Can pH of a His buffer change during lyophilization?

In summary, a monoclonal antibody (mAb) with a protein concentration of 50mg/ml and an isoelectric point (PI) of 7.5 was lyophilized using a 10mM His buffer with a pH of 6.2. Upon reconstitution, the pH was measured to be 6.5. The poster is wondering if anyone can explain this small pH change, as they believe His buffers are less susceptible to pH changes during lyophilization compared to phosphate buffers. They also mention that the term mAb likely refers to monoclonal antibody for average readers of the forum. However, to fully understand the situation, more information is needed such as the specific composition of the His buffer used.
  • #1
Dhh1994
1
0
We lyophilized 50mg/ml mAb with PI of 7.5 in a 10mM His buffer pH 6.2. Upon reconstitution the pH is 6.5. Does anyone have an explanation for this? I am under the impression His is much less susceptible to pH change during lyophilization as opposed to something like a phosphate buffer. Thanks.
 
Chemistry news on Phys.org
  • #2
I cannot answer from direct experience or knowledge. A quick look showed that there is quite a lot of literature on stability and lyophilisation of proteins, naturally. I would think that this is a small pH change is not a worry in itself. For average readers of this forum, mAb probably means monoclonal antibody.

To attempt to reason about it (no promise) it is not enough to tell us ‘His’ (histidine) buffer. You would have to tell us how it is made up. E.g. whetherstarting with histidine or histidine hydrochloride or other salt, and brought to pH with what?
 
Last edited:
  • Like
Likes jim mcnamara

1. Can the pH of a His buffer change during lyophilization?

Yes, the pH of a His buffer can change during lyophilization. This is because lyophilization involves removing water from a solution, which can also affect the concentration of the buffer components and ultimately the pH.

2. How much can the pH change during lyophilization?

The pH change during lyophilization can vary depending on the specific buffer composition and lyophilization conditions. In general, the pH can shift by up to 1-2 units during the process.

3. Will the change in pH affect the stability of the His buffer?

Yes, a significant change in pH during lyophilization can negatively impact the stability of the His buffer. This is because changes in pH can disrupt the delicate balance of interactions between buffer components, potentially leading to protein degradation or aggregation.

4. Can the pH change be prevented during lyophilization?

Yes, there are steps that can be taken to minimize the pH change during lyophilization. These include adjusting the buffer composition and pH prior to lyophilization, using stabilizing additives, and controlling the lyophilization process parameters.

5. How can the pH change during lyophilization be measured?

The pH change during lyophilization can be measured using a pH meter or pH indicator strips before and after the process. It is important to note that the accuracy of these measurements may be affected by the presence of other substances in the buffer solution.

Similar threads

Titration of amino acid with strong base
    • Biology and Chemistry Homework Help
Replies
16
Views
3K
Can strong acids and salts be used to create a pH 0.5 buffer?
    • Biology and Chemistry Homework Help
Replies
2
Views
4K

Hot Threads

Recent Insights

Back
Top