Antibacterial Porous Systems Based on Polylactide Loaded with Amikacin.

Three porous matrices based on poly(lactic acid) are proposed herein for the controlled release of amikacin. The materials were fabricated by the method of spraying a surface liquid. Description is given as to the possibility of employing a modifier, such as a silica nanocarrier, for prolonging the release of amikacin, in addition to using chitosan to improve the properties of the materials, e.g., stability and sorption capacity. Depending on their actual composition, the materials exhibited varied efficacy for drug loading, as follows: 25.4 ± 2.2 µg/mg (matrices with 0.05% w/v of chitosan), 93 ± 13 µg/mg (with 0.08% w/v SiO2 amikacin modified nanoparticles), and 96 ± 34 µg/mg (matrices without functional additives). An in vitro study confirmed extended release of the drug (amikacin, over 60 days), carried out in accordance with the mathematical Kosmyer-Pepas model for all the materials tested. The matrices were also evaluated for their effectiveness in inhibiting the growth of bacteria such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. Concurrent research was conducted on the transdermal absorption, morphology, elemental composition, and thermogravimetric properties of the released drug.

Design of dialdehyde cellulose crosslinked poly(vinyl alcohol) hydrogels for transdermal drug delivery and wound dressings.

2,3-Dialdehyde cellulose (DAC) was used as an efficient and low-toxicity crosslinker to prepare thin PVA/DAC hydrogel films designed for topical applications such as drug-loaded patches, wound dressings or cosmetic products. An optimization of hydrogel properties was achieved by the variation of two factors - the amount of crosslinker and the weight-average molecular weight (Mw) of the source PVA. The role of each factor to network parameters, mechanical, rheological and surface properties, hydrogel porosity and transdermal absorption is discussed. The best results were obtained for hydrogel films prepared using 0.25 wt% of DAC and PVA with Mw = 130 kDa, which had a high porosity and drug-loading capacity (high water content), mechanical properties allowing easy handling, best adherence to the skin from all tested samples and improved transdermal drug-delivery. Hydrogel films are biocompatible, show no cytotoxicity and have no negative impact on cell growth and morphology in their presence. Furthermore, hydrogels do not support cell migration and attachment to their surface, which should ensure easy removal of hydrogel patches even from wounded or damaged skin after use.

Formulation, Characterization and Properties of Hemp Seed Oil and Its Emulsions.

The formulation, characterization, and anticipated antibacterial properties of hemp seed oil and its emulsions were investigated. The oil obtained from the seeds of Cannabis sativa L. in refined and unrefined form was characterized using iodine, saponification, acid values, and gas chromatography, and was employed for the preparation of stable oil-in-water emulsions. The emulsions were prepared using pairs of non-ionic surfactants (Tween, Span). The effects of the emulsification method (spontaneous emulsification vs. high-intensity stirring), hydrophilic lipophilic balance (HLB), type and concentration of surfactant, and oil type on the size and distribution of the emulsion particles were investigated. It was found that the ability to form stable emulsions with small, initial particle sizes is primarily dependent on the given method of preparation and the HLB value. The most efficient method of emulsification that afforded the best emulsions with the smallest particles (151 ± 1 nm) comprised the high-energy method, and emulsions stable over the long-term were observed at HBL 9 with 10 wt % concentration of surfactants. Under high-intensity emulsification, refined and unrefined oils performed similarly. The oils as well as their emulsions were tested against the growth of selected bacteria using the disk diffusion and broth microdilution methods. The antibacterial effect of hemp seed oil was documented against Micrococcus luteus and Staphylococcus aureus subsp. aureus. The formulated emulsions did not exhibit the antibacterial activity that had been anticipated.

Characteristics of silver nanoparticles in vehicles for biological applications.

Silver nanoparticles (AgNPs) have been used for decades as anti-bacterial agents in various industrial fields such as cosmetics, health industry, food storage, textile coatings and environmental applications, although their toxicity is not fully recognized yet. Antimicrobial and catalytic activity of AgNPs depends on their size as well as structure, shape, size distribution, and physico-chemical environment. The unique properties of AgNPs require novel or modified toxicological methods for evaluation of their toxic potential combined with robust analytical methods for characterization of nanoparticles applied in relevant vehicles, e.g., culture medium with/without serum and phosphate buffered saline.