What is the most appropriate way to approach scaling up your analytical method when transferring it to preparative chromatography scale?

Overview

In preparative chromatography there are three goals. How you balance these will dictate how you approach your scale up from analytical to preparative scale for large scale HPLC purifications.

Part 1: Optimizing Separation

In preparative HPLC there is a balance between purity, yield, and throughput, and often you must sacrifice one to achieve the other two. The three diagrams below show different outcomes depending on the purification objectives:

• Left: you could have a balanced triangle, where all three components are achieved, albeit none of these reach their maximum,
• Middle: you could prioritize purity and yield at the cost of longer sample processing times, or
• Right: you could prioritize sample processing speed and purity, sacrificing purification yield.

Before you begin you would want to consider:

• What is the required final purity?
• Is the desired final product a specific salt form, a solid or a solution?
• How can you balance processing time and yield?

Typically, with crude samples the impurities can lie close to the peak of interest. Although the desired resolution may be achieved analytically, it is important to ascertain, during the development process, how much of your sample you can load before resolution is lost. Shown below is an example of column screening for liraglutide where four stationary phases were screened under various conditions to ascertain optimal separation of impurities. Once you complete your screening you are able to select the most appropriate separation for scale up (covered in Part 2 - our next month's technical tip).

Kinetex™ C8

Kinetex C18

Kinetex Phenyl-Hexyl