An exopolysaccharide-producing Antarctic yeast strain was selected and identified as Cryptococcus laurentii AL₁₀₀. The physiological properties of the strain and its ability to utilize and biotransform different carbon sources (pentoses, hexoses, and oligosaccharides) into exopolysaccharide and biomass were investigated. Sucrose was chosen as a suitable and accessible carbon source. The biosynthetic capacity of the strain was studied in its dynamics at different sucrose concentrations (20, 30, 40, and 50 g/L) and temperatures (22 and 24 °C). The maximum biopolymer quantity of 6.4 g/L was obtained at 40 g/L of sucrose, 22 °C temperature and 96-h fermentation duration. The newly synthesized microbial carbohydrate was a heteropolysaccharide having the following monosaccharide composition: arabinose, 61.1%; mannose, 15.0%; glucose, 12.0%; galactose, 5.9%; and rhamnose, 2.8%. It was characterized by polydispersity of the polymer molecule, 60% of it having molecular mass of 4200 Da. The exopolysaccharide demonstrated good emulsifying and stabilizing properties with regard to oil/water emulsions and a pronounced synergistic effect with other hydrocolloids such as xanthan gum, guar gum, and alginate.

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The purpose of the study was to investigate the stability and biopharmaceutical characteristics of ketoprofen, loaded in polymeric carriers, which were included into a bigel in a semisolid dosage form. The polymer carriers with in situ-included ketoprofen were obtained by emulsifier-free emulsion polymerization of the monomers in aqueous medium or a solution of the polymers used. The morphological characteristics of the carriers, the in vitro release and the photochemical stability of ketoprofen were evaluated. The model with optimal characteristics was included in a bigel formulation. The bigel was characterized in terms of pH, rheological behavior, spreadability, and in vitro drug release. Acute skin toxicity, antinociceptive activity, anti-inflammatory activity, and antihyperalgesic effects of the prepared bigel with ketoprofen-loaded polymer carrier were evaluated. The carriers of ketoprofen were characterized by a high yield and drug loading. The particle size distribution varied widely according to the polymer used, and a sustained release was provided for up to 6 hours. The polymer mixture poly(vinyl acetate) and hydroxypropyl cellulose as a drug carrier, alone or included in the bigel composition, improved the photostability of the drug compared with unprotected ketoprofen. The bigel with ketoprofen-loaded particles provided sustained release of the drug and had optimal rheological parameters. In vivo experiments on the bigel showed no skin inflammation or irritation. Four hours after its application, a well-defined analgesic, anti-inflammatory, and antihyperalgesic effect was registered. The polymer mixture of poly(vinyl acetate) and hydroxypropyl cellulose as a carrier of ketoprofen and the bigel in which it was included provided an enhanced photostability and sustained drug release.

The Sporobolomyces salmonicolor AL(1) Antarctic strain was cultivated and two bioproducts were obtained: exopolysaccharide and biomass. The biologically active substances ergosterol, torularhodin, torulene, β-carotene and CoQ(10) were extracted from the biomass and were quantified as follows: ergosterol 5.2 ± 0.2 mg/g, torularhodin 458.3 ± 24.5 μg/g, torulene 273.7 ± 14.5 μg/g, β-carotene 129.2 ± 7.3 μg/g and coenzyme Q(10) (CoQ(10)) 236.1 ± 12.1 μg/g. Their antioxidant activity was estimated according to the cathode voltammetry method. The most pronounced antioxidant activity (according to trolox) was exhibited by β-carotene 3.78, followed by CoQ(10) 3.60, both of them being the main contributors to the total extract activity of 3.19. The biologically active metabolites in combination with exoglucomannan as emulsifier were used for the creation of model emulsion systems characterised by great stability. The absorption of UVA rays by the model emulsions was studied.

