Good question: I'd have said yes, but don't know what the thermodynamics & kinetics are for the unfolding of BSA in PBS @ 37 degree long term: See [1] below for more info for BSA unfoldimng at higher temps 60 - 80 degrees:

[1] Kinetics of Thermal Denaturation and Aggregation of Bovine Serum Albumin, PLoS One. 2016; 11(4): e0153495. FREE From: Article Kinetics of Thermal Denaturation and Aggregation of Bovine S...

Thanks John Clarkson , I will read your suggestion.

KR Luis

I don't know what you mean by "BSA stability" but you might be able to determine the BSA concentration in your drug test samples and in control samples and then correct for their differences, if any.

The solution itself is pretty stable (can be stored at least a week), but there is a serious problem (especially, at 37˚C ) - bacterial contamination. These conditions are good for a lot of strains which can spoil the experiment. Ultrafiltration can help.

Good luck!

Dear Don, Thank you for the input. I’m trying to get an insight regarding the chemical stability of BSA in PBS, in particular references to any paper/book or published report that I can consult before going to the lab bench to confirm the information and actually perform the experiments. I’m designing the experimental setup/plan to assess the drug release (medium is PBS) from nano-particulate delivery systems involving BSA. Chemical stability will (most likely) impact physical stability as well as the drug release kinetics. Any hints?

Thanks again. KR Luis

Dear Denis Korneev , Thank you for your advice. We are already working under "sterile" conditions which includes ultra-filtration. Do you have, by any chance, a reference to the BSA chemical stability in PBS?

Thanks again. KR, Luis

Dear Luis, Thank you for clarifying. OK, I'm having a little trouble visualizing your experiment. My understanding is that you will be quantifying BSA in the drug-release medium (PBS). Do the nanoparticles and/or the encapsulated drug(s) contain BSA? Does the drug release medium (PBS) by itself contain BSA before drug-release?

Thank you, Don

Dear Don Kaiser , we plan to assess the BSA released (from the nanoparticles) to the PBS medium at 37°C/pH=7.4, over an unusually long period of time (7 to 10 days). A defined amount of the nanoparticulate system is dispersed in 100 mL (for instance) of the release medium (time=0) containing no BSA and afterwards 1 mL samples are withdrawn at predefined elapsed times (min, hours or days). The samples are processed to remove the nanoparticles (still containing non-released drug) from the medium containing the released drug. We are assessing the impact of the nanoparticles composition in the drug release kinetic.

It’s a simple and common type of experiment when chemical stability (of the analyte in the release medium) is not an issue. Depending on the stability we may have an analytical or experiment design problem to solve, a drug development problem, both or no problem whatsoever. I hope the scenario is a bit clear now.

Thank you, KR, Luis

Dear Luis F. Gouveia , sorry for my incorrect suggestion about bacterial contamination. Of course, it is not a big deal for a good pharmaceutical lab :)

I have seen a few papers about long term experiments with BSA. It is not so easy to remember them all now, but I have found one:

https://pdfs.semanticscholar.org/fd37/5e23b4b4726a4d7998b8f212b7c361336585.pdf

------------------------------------------------------------------------------------

BSA degradation under the above solution conditions was assessed initially by determining the level of native monomer after 28 days of incubation at 37C (Tab. 1). Under the conditions examined, BSA was most stable at pH 7 regardless of ionic strength and protein concentration since no significant loss in protein monomer was detected.

-------------------------------------------------------------------------------------------

Cheers,

Denis

Dear Luis, Thanks for clarifying. Your experiments sound really fun. I commend you for your concerns about BSA stability. I believe that in humans, albumin turnover time is about one month and I would think it would be the same for BSA? Your conditions are different than in the body of course but for BSA-release quantification, I can't imagine any problems. I think you will easily detect the albumin, even if it starts to break down. If your albumin is conjugated to a drug, it's likely to have entirely different stability and kinetics that will need to be determined.

Dear all,

Can i dissolve HSA in pbs? Please suggest me.

Thank you