Abstract: Shangtongning ointment is used for promoting blood circulation and removing blood stasis, reducing swelling and relieving pain. Used for acute soft tissue injuries such as sprained joints, muscle strain, ligament strain. Objective To establish a method for simultaneous determination of menthol and methyl salicylate in Shangtongning ointment by gas chromatography. Method Using n-pentadecane as internal standard, DB-WAX elastic quartz capillary column (30m × 0.32mm, 0.25μm), FID detector, nitrogen as carrier gas, column temperature of 130 ℃, detector temperature of 200 ℃, The split ratio is 12: 1. Results A total of 6 batches of samples were determined. Under this chromatographic condition, menthol, methyl salicylate, and internal standard substance n-pentadecane were well separated. The sample recovery rates of menthol and methyl salicylate were 101.52% (RSD = 2.66%) and 100.34% (RSD = 3.38%), respectively. Conclusion This method is sensitive, accurate and reproducible, and can be used to control the quality of the preparation. Acute soft tissue injuries such as meat strains and ligament injuries. There is no content determination item in the original standard. In order to better control the quality, a gas chromatography method was established for the determination of menthol and methyl salicylate in samples. Now reported as follows. 1 Instruments and reagents Agilent 6890N gas chromatograph, FID detector (US Hewlett-Packard Company). Menthol reference substance (0728-9304) and methyl salicylate reference substance (110708-200506) were purchased from China National Institute for the Control of Pharmaceutical and Biological Products. Shangtongning ointment was purchased from Henan Health Pharmaceutical Company (lot number 20060501, 20061001, 20061002) and Wuhan Changfeng Pharmaceutical Company (lot number 060303, 060304, 060401). 2 Methods and results 2.1 Chromatographic conditions Agilent 6890N gas chromatograph, hydrogen flame ionization detector (FID); DB-WAX elastic quartz capillary column (30m × 0.32mm, membrane thickness 0.25μm). Nitrogen flow rate is 30mL / min, air flow rate is 400mL / min; column temperature is 130 ℃; inlet temperature is 200 ℃, detector temperature is 200 ℃, split ratio is 12: 1. 2.2 Specific test Prepare a negative control sample lacking menthol and methyl salicylate raw materials according to the prescribed amount, and compare the chromatograms of the test solution, menthol and methyl salicylate reference solution, and negative control sample solution. Under the conditions, the peaks of menthol, methyl salicylate and other components in the sample can reach the baseline separation, and the negative control liquid chromatography peak does not interfere with the determination (see Figure 1). 2.3 Preparation of test solution Take 5 pieces of this product, cut it into small strips (0.5cm × 5 ～ 7cm), remove the lid liner, take about 1.5g, place it in a conical flask, and accurately weigh it. Precisely add 50mL of the internal standard solution, weigh it, weigh it, sonicate (power 300W, frequency 40kHz) for 15min, let it cool to room temperature, make up the lost weight with the internal standard solution, shake well, filter, take the filtrate Get it. 2.4 Determination of correction factor Take an appropriate amount of n-pentadecane, accurately weigh it, add ethyl acetate to make a solution containing 0.09mg per 1mL, as an internal standard solution. Another appropriate amount of menthol reference substance and methyl salicylate reference substance is accurately weighed, and the internal standard solution is added to make a solution containing 0.2mg and 0.15mg per 1mL, shake well, and 1μL is injected into the gas chromatograph and calculated Correction factor. 2.5 Investigation of linear relationship Precisely weigh the appropriate amount of menthol reference substance and methyl salicylate reference substance, add internal standard solution to dissolve and make a solution containing 1.909 and 1.414mg per 1mL, respectively, as a stock solution. Accurately measure 0.2, 0.4, 0.6, 1.0, 1.5, and 2.0 mL of the reference stock solution in a 10 mL volumetric flask, add the internal standard solution to the mark, and shake well. Accurately absorb 1μL of the above reference solution and inject it into the gas chromatograph, determine the peak area according to the above chromatographic conditions, with the concentration (mg / mL) as the abscissa, and the ratio of the peak area to the internal standard peak area as the ordinate, draw a standard curve and calculate Regression equation. The linear equation is: menthol Y = 9.3366X 0.0197, r2 = 0.9997; methyl salicylate Y = 5.9788X-0.0013, r2 = 0.9998. The results show that menthol and methyl salicylate have a good linear relationship in the range of 0.03818 ~ 0.3818mg / mL and 0.0283 ~ 0.283mg / mL, respectively. 2.6 Stability test Take the test solution of the same batch number (20061001), accurately draw 1μL, inject samples at certain intervals, measure, and investigate by peak area. Menthol RSD = 1.30%, methyl salicylate RSD = 1.37%, the results show that the test solution is basically stable within 15h, indicating that the method has good stability. 2.7 Repeatability test Take 6 copies of the same batch of Shangtongning ointment (lot number 20061001), according to the content determination method in parallel test to determine its content, the results of menthol content of 5.20mg / g, methyl salicylate content of 3.95mg / g. 2.8 Sample recovery test Weigh 6 samples of the same batch with known content (batch number 20061001, menthol content is 5.1975mg / g, methyl salicylate content is 3.9511mg / g) about 0.75g, accurately weighed, and add the appropriate amount of the reference substance , Prepare the test solution according to the method under "2.2", determine its content, and calculate the recovery rate. Results The average recovery of menthol was 101.52%, and the average recovery of methyl salicylate was 100.34%. See Table 1. 2.9 Sample determination Take 6 batches of this product and measure according to the above chromatographic conditions to calculate the content of menthol and methyl salicylate. The results are shown in Table 2. Table 1 Sample recovery test results 3 Discussion Reference [1-2] method was optimized for the determination of this product. In the treatment of the test solution, the internal standard substance n-pentadecane is added, so that the internal standard substance and the component to be tested undergo the same processing process, which can improve the accuracy of the measurement result. Compared with the external standard method, it has higher accuracy and easy operation. In the pretreatment process of the test solution, different extraction methods such as cold immersion, ultrasound and steam distillation were compared, different extraction solvents such as absolute ethanol, ethanol, ethyl acetate, and different ultrasonic times (5, 15, 30min) extraction efficiency, based on the extraction results, combined with the simplicity of the test operation, comprehensive considerations, to determine the final extraction conditions of this test. The test solution prepared by the steam distillation method is relatively pure, but the content is lower than the treatment method in this test, so it is not selected. The gas chromatography determination method established in this experiment is sensitive, accurate and reproducible, which improves the quality control of the preparation. Pet Collars & Leashes,Pet Collars,Pet Leashes,Dog Collars,Dog Leashes Ningbo Yinzhou Hengxi Winbate Household Product Manufacturer , https://www.winbatehousehold.com