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Until now, the interest to plants from genus Scutellaria in Bulgaria has been focused mainly on the terpenes in them. The purpose of this study is to enrich the information on the composition of the Bulgarian Scutellaria species in terms of both polyphenolic content as well as primary metabolites such as mono-, oligosaccharides and organic acids. An aerial part of three Scutellaria species growing in four low mountain regions of Southern Bulgaria was used. The flavonoids scutellarin, baicalin, baicalein, wogonin, wogonoside, luteolin, chrysin and a caffeoyl phenylethanoid glycoside-verbascoside have been identified via HPLC in different extracts from Scutellaria altissima, Scutellaria albida and Scutellaria galericulata. The antioxidant activity of the extracts has been evaluated. The Scutellaria altissima from Mezek and Scutellaria galericulata from Parvenets we studied, which are the richest in flavonoids (represented mainly by baicalin, scutellarin and wogonoside), show the highest Oxygen Radical Absorption Capacity. Hydroxyl Radical Averting Capacity of Scutellaria albida from Mezek and Scutellaria altissima from Bachkovo is the most pronounced, probably due to the content of scutellarin and luteolin and chrysin, respectively. Antioxidant activity of aqueous, methanolic and 70% and 96% ethanol extracts were also determined by the electrochemical method.

The effect of different doses of visible (Vis), ultraviolet-capital A, Cyrillic (UVA), and mixed light (UVA + Vis) upon coenzyme Q(10) (CoQ(10)) and beta-carotene synthesis and biomass yield by the Sporobolomyces salmonicolor AL(1), Cryptococcus albidus AS(55), Cryptococcus laurentii AS(56), and C. laurentii AS(58) strains isolated from Antarctic samples was investigated. The beta-carotene concentration in the red strain biomass increased by 52% under irradiation with 11 J/cm(2) Vis, and the CoQ(10) concentration rose by 37% in relation to the control quantity obtained through dark cultivation. Under irradiation with 6 J/cm(2) UVA, the S. salmonicolor AL(1) strain synthesized 15% more beta-carotene; C. albidus AS(55), 22%; C. laurentii AS(56), 44%; and C. laurentii AS(58), 35% in relation to the control quantity. Irradiation with a low UVcapital A, Cyrillic + Vis dose significantly stimulated beta-carotene biosynthesis by the strains of the Cryptococcus genus (87%, 138%, and 100%), whereas S. salmonicolor AL(1) increased the beta-carotene content to a smaller degree (55%). Higher doses of all three irradiation types inhibited beta-carotene accumulation. Vis suppressed CoQ(10) biosynthesis in the Cryptococcus strains, whereas UVcapital A, Cyrillic and UVcapital A, Cyrillic + Vis inhibited it in all four strains. The S. salmonicolor AL(1) strain pre-treated with 0.02 J/cm(2) UVA synthesized twice as much CoQ(10) and beta-carotene when cultivated in the presence of Vis light in an 11-J/cm(2) dose.

The aim of the study was to investigate the influence of the nature and composition of the monomer feed, added to the reaction system indomethacin/vinyl acetate/3-dimethyl (methacryloyloxyethyl) aminopropyl sulfonate (IMC/VAc/DMAPS) and the characteristics of the obtained polymer latexes on indomethacin In-situ loading, its kinetic release properties, and drug stability. Indomethacin loaded nanoparticles were obtained by an emulsifier-free emulsion radical copolymerization of the monomers, in presence of the drug. Transmission electron microscopy, Attenuated Total Reflection Fourier Transform Infrared spectroscopic analyses, Particle size distribution and zeta potential analysis were carried out to characterize the In-situ loaded nanocarriers. High-performance liquid chromatography and UV/VIS spectroscopic analyses were applied to determine the drug loading, In vitro release properties and stability studies of the drug used. High yield of 90 to 96% was obtained for the tested In-situ loaded nanocarriers. They possess a spherical shape with diameter ranging from 100 to 900 nm and zeta potential from -3.25 mV to -20.3 mV. Mono-modal and bi-modal particle size distribution was observed depending on monomer feed, added to the reaction system. It also influenced the drug loading and its release characteristics. Indomethacin was released from the investigated patterns following first order release. The nature and composition of the monomer feed, added to the reaction system IMC/VAc/DMAPS are an effective factors for the control of the indomethacin loading and also affect the rate and extent of drug-releasing but do not influence the kinetic model and drug transport mechanism. Stability studies indicated the stabilizing role of the polymer carrier on the In-situ included indomethacin.