Partition coefficients charged liposome

Principal differences between bulk media water and membrane water partition coefficients are listed in Table 2. These differences are essentially based on the several orders of magnitude difference in surface-to-volume ratio. In the liposomal system, charges built up due to sorption of charged species can be electrically neutralised by counter-ions from the electrolyte (diffuse double... 

For the neutral form of 13 bases, again a very poor correlation between partitioning into octanol and liposomes was observed. The range found for the partition coefficients was 2.0 to 6.0 in octanol and +1.0 to < 5.0 in the liposomal system (-2 is the observable minimum according to the authors). Poor correlations were also found for the cationic forms of the bases (r2 = 0.49). Generally, the differences (log Poct.-log Psuv) for the neutral forms are smaller than the differences observed for the charged species. 

The larger partition coefficient into lipids is because only the neutral form can efficiently partition into octanol. Ordered phospholipid bilayers can, however, take up both forms neutral and charged. The influence of anionic and cationic charge on the ability of amphiphilic drugs to partition and bind to DPPC liposomes was investigat-... 

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