Role of Surface Activity and Association in Biological Efficacy

Role of Surface Activity and Association in Biological Efficacy 

Several other examples may be quoted to illustrate the importance of surface activity of many drugs. Many drugs produce intralysosomal accumulation of phospholipids, which are observable as raultilamellar objects within the cell. Drugs implicated in phospholipidosis induction are often amphipathic compounds [20]. Interaction between the surfactant drug molecules and phospholipid renders the phospholipid resistant to degradation by lysosomal enzymes, resulting in their accumulation in cells. 

Many local anaesthetics have significant surface activity and it is tempting to correlate their surface activity to their action. However, one should not forget other important factors such as partitioning of the drug into the nerve membrane (a factor that depends on the pfCa) and the distribution of hydrophobic and cationic groups, which must be important for the appropriate disruption of nerve membrane function. 

The biological relevance of micelle formation by drug molecules is not as clear as their surface activity, since the drug is usually applied at concentrations well below 

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