[EvilGenius]

Hi there,

Does anyone know what the difference is between the hydrophilic - lipophilic balance (HLB) and the partition coefficient (P)?

I have already tried to google it...

Thanks

[Babcock_Hall]

I think you will need to use Google on each term separately, and then compare them for yourself.  There is quite a bit available on the hydrophilic lipophilic balance.  I suspect that you are probably interested in one particular partition coefficent, but perhaps you could tell us a bit more.
http://swiftcraftymonkey.blogspot.com/2009/09/hlb-or-hydrophilic-lipophilic-balance.html

[EvilGenius]

Hi there,

Thanks for your reply.

Out of interest, I studied a bit of surfactant chemistry. This is why I came across HLB. I have a lot of familiarity with the HLB.

More recently, I have been reading a bit about medicinal chemistry. I came across the term "partition coefficient" (p).

I can see there is a difference in calculation (p = [Non-ionised drug in organic phase]/[Non-ionised drug in aqueous phase]).

I just don't understand why it is necessary to have both p and HLB.

I may need to read more about "p" to get a better understanding. This is my first time coming across it.

Thanks

[Babcock_Hall]

I think that octanol/water is a common (I think it is the most common) partition coefficient that is used in medicinal chemistry.  You might ask yourself about permeability.