Chromatography Forum

Hi,
How can I calculate ''pH partition coefficient'' for bulk solution of lyophilized powder.

Thank you

Or how can I provided pH partition coefficent for both our and reference product.

I'm not quite sure what you are looking for here. I know what pH is, and I know what a partition coefficient is, but the combination is new to me (and doesn't show up in a Google search). Can you give more guidance on what you are trying to do?

Perhaps you're referring to pKa??

pH is usually an aqueous phenomena. It is the -ve logarithm of the hydronium ion activity (concentration). Why then are you looking for a pH potential in a lyophilized powder which has a typical moisture around 1-2%?

''The biowaiver is required based on the Reflexion paper on the pharmaceutical development of intravenous medicinal products containing active substances solubilised in micellar systems, because the test product and reference product have identical formulations. Based on the comparative studies performed on micelle characterisation the biowaiver is not sufficiently justified. Therefore, comparative in vitro studies between the test product and the reference product should be submitted.
aa)Information on the pH solubility, pH partition coefficient and pH stability profiles.''

This is authority question. We'll tested (pH,assay and nano-size) pH solubility and pH stability profile at lower and upper pH specification limit for bulk solution. Not lyophilize powder. But I can't understand pH partition coefficient.

Thank you

Hi Tubish81,

Is this what you mean by pH partition coefficient?

https://pubs.acs.org/doi/abs/10.1021/acs.iecr.6b02040

And, is this RefleXion?

https://www.reflexion.com/

Note, we will not know as much as you do about what you are interested in learning. The more you help us, the better we can help you.

''
aa)Information on the pH solubility, pH partition coefficient and pH stability profiles.''

Sounds to me like information about how solubility, partition coefficient and stability of your API are dependent on pH.

And it should read "Reflection paper..." not "Reflexion"

http://www.ema.europa.eu/docs/en_GB/doc ... 124410.pdf