges in his antibiotic drug discovery work:

1. Large Molecular Weight: The antibiotics Odum works with have a molecular weight of about 1500 amu, which is unusually large for drug compounds.

2. Complex Synthesis: The process involves an 18-step synthesis, requiring multiple solvents and chromatography steps.

3. NMR Resolution: Proving the exact structure of these large molecules through NMR is particularly challenging.

Importance of Antibiotic Research

Odum emphasized the critical need for continued support and funding in antibiotic drug discovery:

1. Lack of Profit Incentive: Big pharmaceutical companies often avoid antibiotic research due to limited profit potential.

2. Academic Focus: Much of the current antibiotic research is left to academic institutions.

3. Growing Resistance: Bacteria are developing resistance to currently used antibiotics, necessitating ongoing research.

4. Comorbidity Factor: Infections and sepsis are often overlooked comorbidities in other diseases, highlighting the importance of antibiotic research.

Conferences and Networking

Odum mentioned the Gordon Research Conferences as a key platform for presenting antibiotic drug discovery work:

1. Annual Conference: Held in New Hampshire, focusing on antibiotic drug discovery.

2. Accessibility: The conference often provides funding support, making it accessible for academic institutions.

3. Diverse Focus: Additional conferences cover gram-negative, tuberculosis, and NTM (Nontuberculous Mycobacteria) research.

In conclusion, Odum's insights underscore the importance of both advanced analytical techniques like UPLC and efficient sample preparation methods in antibiotic drug discovery. While UPLC offers significant advantages, its full potential can only be realized when coupled with effective sample preparation techniques. Investing in modern sample preparation equipment can greatly enhance the efficiency and accuracy of UPLC analysis, ultimately contributing to more rapid and effective antibiotic drug discovery processes.