Development of a MIP-Based QCM Sensor for Selective Detection of Penicillins in Aqueous Media

Pharmaceuticals wastes have been recognized as emerging pollutants to the environment. Among those, antibiotics in the aquatic environment are one of the major sources of concern, as chronic, low-dose exposure can lead to antibiotic resistance. Herein, we report on molecularly imprinted polymers (MIP) to recognize penicillin V potassium salt (PenV-K), penicillin G potassium salt (PenG-K), and amoxicillin sodium salt (Amo-Na), which belong to the most widespread group of antibiotics worldwide. Characterization and optimization led to two MIPs comprising methacrylic acid as the monomer and roughly 55% ethylene glycol dimethacrylate as the crosslinker. The obtained layers led to sensitive, selective, repeatable, and reusable sensor responses on quartz crystal microbalances (QCM). The LoD for PenV-K, PenG-K, and Amo-Na sensors are 0.25 mM, 0.30 mM, and 0.28 mM, respectively; imprinting factors reach at least around three. Furthermore, the sensors displayed relative selectivity factors of up to 50% among the three penicillins, which is appreciable given their structural similarity.

Antioxidant Activity of Amino Acid Sodium and Potassium Salts in Vegetable Oils at Frying Temperatures

Previous studies reported that several amino acids had strong antioxidant activity in vegetable oils under frying conditions. In this study, the carboxylic acid group of amino acids was converted to a carboxylate group (-COO-Na+ or -COO-K+), a heating study was conducted with amino acid salts in soybean oil at 180 ºC. Sodium salts of amino acids including alanine, phenylalanine, and proline and disodium glutamate had significantly stronger antioxidant activity than the corresponding amino acids, and potassium salts had stronger antioxidant activity than sodium salts. Potassium salts of alanine and phenylalanine more effectively retained tocopherols in soybean oil than the corresponding amino acids during heating. Phenylalanine potassium salt had stronger antioxidant activity than phenylalanine in other vegetable oils including olive, high oleic soybean, canola, avocado, and corn oils. Phenylalanine potassium salt at 5.5. mM more effectively prevented oil oxidation than tert-butyl hydroquinone (TBHQ), a synthetic antioxidant, at its legal concentration limit (0.02%) indicating its feasibility as a new antioxidant for frying.

DEVELOPMENT OF PERORAL HYPOLIPIDEMIC FORMULATION BASED ON SULFATED ARABINOGALACTAN IN THE FORM OF POTASSIUM SALT

An original heparinoid, sulfated arabinogalactan in the form of potassium salt, possessing anticoagulant and hypolipidemic activities, has been developed at the A.E. Favorsky Irkutsk Institute of Chemistry Siberian Branch of the Russian Academy of Sciences.The aim was to develop solid peroral dose forms (capsules and film-coated tablets) for the prevention and treatment of atherosclerotic lesion of blood vessels on the basis of potassium salt of sulfated arabinogalactan which would be suitable for further clinical trials of these forms.Materials and methods. The following materials were used in the work: sulfated arabinogalactan in the form of potassium salt, obtained at the A.E. Favorsky Irkutsk Institute of Chemistry Siberian Branch of the Russian Academy of Sciences; Ludipress®; AEROSIL® 200 Pharma; calcium stearate; Aquacoat ECD. The powder mixtures were briquetted followed by tableting and application of the finished film coating Aquacoat ECD, and encapsulation in hard gelatin capsules.Results. Composition and technological characteristics of capsules and film-coated tablets were determined using physico-chemical and technological properties of sulfated arabinogalactan in the form of potassium salt. Technological parameters and quality indicators were determined for the solid pharmaceutical dose forms in accordance with the requirements of the State Pharmacopoeia of the Russian Federation of the XIVth edition. Conclusion. The optimum compositions and technology for the preparation of capsules and film-coated tablets based on potassium salt of sulfated arabinogalactan for the prevention and treatment of atherosclerotic lesion of blood vessels, were developed. The data obtained were used for the regulatory documentation design.

A new guaninate hydrate K+·C5H4N5O−·H2O: crystal structure from 100 to 300 K in a comparison with 2Na+·C5H3N5O2−·7H2O

A new guanine salt hydrate, K+·C5H4N5O−·H2O, was obtained and characterized by single-crystal X-ray diffraction in the temperature range 100 K–300 K and compared with that of the previously documented sodium salt hydrate (2Na+·C5H3N5O2−·7H2O) [Gur & Shimon (2015). Acta Cryst. E71, 281–283; Gaydamaka et al. (2019). CrystEngComm, 21, 4484–4492]. Both sodium and potassium salt hydrates have channels. However, the structure of the channels, the cation coordination, the protonation (and, respectively, the charge) of the guanine anions, as well as the role of water molecules in the crystal structure are different for the two salt hydrates. In the crystal structures of the potassium salt, the guanine anions are linked via hydrogen bonds into quartets that form open cylindrical channels in a honeycomb framework. Water molecules `line the walls' of the channels, whereas the potassium cations fill the intra-channel space. This contrasts with the structure of the sodium salt hydrate in which guanine anions form channels with water molecules filling in the channel space together with sodium cations coordinating them. The 1D anionic assembly generated through numerous hydrogen bonds and cation interactions with guanine anions and water molecules is energetically the most distinctive part of the structure of the potassium salt hydrate. In the case of the guanine sodium salt, the structure contains purely inorganic polymeric fragments – sodium cations coordinated to a water molecule forming a 1D polymeric structure and guanine anions interconnecting these polymers via hydrogen bonds with water molecules. The structural differences account for the difference in the anisotropy of strain on temperature variation for the two salt hydrates: whereas in both structures the values of the bulk thermal expansion coefficients are similar in the two structures and the major expansion is observed along the channel axes, the degree of anisotropy for the K salt is more than four times higher than that for the Na salt.

Complete Assignment of the 1H and 13C NMR Spectra of Carthamin Potassium Salt Isolated from Carthamus tinctorius L.

Carthamin potassium salt isolated from Carthamus tinctorius L. was purified by an improved traditional Japanese method, without using column chromatography. The 1H and 13C nuclear magnetic resonance (NMR) signals of the pure product were fully assigned using one- and two-dimensional NMR spectroscopy, while the high purity of the potassium salt and deprotonation at the 3′ position of carthamin were confirmed by atomic adsorption spectroscopy and nano-electrospray ionization mass spectrometry.

Complete Assignment of the 1H and 13C NMR Spectra of Carthamin Potassium Salt Isolated from Carthamus Tinctorius L.

Carthamin potassium salt isolated from Carthamus tinctorius L. was purified by an improved traditional Japanese method, without using column chromatography. The 1H and 13C nuclear magnetic resonance (NMR) signals of the pure product were fully assigned using one- and two-dimensional NMR spectroscopy, while the high purity of the potassium salt and deprotonation at the 3’ position of carthamin were confirmed by atomic adsorption spectroscopy and nano-electrospray ionization mass spectrometry.