Medicated syrups are aqueous solutions containing sugar and at least one water soluble active ingredient.
The sugar is mainly used to:
The concentration of sugar must approach but not quite reach the super-saturation point: the sugar concentration should be between 65 and 67% in weight. A lower percentage of sugar makes the syrup an excellent nutriment for yeast and other microorganisms. A sugar saturated syrup lead to crystallization of a part of the sugar under conditions of changing temperature.