Solute disposition in emulsion systems

The use of emulsions in medicine demands a knowledge of the distribution of added agents to the formulation. Flavouring agents, preservatives, stabilizers and, of course, therapeutically active substances are added to emulsion formulations and are distributed at equilibrium between the continuous phase and the disperse 

Many preservatives are weak acids which ionize in the aqueous phase, 

The following treatment has been given by Shimamoto and Mima [199]. If the volume of the aqueous phase is the amount of ionized compound in the aqueous phase is given by 

In a simple two-phase dispersion of oil and water the undissociated molecules partition such that the partition coefficient, P, is defined as 

Binding of the preservative with non-ionic surfactant micelles has been represented [199] by an equation of the form  

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