Abstract: A method for separating particles in free-flow electrophoresis FFE includes conveying a separation medium using a dosage pump into a separation chamber; releasing the separation medium via outlets; applying an electrical field in the separation medium; coupling a particle to be separated with selectively defined charge labels for generating charge-modified particles which due to their selectively modified net surface charge display a different migratory behavior in FFE than non-charge-modified particles; adding a mixture of particles to be separated to the separation medium in the separation chamber by way of sample injection points; removing the particles separated using the separation medium by way of fractionation points; and collecting the fractions with the separated particles.

Abstract: A free-flow electrophoresis (FFE) apparatus and separation medium for separating particles therefore, includes a separation chamber with a dosage pump for conveying medium, electrodes for applying an electric field in the medium and sample injection points for adding a mixture of particles to be separated and fractionation points for removing the particles. Definable charge labels couple with the particles to form charge-modified particles which display with a different migratory behavior in FFE The apparatus includes focusing buffers between the separation medium and at least one electrode which has much higher electrical conductivity than the separation medium.

Abstract: Estrane and androstane derivatives of formula I ##STR1## wherein X is bromine, iodine, triphenyltin or trialkyltin of 1 to 6 carbon atoms per alkyl radical,Y represents two hydrogen atoms or methylene,Z represents two hydrogen atoms, oxo or alkylenedioxy of 2 to 6 carbon atoms andV is ethylene, vinylene, 1,3-propylene or cyclopropylene,R.sub.1 is hydrogen or a hydrocarbon radical of up to 8 hydrocarbon atoms, optionally interrupted by an oxa group or substituted by an oxo group,R.sub.2 is methyl or ethyl,R.sub.3 and R.sub.4 represent a carbon-carbon bond or R.sub.3 is hydrogen and R.sub.4 is hydrogen or methyl,.DELTA.symbolizes a 4(5)-double bond if Z signifies two hydrogen atoms or an oxo group; or a 5(6)-double bond or, for the estrane derivatives of formula I, also a 5(10)-double bond, if Z is alkylenedioxy,are pharmacologically effective substances or intermediates for preparation thereof.