3 results about "Reversed-Phase Liquid Chromatography" patented technology

This invention belongs to the field of synthetic biology and microbial engineering, and discloses a chemical-biological method for preparing the isopentenyl bibenzyl compound 2-isopentenyl-3,3',4',5-tetrahydroxybibenzyl (NPB-1575) which has anti-ischemic stroke activity. The specific disclosed method includes: (1) chemically synthesizing the substrate dihydropiperidine; (2) constructing an engineered Escherichia coli strain based on the isopentenyl utilization pathway, co-expressing hydroxyethylthiazol kinase, isopentenyl phosphokinase, isopentenyl pyrophosphate isomerase and specific isopentenyl transferase, and efficiently synthesizing the isopentenyl donor; (3) using this strain to catalyze dihydropiperidine in whole cells, the yield in a 200L fermenter can reach 2.54g / L, which is nearly 40 times higher than the existing method; (4) obtaining NPB-1575 with a purity >98.5% by macroporous adsorption resin and normal / reversed phase chromatography and recrystallization. This method uses readily available raw materials, involves simple steps, is environmentally friendly, and yields high purity, laying the foundation for the development of NPB-1575 as a new drug for ischemic stroke and showing significant application potential.

This invention discloses a method for determining ceftazidime and its formulation polymers, comprising the following steps: 1) preparing a system suitability solution; 2) preparing a reference solution; 3) preparing a test solution for ceftazidime for injection; 4) determination: injecting the system suitability solution, reference solution, and test solution into a liquid chromatograph, respectively, and performing determination using reversed-phase chromatography, wherein the mobile phase of the reversed-phase chromatography contains mobile phase A and mobile phase B, mobile phase A being an aqueous formic acid solution and mobile phase B being methanol. The chromatogram obtained by the method of this invention has a stable baseline, can detect multiple polymeric impurities of ceftazidime, and exhibits good separation of each impurity; the method of this invention has good specificity and system suitability, and its linearity, sensitivity, repeatability, intermediate precision, and robustness are all good; furthermore, the test solution and reference solution of this invention have high stability.

This invention relates to the field of pharmaceutical analysis technology and discloses a method for detecting the content of ezetimibe and rosuvastatin calcium tablets using a reversed-phase chromatography system. The method employs high-performance liquid chromatography (HPLC) with 0.1% trifluoroacetic acid solution as mobile phase A, acetonitrile as mobile phase B, and methanol as mobile phase C. Gradient elution is performed using an octadecylsilane-bonded silica column. The detection wavelength is 242 nm, and the injection volume is 10 μL. The content of ezetimibe and rosuvastatin calcium is calculated using the external standard method. This method can effectively separate the two main components from various degradation impurities, exhibiting good peak shape and excellent resolution. It meets the requirements for pharmaceutical quality control in terms of specificity, limit of quantitation, limit of detection, linear range, precision, accuracy, repeatability, and robustness. The system is stable and provides a reliable technical solution for the quality detection of ezetimibe and rosuvastatin calcium tablets.