Phenonip® can be added to the aqueous phase readily up to its limit of solubility.
The relatively low aqueous solubility of Phenonip® means that if the water content of the formulation is low, it may not be convenient to add the preservative directly to water during manufacture. Heating the water to 60 - 700C prior to Phenonip® addition will, in most instances, allow the appropriate quantity to be dissolved.
For aqueous systems which cannot be heated, Phenonip® can be incorporated by preparing a concentrate in a suitable solvent, e.g. propylene glycol, and stirring this concentrate into the water to give a final Phenonip® concentration below its maximum water solubility.
In emulsified systems, Phenonip® is readily dissolved in the liquid phase prior to emulsification although it is often good practice to divide the Phenonip® content between the aqueous and lipid phases during their preparation.
In surfactant and detergent based products Phenonip® can be dissolved in the surfactant prior to the addition of water and other ingredients.