In recent years, glycopeptide antibiotics have been widely used to treat severe bacterial infections. The long-term use of first-generation antibiotics of this group (vancomycin, teicoplanin) has contributed to the emergence of bacteria resistant to them. The problem of resistance has motivated the development of three new glycopeptide antibiotics: dalbavancin, telavancin, and oritavancin. The aim of this study was to consolidate and analyse the data from literature and current quality standards related to glycopeptide antibiotics. The article presents basic information about the discovery of glycopeptide antibiotics of natural origin (vancomycin, teicoplanin) and their derivatives (telavancin, oritavancin, dalbavancin). It briefly characterises the structures of the glycopeptide antibiotics under consideration and describes their main properties, application, and distribution in the pharmaceutical market. The article also gives information on the spectra of antibacterial activity of vancomycin, teicoplanin, and their semi-synthetic derivatives. It considers approaches to vancomycin and teicoplanin standardisation and covers the main requirements of leading pharmacopoeias for the quality of vancomycin, teicoplanin, and the corresponding medicinal products. According to the study results, glycopeptide antibiotics are still widely prescribed because of their high effectiveness in diseases caused by Gram-positive bacteria. However, at present, leading pharmacopoeias have developed and implemented quality standards only for two antibiotics of the group: vancomycin and teicoplanin. According to the results of literature consolidation, further modification of glycopeptide antibiotics is aimed at creating compounds characterised by prolonged action and greater effectiveness against pathogenic microorganisms. Thus, the attention of researchers should be directed to further standardisation of the newest derivatives of glycopeptide antibiotics: telavancin, oritavancin, and dalbavancin.

A method for the quantitative determination of streptomycin sulfate in medicines by the turbidimetric method has been developedand validated. Based on the results of the experiments, it was found that the metrological characteristics of such validation parameters of the method as linearity, precision, and correctness do not exceed the validation criteria. Linearity was noted in the range of streptomycin concentrations from 3.75 to 8.43 μg/ml. The results of validation tests of the method for the quantitative determination of streptomycin indicate the prospects and feasibility of introducing the turbidimetric method into the domestic system for standardization and quality assessment of aminoglycoside antibiotics.

The culture media quality, which depends to a large extent on growth promotion properties, determines the reliability and accuracy of test results obtained by microbiological methods. The procedure for culture media preparation is quite labourconsuming and includes several stages: successive dissolution of components exactly as specified in the recipe (qualitative and quantitative composition), sterilisation, adjusting the pH of the medium, and testing of growth promotion properties—therefore it is important to demonstrate the stability of each particular culture medium.The aim of the study was to evaluate growth promotion properties of the culture media prepared in the laboratory from a dry mixture, and to assess their stability during long-term storage.Materials and methods: stability testing was performed for fluid thioglycollate medium (FTM) and soybean-casein digest broth (SCD) prepared in the laboratory. FTM growth promotion properties were tested  using the following test microorganisms: Bacillus subtilis ATCC 6633,  Clostridium sporogenes ATCC 19404, Pseudomonas aeruginosa ATCC 9027,  Staphylococcus aureus ATCC 6538. SCD growth promotion properties were  tested using: Aspergillus brasiliensis ATCC 16404, Candida albicans ATCC  10231, Bacillus subtilis ATCC 6633. The stability study was carried out for 6  months, assessing changes in appearance and growth promotion properties. The test media were stored at room temperature and in a refrigerator at 2–8 °C.Results: no growth of the anaerobic microorganism Clostridium sporogenes was observed in FTM after 3 months, regardless of storage conditions. Later on, there was no growth of the gram-positive microorganisms Bacillus subtilis and Staphylococcus aureus, which are more sensitive to the storage conditions than Pseudomonas aeruginosa. The growth promotion properties of the SCD prepared in the laboratory did not change during 6 months of storage.Conclusions: FTM prepared from a dry mixture remains stable and retains its growth promotion properties for no more than two months when stored in a refrigerator at 2–8 °C. SCD can remain stable for 6 months, both at room temperature and when stored in the refrigerator.

Chromatographic methods for the analysis of antibiotic degradation products are widely used to evaluate the quality of medicines. Natural multicomponent antibiotics, such as capreomycin, are the most challenging compounds in terms of developing analytical procedures for related substances. Capreomycin sulfate monographs of the leading pharmacopoeias do not contain specifications for related substances. The key requirement concerns the sum of the main components of capreomycin calculated by normalising the peak areas in the test solution chromatogram. Therefore, it is important to develop an analytical procedure for determining not only the main components but also related substances of capreomycin.The aim of the study was to develop an analytical procedure for determining both the main components (IA, IB, IIA, and IIB) and related substances of capreomycin by ion-pair ultra-high-performance liquid chromatography (UHPLC).Materials and methods. This study examined capreomycin sulfate powder, an active pharmaceutical ingredient (API). Capreomycin sulfate solutions were analysed after artificial degradation (alkaline or acid hydrolysis) to demonstrate the resolution, selectivity, and efficiency of the experimental chromatographic system. The authors used an Agilent 1100 liquid chromatography instrument (Agilent Technologies) and chromatographic columns: Kinetex C18, YMC-Triart С18, ACQUITY UPLC BEH C18, ACQUITY UPLC BEH C8, ACQUITY UPLC BEH Phenyl, and ACQUITY UPLC CSH C18 (experimental procedure) or Acclaim C18, Zorbax SB-C18, and XBridge BEH130 C18 (The International Pharmacopoeia procedure).Results. In contrast to pharmacopoeial procedures, which evaluate only the component composition, the experimental procedure under the selected chromatography conditions can determine both the component composition and related substances of capreomycin. This advantage results from substituting a column packed with 1.7 µm particles for a 5 µm column required for pharmacopoeial procedures. The experimental procedure remains suitable for liquid chromatography instruments with a pressure limit of no more than 400 bar in the gradient elution mode with two mobile phases. According to the efficiency and selectivity evaluation, ACQUITY UPLC BEH C18 columns (150 × 2.1 mm, 1.7 μm) provide optimal peak resolution for capreomycin isoforms and related substances after artificial degradation of capreomycin.Conclusions. This experimental procedure based on ion-pair UHPLC may be used in the production and stability testing of capreomycin medicines to evaluate the API quality by the content of its main components and related substances.

No abstract