METHOD FOR QUANTITATIVE DETERMINATION OF ACTIVE SUBSTANCES IN MEDICINAL PREPARATIONS BY IR SPECTROSCOPY Russian patent published in 2019 - IPC G01N21/35 

FIELD: chemistry.

SUBSTANCE: invention relates to analytical chemistry, specifically to a method for quantitative analysis of pharmaceutical preparations containing two active substances. Method for quantitative determination of active substances in medicinal preparations by infrared spectroscopy involves: grinding and mixing an original drug containing active substances A and B until homogeneous mixture 1 is obtained; analysis of obtained homogeneous mixture 1 by IR-spectroscopy to obtain spectrogram 1; mixing and interfusion 50 % of obtained homogeneous mixture 1 with active substance A in amount of (2.3–2.6) % of weight of homogeneous mixture 1 to obtain homogeneous mixture 2, analysis of obtained homogeneous mixture 2 by IR-spectroscopy to obtain spectrogram 2; mixing and interfusion homogeneous mixture 2 with active substance A in amount of (2.3–2.6) % of weight of homogeneous mixture 2 to obtain homogeneous mixture 3, analysis of obtained homogeneous mixture 3 by IR-spectroscopy to obtain spectrogram 3; mixing and interfusion homogeneous mixture 3 with active substance A in amount of (2.3–2.6) % of weight of homogeneous mixture 3 to obtain homogeneous mixture 4, analysis of obtained homogeneous mixture 4 by IR-spectroscopy to obtain spectrogram 4; mixing and interfusion homogeneous mixture 4 with active substance A in amount of (2.3–2.6) % of weight of homogeneous mixture 4 to obtain homogeneous mixture 5, analysis of obtained homogeneous mixture 5 by infrared spectroscopy to obtain spectrogram 5; mixing and interfusion homogeneous mixture 5 with active substance A in amount of (2.3–2.6) % of weight of homogeneous mixture 5 to obtain homogeneous mixture 6, analysis of obtained homogeneous mixture 6 by IR-spectroscopy to obtain spectrogram 6; mixing and interfusion 50 % of obtained homogeneous mixture 1 with active substance B in amount of (14.7–55.9) % of weight of homogeneous mixture 1 to obtain homogeneous mixture 7, analysis of obtained homogeneous mixture – method of infrared spectroscopy to obtain spectrogram 7; mixing and interfusion homogeneous mixture with active substance B in amount of (14.7–55.9) % of homogeneous mixture weight to produce homogeneous mixture 8, analysis of obtained homogeneous mixture 8 by infrared spectroscopy to obtain spectrogram 8; mixing and interfusion homogeneous mixture 8 with active substance B in amount of (14.7–55.9) % of weight of homogeneous mixture 8 to obtain homogeneous mixture 9, analysis of obtained homogeneous mixture 9 by IR-spectroscopy to obtain spectrogram 9; mixing and interfusion homogeneous mixture 9 with active substance B in amount of (14.7–55.9) % of weight of homogeneous mixture 9 to obtain homogeneous mixture 10, analysis of obtained homogeneous mixture 10 by IR-spectroscopy to obtain spectrogram 10; mixing and interfusion homogeneous mixture 10 with active substance B in amount of (14.7–55.9) % of weight of homogeneous mixture 10 to obtain homogeneous mixture 11, analysis of obtained homogeneous mixture 11 by IR-spectroscopy to obtain spectrogram 11; obtaining a calibration model of the original medicinal preparation from obtained spectrograms 1–11: selecting spectral sections corresponding to substances A and B, and recording the height change of the peaks depending on the concentration of substance A or B to obtain a calibration model of the original medicinal agent, milling and mixing of the analysed drug preparation containing the active substances A and B until obtaining homogeneous mixture 12, analysis of the obtained homogeneous mixture 12 by infrared spectroscopy to obtain spectrogram 12 and determination of concentrations of substances A and B of the analysed drug according to spectrogram 12, using a calibration model.

EFFECT: high accuracy and speed of measuring two active substances of the preparation.

3 cl, 2 dwg, 6 tbl