Abstract: Compound Yikangning Tablets is a drug used to balance and regulate the nervous system. It is clinically used to treat menopausal syndrome, neurasthenia, and autonomic dysfunction. Its main components are procaine hydrochloride and vitamin B6. Shandong The provincial drug standard adopts the colorimetric method to determine the content of the two components, which is tedious and time-consuming. Another report has a second derivative spectrophotometry and a new solution to the simultaneous equations. We use dual-wavelength ratio spectroscopy to determine the content of the two components simultaneously Eliminate the interference of coexisting components, easy and fast operation, accurate results and good reproducibility.
Objective: To establish a dual-wavelength ratio spectrometric method for procaine hydrochloride and vitamin B6 in compound Yikangning tablets. Method: Draw the ratio spectrum of procaine hydrochloride and vitamin B6, and select the peak or valley point as the measurement wavelength Effectively eliminate the interference of coexisting components to achieve accurate determination of the measured components. Results: Under the selected experimental conditions, procaine hydrochloride and vitamin B6 have a good linear relationship in the range of 5.0 to 50.0 mg / L. The average recovery rates were 99.5%, 98.3% and relative standard deviation (RSD) were 1.2% and 0.8%, respectively. Conclusion: The method is simple, fast, reproducible, and the results are satisfactory.
1 Materials and methods
1.1 Materials
Shimadzu UV2201 automatic ultraviolet spectrophotometer; 1 / 100,000 electronic balance. Procaine hydrochloride, vitamin B6 reference substance (provided by Hebei Provincial Institute of Drug Control, dried at 105 ℃ to constant weight), the solvent is 0.1 mol / L Hydrochloric acid (hereinafter referred to as solvent), other reagents are analytically pure, compound Yikangning tablets (prepared by our pharmacy room).
1.2 Method
1.2.1 Basic principle In a compound drug containing a and b, if the two components obey Lambert's law in the entire wavelength range, the absorption spectrum of the mixed component can be expressed as: Aλi = KaλiCa KbλiCb①Aλi is the mixture in λi Absorbance at the location; Kaλi, Kbλi is the absorption coefficient of a, b at the wavelength λi; Ca, Cb is the concentration of a and b in the mixture. If b is the interference component, use the standard concentration of Cb ′ interference at the corresponding wavelength Component absorption spectrum removal ①Formula: Aλi 〖〗 KbλiCb ′ = Kaλi 〖〗 Kbλi? Ca 〖〗 Cb ′ Cb 〖〗 Cb′②
②The formula is the ratio spectrum of the mixture relative to the b component with the concentration of Cb ′. It can be seen that in the mixture, the contribution of the b component (any concentration) contrast value spectrum is a set of straight lines parallel to the wavelength axis at any wavelength The absorbance ratios R at all are equal, which is Cb / Cb ′. Therefore, two suitable wavelengths can be selected to measure ΔR, eliminate the interference of b, and quantify a, that is: ΔR = R2-R1 = (Kaλ2 〖〗 Kbλ2 -Kaλ1 〖〗 Kbλ1) 1 〖〗 Cb ′? Ca = K? Ca③Similarly, if a is regarded as the interference component and b is the measured component, the ratio spectrum of the mixture relative to a (Ca ′) can be obtained. b Quantify.
1.2.2 Preparation of reference substance stock solution Precisely weigh procaine hydrochloride 116.95 mg, dissolve in solvent and dilute to 100 mL volumetric flask, shake well, accurately draw 10 mL of the solution into 100 mL volumetric flask, use Dilute the solvent to the mark and shake well to obtain the procaine hydrochloride stock solution. â‘ Accurately weigh 118.23 mg of vitamin B6 reference substance, and prepare the vitamin B6 stock solution in the same way.
1.2.3 Drawing of ratio spectrum and selection of measurement wavelength Precisely absorb appropriate amount of reference stock solutions ①and ②, put them into 10 mL volumetric flasks respectively, dilute with solvent to constant volume and shake well, using solvent as reference, at 400 ～ 200 nm Scan to obtain the ultraviolet absorption spectra of procaine hydrochloride and vitamin B6 (Fig 1). Measure the absorbance (A) of each solution at a wavelength interval of 217.7 ~ 300.0 nm at intervals of about 1.2 nm, and calculate the procaine hydrochloride at each wavelength For the ratio Rp of the absorbance of vitamin B6, plot Rp against λ to obtain the ratio spectrum of procaine hydrochloride; similarly, calculate the ratio RV of the absorbance of vitamin B6 to procaine hydrochloride at each wavelength, and plot RV versus λ , Get the ratio spectrum of vitamin B6 (Fig 2). From Fig 2, it is known that the ratio spectrum of procaine hydrochloride has the maximum peak at the wavelength of 232.2 nm, and the minimum valley value of vitamin B6; and the ratio spectrum of vitamin B6 is at 292.7 nm There is a maximum peak at the wavelength, and procaine hydrochloride has the minimum valley. After selection, 232.2 nm and 292.7 nm are determined as the measurement wavelength.
