1 Introduction
Because some drugs, especially new synthetic drugs, have very little optical rotation when the sample has a wavelength of 589 nm under the standard sodium light source, the US Pharmacopoeia, Japanese Pharmacopoeia and European Pharmacopoeia have selected different optically active drugs The wavelength of the light source is measured for its optical rotation. Therefore, in order to usually equip high-speed polarimeters with multiple wavelengths to detect the specific optical rotation of drugs.
2. Experiment preparation
2.1 Test equipment: Yidian Wuguang SGW ® -537 automatic (high-speed, multi-wavelength) polarimeter, SGW ® -100K temperature-controlled test tube , precision balance (1/10,000), 100 mL volumetric flask
2.2 Experimental reagents:
1) Ertapenem (antibiotic drug)
2) Sulfachloropyridazine Sodium (antibiotic drug)
3) Iopamidol (injection)
4) Finasteride (hormone drug)
5) Supporting solvents for various drugs
3 Experimental steps
3.1 Sample test
1) Weigh a certain amount of sample according to the requirements of USP, ESP, and JSP Pharmacopoeia, first dissolve it with a small amount of solvent, then transfer it to a 100mL volumetric flask, add solvent to the marking line of the volumetric flask, and shake well for later use.
2) Turn on the SGW®-537 high-speed polarimeter, select the corresponding light source wavelength, and warm up the instrument for 5-10 minutes .
3) Change the test mode of the instrument to the specific rotation mode, set the concentration to the concentration of the configured sample, and set the length of the test tube to 100 mm.
4) First inject the blank solvent into the SGW ® -100K temperature-controlled test tube, put it into the sample chamber of the instrument, and click to clear eliminate the influence of the solvent.
5) Take out the temperature-controlled test tube, pour out the blank solvent, rinse the test tube with the prepared sample for 2-3 times, and then add the sample to the temperature-controlled test tube with a syringe.
6) Put the sample-filled test tube into the sample chamber, insert the temperature measuring probe into the thermostatic test tube, set the instrument control temperature to 25°C, turn on the temperature control button, and start the temperature control. After the temperature of the sample is stable, click the test button, and the instrument will automatically read the specific rotation of the sample.
3.2 Sample calculation
Calculation formula:
Where: α: Optical rotation, [a] D 25 : Specific optical rotation constant at 25°C, c: Mass concentration g/ml, L: Optical rotation tube length dm
4 Results and discussion
4.1 Test interface
4.2 Applications
4.3 Instrument introduction
SGW®-537 is equipped with two wavelengths of 546 and 589nm as standard, and 365, 405, 436, 578, 633nm and other wavelengths are optional . The instrument adopts a digital platform, which ensures its accuracy, repeatability and reliability, improves the response speed of the test sample, realizes high-speed measurement, shortens the sample measurement time, and its technical indicators have reached the international high-end level in an all-round way. The instrument complies with the relevant requirements , including user classification management, electronic signature, password management, network transmission, data protection and traceability and other functions, a large database, data can be saved, transmitted, printed and Traceability, users can define pre-stored common measurement methods by themselves.
