Abstract: A process for preparing and purifying cyclic peptides having disulfide moieties in a two step processing operation including reverse phase chromatography which simplifies synthesis and reduces production costs, yet produces high, quality yield. The improved process is particularly useful for the preparation of vasopressin and oxytocin and their respective derivatives and analogs.

Abstract: A process for preparing and purifying cyclic peptides having disulfide moieties in a single processing operation which simplifies synthesis and reduces production costs, yet produces high, quality yield. Higher yields are obtained by isolating the desired cyclic compound through direct ion exchange chromatography as an integral part of the single process. The improved process is particularly useful for the preparation of vasopressin and oxytocin and their respective derivatives and analogs.

Abstract: An apparatus for pressing liquid out of suspensions containing liquid, comprising a screw feeder (5) adapted to feed the suspensions towards a dewatering zone (2) in which there are disposed two converging endless filter members (20, 21) adapted to be driven round a pair of back and front breaking rollers (18a, 18b). The pressing angle (.alpha.) between the filter members can be varied as can the speed of the filter members in relation to the material which is fed forwards in order to achieve an optimum flow resistance for each suspension. In certain cases, this can be very high. A worm wheel (13) is provided to prevent material from retreating in the screw thread (11).According to one form of embodiment, two or more dewatering zones are disposed in series one after the other, thus further increasing the possibilities for achieving optimum dewatering conditions.