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In this study, polymer-based microparticles are used to improve the therapeutic properties of ceftriaxone (CEF) and render them safer. Poly-3-hydroxybutyrate (P3HB) and poly-3-hydroxybutyrate/polye...

The production of poly-3-hydroxybutyrate (P3HB) and poly-3-hydroxybutyrate/polyethylene glycol (PEG)-based microparticles, loaded with antitumor drugs paclitaxel (PTX) and 5-Fluorouracil (5-FU) by spray-drying technique, was investigated. The average diameter of microparticles was found to be 3.4 ± 0.5 µm and zeta potential was about −44 mV. The addition of surfactant PEG did not show any effect on the morphological characteristics of the particles. But the chemical structure of drug influenced on the properties. Microparticles had heterogeneous pores on the surface when the hydrophobic PTX was encapsulated. It was established that the addition of surfactant positively influenced on the properties of particles and led to the loading of 5-FU directly into the matrix. This is confirmed by the results of electron microscopy and dynamics of drug release in vitro. As a whole, the release profiles of PTX and 5-FU from composite P3HB/PEG microparticles were less than from P3HB microparticles. The results...

The present study reports the herbicidal activity of metribuzin and tribenuron-methyl embedded in the degradable matrix of natural poly-3-hydroxybutyrate [P(3HB)/MET and P(3HB)/TBM]. The developed formulations were constructed as films and microgranules, which were tested against the weeds such as white sweet clover Melilotus albus and lamb's quarters Chenopodium album in the presence of soft spring wheat (Triticum aestivum, cv. Altaiskaya 70) as the subject crop for investigation. The activity was measured in laboratory scale experiments by determining the density and weight of the vegetative organs of weeds. The study was also aimed at testing the effect of the experimental formulation on the growth of wheat crop as dependent on the method of herbicide delivery. The experimental MET and TBM formulations showed pronounced herbicidal activity against the weed species used in the study. The effectiveness of the experimental formulations in inhibiting weed growth was comparable to and, sometimes, higher than that of the commercial formulations (positive control). The amount of the biomass of the wheat treated with the experimental herbicide formulations was significantly greater than that of the wheat treated with commercial formulations.

Matrices based on resorbable polyhydroxyalkanoates (PHAs) of five types {a homopolymer of 3-hydroxybutyric acid, copolymers of 3-hydroxybutyric and 4-hydroxybutyric acids [P(3HB/4HB)], 3-hydroxybutyric and 3-hydroxyvaleric acids [P(3HB/3HV)], 3-hydroxybutyric and 3-hydroxyhexanoic acids [P(3HB/3HHx)]} have been constructed and characterised. No significant differences have been found in tissue response to implantation of these PHAs. Non-coarse fibrous capsules that formed around PHA matrices reached their maximum thickness (60–90 μm) 90 days after implantation; by day 180, the average thickness of the capsules had decreased by 1·5–2·3 times. The number of foreign body giant cells, resorbing PHAs, remained high. In vivo biodegradation behaviour of polymer matrices is related to the chemical composition of the PHA. Matrices prepared from copolymers P(3HB/4HB) and P(3HB/3HHx) exhibited the fastest degradation rates. P3HB/3HV matrices were degraded more slowly, and P3HB matrices were the most durable....

Samples of olyhydroxyalkanoates (PHAs), polyhydroxybutyrate (PHB) and copolymers poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 4 and 18 mol% hydroxyvalerate, synthesized by the bacteria Ralstonia eutropha B5786, were investigated. PHA films in contact with blood did not activate the hemostasis system at the level of cell response, but they did activate the coagulation system and the complement reaction. To detect biologically-active components in the PHAs, a detailed analysis of the composition of the polymers was conducted. Gas chromatography-mass spectrometry revealed long-chain fatty acids (FAs) in the tested PHAs. Their total concentration in the polymer ranged from tenths of mol% to 2-3 mol%, depending on the purification method. C16:0 constituted the largest proportion, up to 70%. Of the long-chain hydroxy acids, only beta-OH-C14:0 was detected and it did not exceed 0.06 mol%. The analysis of the hemocompatibility properties of the PHAs purified by a specialized procedure, including the quantitative and morphological estimation of platelets adherent to the surface of polymer films, the plasma recalcification time and complement activation studies, indicated that PHB and PHBV can be used in contact with blood. It has been found out that the lipopolysaccharides of bacteria producing PHAs, which contain mostly long-chain hydroxy acids, can be the factor activating the hemostasis systems. Thus, the technology of PHA purification must satisfy rather stringent specific requirements.