1. Field of the Invention
This invention relates to compositions for suppository bases having a good emulsifying effect for water, aqueous active-principle solutions, and polar active principles.
2. Statement of Related Art
Suppositories are cylindrical or slightly oval plugs of a composition fusible at body temperature in which medicaments are dissolved, dispersed or emulsified and which are intended for the application of those medicaments in the rectum of human beings.
Accordingly, suppositories consist essentially of a suppository base and active principles. The suppository base may contain certain auxiliaries which improve the viscosity, processability and stability of the base and the suppositories produced therefrom or which serve to improve the distribution of the active principles in suppositories and the adsorption of the active principles in the rectum. Water-insoluble fats are largely used as suppository bases. However, water-soluble compositions based on polyethylene glycols are also known, although they are of only limited importance due to their incompatibility with many active principles, their hygroscopicity and the resulting irritant effect on mucous membrane, and their tendency towards subsequent hardening. Finally, water-dispersible compositions based on certain nonionic surface-active ethylene oxide adducts are also known, although they have not acquired any commercial significance for similar reasons. However, a certain significance has been acquired by the so-called "hydrophilic fat bases", i.e. mixtures of lipophilic fats and certain nonionic emulsifiers.
However, known suppository bases based on lipophilic fats and also known "hydrophilic" suppository bases are unsuitable for the problem-free and stable incorporation of aqueous active-principle preparations or highly polar active principles, such as for example phenols, glycerol, sugar, in the often very large quantities required. Instead, separation frequently occurs in the cast suppositories. As a result, inhomogeneous, friable or fragile suppositories are obtained, giving rise to considerable problems in production and in use.