Abstract: The present invention relates to a process for the preparation of mixed polyol-carboxylic acid esters having a molecular weight of greater than or equal to 200 g/mol and less than or equal to 1000 g/mol, wherein a polyol is reacted in an at least two-step reaction with different monocarboxylic acids in the form of monocarboxylic acids or of monocarboxylic acid anhydrides, wherein the different monocarboxylic acids are reacted with the polyol in the order of their reactivity in the esterification reaction, starting with the lowest reactivity, wherein the monocarboxylic acids with the lower reactivity are reacted at least partly as monocarboxylic acid anhydride and the monocarboxylic acid with the highest reactivity is reacted thereafter as monocarboxylic acid with the polyol. Furthermore, the present invention relates to the use of the process for the preparation of mixed polyol esters.

Abstract: Membrane module for testing active substances in cells with an interior chamber (2) which is limited by a lid (3), a bottom (4), and a side wall (5) and a system of first capillary membranes (6) and a system of second capillary membranes (11) located therein and possibly additional systems of capillary membranes, whereby the capillary membranes in interior chamber (2) are arranged in at least one flat layer parallel to bottom (4) and in interior chamber (2) in the extracapillary space a cell culture chamber is formed around the capillary membranes, whereby the capillary membranes have a lumen that can be filled with a fluid, are passing with at least one of its ends through the side wall (5) of interior chamber (2) and are embedded at this end separated by systems in a casting material (9, 10) so that interior chamber (2) is sealed fluid-tight from the outside, and whereby the capillary membranes of each system are in a fluid connection with their lumens with an inlet device (7) and/or an outlet device (8), a