On the solubilization properties of surfactant-polymer complexes.

Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) affect the solubilization properties of sodium dodecyl sulphate (SDS). When these polymers are added to SDS solution, its solubilization power for riboflavin, khellin and propyl p-hydroxybenzoate is markedly decreased. In case of riboflavin and khellin, the polymer effect is more pronounced at high surfactant concentrations; for propyl p-hydroxybenzoate, the polymer effect is inversely proportional to the surfactant concentration. On the other hand, the solubilization power of SDS towards methyl and butyl p-hydroxybenzoate is greatly enhanced by PEG or PVP. In case of methyl p-hydroxybenzoate the effect of PEG is more pronounced at high surfactant concentrations; the effect of PVP is not significantly dependent on the surfactant concentration. For butyl p-hydroxybenzoate, the polymer effect decreases markedly with increasing surfactant concentration.