Biotenside esters and phosphatides with vitamin-D and vitamin-E compounds; processes for their preparation; spontaneously dispersible agents containing these compounds, and their use for the treatment of tumors

A spontaneously dispersible concentrate which forms a microemulsion in water comprising:

• 0.001 to 15% by weight of an ester or a combination of esters of a vitamin-D compound according to one of formulae (I) to (IV):
• ##STR15## wherein R.sup.1 is selected from the group consisting of a C.sub.1-32 alkyl carbonyloxy, a C.sub.2-32 alkenyl carbonyloxy, a C.sub.2-32 alkapolyene carbonyloxy, a group of formula (V):
• ##STR16## a group of formula (VI):
• ##STR17## wherein n is 1, 2, 3, 4 or 5 and R.sup.2 is a radical selected from the group consisting of ##STR18## 0to 40% by weight of a solvent or solvent mixture which is pharmaceutically acceptable and is a hydrotropic or coemulsifier;
• 0.001 to 90% by weight of a pharmaceutically acceptable surfactant or surfactant mixture;
• and
• optionally up to 10% by weight of a vitamin or provitamin;
• and optionally up to 10% by weight of a free acid.