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Arbutin is the main active ingredient in many herbal medicinal products that have diuretic, antimicrobial, bactericidal, and antioxidant effects. Many of these products are mixtures of different herbal substances. Therefore, the approaches to quality control of HMPs can vary significantly. The aim of the study was to compare arbutin assay procedures used in quality control of arbutin-containing products. Materials and methods. Samples of the following HMPs were used in the study: monocomponent Bearberry Leaf and multicomponent Brusniver® (herbal mixture, powder). The test methods used were titrimetry, ultraviolet-visible spectrophotometry, and high-performance liquid chromatography (HPLC). Results. The authors compared five arbutin assay procedures described in the monographs and product files for arbutin-containing HMPs. Conclusions. It has been established that the analysed procedures cannot be used interchangeably as equivalent test methods; the limits for arbutin have to be established for each specific procedure. Iodometric titration is the most labour- and time-consuming method, and the determined titration endpoint is a subjective assessment. Spectrophotometric methods do not require the use of an arbutin reference standard, but they can give overestimated results as compared to the HPLC and titrimetry methods. HPLC methods are more selective, but they require the use of reference standards. The recommended test methods for HMP quality control are HPLC and visible spectrophotometry; the titrimetric method is recommended for replacement.

Papaverine hydrochloride products are used as anticonvulsants in routine medical practice. Most of the approved product specification files include thin-layer chromatography for assessment of product-related impurities and UV spectrophotometry for determination of active pharmaceutical ingredients. An HPLC assay is not used for determination of papaverine hydrochloride in drug dosage forms.The aim of the study was to develop an HPLC test method for determination of product-related impurities and for quantification of papaverine hydrochloride in solutions for injection, tablets, and rectal suppositories.Materials and methods: samples of the following Russian-made papaverine products were used in the study: Papaverine, solution for injection, 20 mg/mL; Papaverine, rectal suppositories, 20 mg; Papaverine, tablets, 40 mg. The Agilent 1260 Infinity II DAD System was used for the HPLC assay, and the Agilent 8453Е UV-Vis System was used for recording UV spectra. The determination of product-related impurities and the assay of active ingredients were performed simultaneously by HPLC using a reversed-phase column Kromasil 100-5-C18, 250×4.6 mm, 5 μm, the gradient elution mode, and detection at 238 nm. Papaverine Hydrochloride USP RS, 99% purity, and Noscapine EP CRS were used as reference standards.Results: the study demonstrated that determination of product-related impurities and assay of active ingredients in papaverine products can be performed simultaneously using HPLC.Conclusions: the authors proposed an HPLC test method for determination of active ingredients in papaverine products, which is aligned with the “consistent standardisation” principle and can be recommended for inclusion into draft monographs for papaverine products.

The process of harmonisation of Russian and foreign approaches and requirements in the field of medicines quality assurance calls for revision of quality control procedures included in various regulations and guidelines. The monograph FS.2.5.0062.18 “Hawthorn flowers” of the State Pharmacopoeia of the Russian Federation XIV edition includes a test procedure for determination of flavonoids by a chromatospectrophotometric method. This procedure does not take into account current scientific capabilities and has a number of shortcomings, therefore it was necessary to revise the existing test procedure and develop a new approach to the standardisation of the hawthorn flower herbal substance.The objectiveof the studywas to develop an assay method for standardisation and evaluation of hawthorn flower using high performance liquid chromatography (HPLC).Materials and methods:the study was performed using samples of hawthorn flowers by Russian manufacturers. Quercetin (USP RS) and Hyperoside (HWI, primary standard) were used as the reference standards. The HPLC analysis was performed using an Infinity II 1260 DAD LC system (Agilent), and the UV spectra were recorded on a Cary 100 Varian spectrophotometer. A TLC Visualizer (CAMAG) was used to obtain digital images of thin layer chromatography plates.Results:the authors developed an HPLC test procedure for quantitative determination of total flavonoids, expressed as hyperoside, in hawthorn flowers. The developed procedure gives reliable and reproducible results and is characterised by high sensitivity and selectivity. The results of quantitative determination of the total flavonoid content in hawthorn flowers were used to propose the standard for the total content of flavonoids, expressed as hyperoside, of “not less than 0.5%”.Conclusions:the developed assay method for determination of active pharmaceutical ingredients in hawthorn flower products by HPLC can be recommended for inclusion into the Assay part of the “Hawthorn Flowers” monograph of the State Pharmacopoeia of the Russian Federation.