Test system for evaluating the compatibility of biologically active substances with copolymers

1. A liquid mixture comprising

a) 1,3-bis(pyrrolidon-1-yl)butane and

b) at least one compound of the formula I

in which

Q is CH 2 —Z, CH 2 —CH 2 —Z or CHZ—C 1 -C 4 -alkyl,

n is 0, 1, 2 or 3, and

the Z radicals are C 1 -C 20 -alkylcarbonyloxy, carboxy, C 1 -C 20 -alkyloxycarbonyl, C 2 -C 4 -hydroxyalkyloxycarbonyl, di(C 1 -C 4 -alkyl)amino-C 2 -C 4 -alkyloxycarbonyl or tri(C 1 -C 4 -al-kyl)ammonium-C 2 -C 4 -alkyloxycarbonyl.

2. The mixture as claimed in claim 1 , where component b) is 1,4-diacetoxybutane.

3. The mixture as claimed in claim 1 , in which components a) and b) are present in a ratio of from 10:1 to 1:10 by weight.

4. A test system for evaluating the compatibility of a biologically active substance with a copolymer which includes units of N-vinyl-pyrrolidone and of at least one ethylenic unsaturated monomer of the formula II

CH 2 ═CR—Z′  (II)

in which R is hydrogen or methyl, and Z′ has the meaning indicated in claim 1 for Z, where the test system includes a liquid mixture as claimed in claim 1 and at least one biologically active substance.

5. The test system as claimed in claim 4 , comprising from 10 to 70% by weight of biologically active substance.

6. The test system as claimed in claim 4 , additionally comprising at least one formulation aid.

7. A method for evaluating the compatibility of a biologically active substance with an N-vinylpyrrolidone copolymer which includes units of N-vinylpyrrolidone in a proportion by weight of X VP and units of at least one ethylenically unsaturated monomer of the formula II

CH 2 ═CR—Z′  (II)

in which R is hydrogen or methyl, Z′ is C 1 -C 20 -alkylcarbonyloxy, carboxyl, C 1 -C 20 -alkyloxycarbonyl, C 2 -C 4 -hydroxyalkyloxycarbonyl, di(C 1 -C 4 -alkyl)amino-C 2 -C 4 -alkyloxycarbonyl or tri(C 1 -C 4 -alkyl)ammonium-C 2 -C 4 -alkyloxycarbonyl, in a proportion by weight of X M , in which

a) a test solvent which comprises 1,3-bis-(pyrrolidon-1-yl)butane in a proportion by weight of X vp and a compound of the formula I in a proportion by weight of X M

in which Q is CH 2 —Z, CH 2 —CH 2 —Z or CHZ—C 1 -C 4 -alkyl, n is 0, 1, 2 or 3, the Z radicals are identical and correspond to the Z′ radical, is prepared,

b) the biologically active substance is brought into contact with the test solvent, and

c) the phase behavior of the mixture and/or solubility of the biologically active substance in the test solvent is determined.

8. The method as claimed in claim 7 , in which the phase behavior of the mixture is investigated visually, spectroscopically and/or thermoanalytically.

9. The method as claimed in claim 7 , in which the mixture of biologically active substance and test solvent is heated to a temperature of up to 140° C.