Hello André,

there is a Python Package called MDPOW (https://github.com/Becksteinlab/MDPOW) this scripts can calc the Pow(water-octanol partition coefficient) and Pcw(water-cyclohexane partition coefficient) and the calculations are perfomed with GROMACS.

Dear Andre,

The Umbrella Sampling technique should generate sufficient data to reconstruct the profile of the so-called "Potential of Mean Force"(PMF), which demonstrates how the excess chemical potential of your solute is changing when it is moved from the bulk water to the bulk octanol phase. If your model system is large enough, the curve you obtain should possesses two plateaus, which correspond to the phases mentioned above. The difference between the levels of those two should give you the free energy of transfer between the two solvents.

I had the opportunity to do some work in this field, including calculations of partition coefficients. The results were recently published in the following article:

https://www.researchgate.net/publication/303866652_Transfer_of_Non-Ionic_Surfactants_across_the_Water-Oil_Interface_a_Molecular_Dynamics_Study

Best regards,

Article Transfer of Non-Ionic Surfactants across the Water-Oil Inter...

Thank you very much for the valuable comments. I also had the opportunity to do some work on the theme. I was only successful on doing the following work:

https://www.researchgate.net/publication/312472593_Prednisolone_adsorption_on_lung_surfactant_models_Insights_on_the_formation_of_nanoaggregates_monolayer_collapse_and_prednisolone_spreading?ev=prf_high

Please, read it and give me a feedback on any valuable concern about a possible mistake in the methodology.

I am also going to read your work and use the python package MDPOW. Thanks. 

Article Prednisolone adsorption on lung surfactant models: Insights ...

Hello Heitor, is it possible to use MDPOW with other force fields different than OPLS-AA? If so, may I use it with the coarse grained force field Martini? Thanks.

Hello Tsvetan Zahariev, I am having trouble to calculate the octanol-water partition coefficient of drugs using a very similar procedure used by you. I am still comparing the whole methodology, but I can not find what I am doing wrong. Can you find it? Thank you in advance.

Dear Heitor, Do you have the MDPOW manual? Thanks.

Dear Tsvetan Zahariev, we tried to do exactly the same you did in your paper, but it seems the calculation of the octanol-water partition coefficient does not work for the drugs that I am trying to calculate in my lab. The results are many zero numbers or Nam characters. Do you know what is going on? Has it happened with you? Thank you for your collaboration.

Dear Andre, yes, is possible to use other force field, about the manual, i dont have the manual, but in the MDPOW folder has tutorial how to use. sorry for the delay

Dear Heitor, I can not find the manual. Could you send It to me, please? Thanks.

There is a wiki on the website,  https://github.com/Becksteinlab/MDPOW/wiki/mdpow-scripts 

This may help you!