Separation and purification of ascomycin by a combined method of macroporous adsorption resin - reversed-phase polymer chromatography

Ascomycin plays an important role in the treatment of various autoimmune diseases and skin diseases; its application prospects in the pharmaceutical market are promising. As an intermediate of pimecrolimus, separating and purifying high-purity ascomycin is a key step in producing high-quality medicines. Moreover, ascomycin and its key impurities have similar structures, which makes the separation and purification process very challenging. Therefore, this study developed a new separation and purification system that combines the synergistic effects of reversed-phase polymer resin and macroporous adsorption resin to provide a novel separation and preparation process. In the static adsorption stage, HZ-816 was chosen as the optimal resin, and used Lagergren's second-order kinetic and the Temkin isotherm model as the best adsorption models; the adsorption process was spontaneous, exothermic, and multi-layer adsorption. To achieve optimal purification, we used 0.5 mg/mL ascomycin, a 4 BV/h flow rate, and a sample volume of 110 BV. The eluent was 70 % ethanol, with a flow rate of 2 BV/h. The obtained purity was 82.07 %, and the recovery rate was 62.68 %. During the reversed-phase polymer chromatography stage, by optimizing parameters such as the elution flow rate and loading quantity, the purity was increased to 98.55 %, with a recovery rate of 85.87 % and an elution rate of 95.54 %. The yield was 53.82 %. Through the optimization of experimental procedures and material selection, this study has laid a solid performance foundation for subsequent cost-effective, highly efficient, and sustainable applications, providing a reference for the technological advancement of the ascomycin separation and purification industry.