1.2.4 Drawing the working curve Precisely absorb the reference stock solution â‘ 1.04 mL and the reference stock solution â‘¡ 1.00 mL, put them into 10 mL volumetric flasks respectively, shake with a constant volume of solvent, as the standard contrast solution. At 232.2 nm and 292.7 Determine the A value at nm. Accurately absorb the appropriate amount of the reference stock solutions â‘ and â‘¡, dilute with a solvent to a constant volume and shake well. Prepare a series of mixed standard solutions containing procaine hydrochloride and vitamin B6 at 232.2 nm and 292.7 nm respectively Measure A value, calculate â–³ R according to formula â‘¢, and use â–³ R to establish regression equation for C as:
Procaine hydrochloride: △ Rp = 0.2906C 0.07867 r = 0.9974 Vitamin B6: △ RV = 0.5986C 0.1696 r = 0.9998 where ΔRp = RP 232.2 nm-RP 292.7 nmRp232.2 nm = A232.2 nm〗 〖0.137RP292. 7 nm = A292.7 nm 〖〗 0.497 ΔRV = RV 292.7 nm-RV 232.2 nmRV232.2 nm = A232.2 nm 〖〗 0.515RV292.7 nm = A292.7 nm 〖〗 0.065
2 results
2.1 Recovery rate experiment Prepare the simulated tablet powder according to the prescription ratio, accurately weigh the appropriate amount of solvent and dissolve it, and set it in a 100 mL volumetric flask. Shake and filter. Accurately draw the continuous filtrate 10 mL into the 100 mL volumetric flask and add the solvent. Dilute to constant volume and shake to prepare a simulated sample stock solution. Accurately absorb the appropriate amount of the stock solution into a 10 mL volumetric flask, add solvent to dilute to constant volume and shake to prepare a simulated sample containing procaine hydrochloride and vitamin B6 For a series of mixed solutions, measure the A value at 232.2 nm and 292.7 nm, calculate â–³ RP and â–³ RV, substitute the linear regression equation, calculate the concentrations of procaine hydrochloride and vitamin B6, and then calculate the recovery rate The average recovery and relative standard deviation of caine and vitamin B6 were 99.5%, 1.2%, 98.3%, and 0.8% (Tab 1).
Table 1 Recovery rates of procaine hydrochloride and vitamin B6 (omitted)
2.2 Determination of samples Take 10 compound Yikangning tablets, remove sugar coating, accurately weigh out, find the average tablet quality, grind finely. Accurately weigh the appropriate amount of its fine powder (about equivalent to procaine hydrochloride 140 mg and vitamin B6 40 mg ), After dissolving with a solvent, dilute to a 100 mL volumetric flask, shake and filter; accurately draw the continuous filtrate 10 mL into a 100 mL volumetric flask, add solvent to dilute to a constant volume and shake to obtain a sample solution. Accurately draw the sample Appropriate amount of solution to a 10 mL volumetric flask, dilute with solvent to constant volume and shake well, measure the A value at the wavelengths of 232.2 nm and 292.7 nm, calculate â–³ Rp and â–³ RV, substitute the linear regression equation, calculate procaine hydrochloride and vitamins The marked content of B6 (Tab 2). Table 2 Sample measurement results (omitted)
3 Discussion
3.1 Selection of the measurement wavelength To effectively improve the sensitivity and accuracy of the method, the peak of the ratio spectrum (corresponding to the other component is valley) should be selected for the measurement wavelength. The ratio spectrum of procaine hydrochloride has a maximum peak at 232.2 nm The ratio spectrum of vitamin B6 has a minimum valley at this wavelength; procaine hydrochloride has a minimum valley at 292.7 nm, and vitamin B6 has a maximum peak. Therefore, 232.2 nm and 292.7 nm are determined as the measurement wavelength.
3.2 Conditions for using ratio spectroscopy For two-component compound drugs, the ideal ratio spectrum of the tested component should have at least one peak and one valley. Select the two wavelengths with the largest peaks and valleys as the measurement wavelengths to improve the sensitivity and accuracy of the method Degree; in the ordinary spectrum, the absorption curve of the two components has at least three intersections, and there are fewer drugs that can meet this condition. In actual work, if the ratio spectrum has only one peak or a valley, the absorption curve of the ordinary spectrum is only Two intersection points, in this case, the wavelength at the peak or valley can be used as a measurement wavelength, and another wavelength can be selected as the measurement wavelength outside the peak or valley. Use this method.
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