Nonionic surfactant vesicles as a novel drug delivery system for increasing the oral bioavailability of Ginsenoside Rb1

Adsorption characteristics of antibiotics on microplastics: The effect of surface contamination with an anionic surfactant

Microplastics and antibiotics are common, typical pollutants, and they can cause compound pollution where they coexist in the environment. Surfactants in the environment can change the interface characteristics of pollutants, and then drive the change of environmental behavior of pollutants. In this paper, we studied the physicochemical properties of complexes of polystyrene (PS) and polyethylene (PE) contaminated with sodium dodecyl benzene sulfonate (SDBS); the complexes are referred to as SPS and SPE, respectively. Taking oxytetracycline (OTC) and norfloxacin (NOR) as representatives of broad-spectrum antibiotics, the effects of SDBS on the adsorption behavior of PS and PE were analyzed and possible mechanisms were proposed. The results showed that SDBS could effectively combine with PS and PE to enhance the surface electronegativity and reduce the Brunner-Emmett-Teller (BET) specific surface area and porosity. The crystal structure remained basically unchanged, and the surface functional groups changed slightly. SDBS greatly enhanced the saturated adsorption capacities of PS and PE for OTC and NOR, and made adsorption easier, which reduced the Gibbs free energy of the adsorption system. The adsorption behaviors of SPS and SPE for the two antibiotics were consistent with the Elovich kinetic model and Sips isothermal model. SDBS enhanced the hydrophilicity of the microplastics, which facilitated their adsorption of antibiotics dissolved in water. SDBS could directly combine with antibiotics to form a complex, further increasing the adsorption capacity of the microplastics for antibiotics. The -SO₃H in SDBS could combine with oxygen-containing functional groups and -NH₂ in OTC and NOR. Non-ionic covalent bonds, electrostatic interactions, and hydrophobic attraction between the alkyl chain and benzene ring also played a role in adsorption. SDBS made it possible for MPs to load more types and quantities of pollutants and change their preferential adsorption selectivity, which significantly aggravated the environmental hazards.

Nanovesicles-Mediated Drug Delivery for Oral Bioavailability Enhancement

Bioavailability is an eternal topic that cannot be circumvented by peroral drug delivery. Adequate blood drug exposure after oral administration is a prerequisite for effective treatment. Nanovesicles as pleiotropic oral vehicles can solubilize, encapsulate, stabilize an active ingredient and promote the payload absorption via various mechanisms. Vesicular systems with nanoscale size, such as liposomes, niosomes and polymersomes, provide a versatile platform for oral delivery of drugs with distinct nature. The amphiphilicity of vesicles in structure allows hydrophilic and lipophilic molecule(s) either or both to be loaded, being encapsulated in the aqueous cavity or the inner core, respectively. Depending on high oral transport efficiency based on their structural flexibility, gastrointestinal stability, biocompatibility, and/or intestinal epithelial affinity, nanovesicles can markedly augment the oral bioavailability of various poorly absorbed drugs. Vesicular drug delivery systems (VDDSs) demonstrate a lot of preferences and are becoming more prominent of late years in biomedical applications. Equally, these systems can potentiate a drug's therapeutic index by ameliorating the oral absorption. This review devotes to comment on various VDDSs with special emphasis on the peroral drug delivery. The classification of nanovesicles, preparative processes, intestinal transport mechanisms, in vivo fate, and design rationale were expounded. Knowledge on vesicles-mediated oral drug delivery for bioavailability enhancement has been properly provided. It can be concluded that VDDSs with many merits will step into an energetic arena in oral drug delivery.

Recent advances of biosurfactant for waste and pollution bioremediation: Substitutions of petroleum-based surfactants

Biosurfactant is one of the emerging compounds in the industrial sector that behaves similarly with their synthetic counterparts, as they can reduce surface and interfacial tension between two fluids. Their unique properties also enable biosurfactant molecules to be able to clump together to form micelles that can capture targeted molecules within a solution. Biosurfactants are compared with synthetic surfactants on various applications for which the results shows that biosurfactants are fully capable of replacing synthetic surfactants in applications including enhanced oil recovery and wastewater treatment applications. Biosurfactants are able to be used in different applications as well since they are less toxic than synthetic surfactants. These applications include bioremediation on oil spills in the marine environment and bioremediation for contaminated soil and water, as well as a different approach on the pharmaceutical applications. The future of biosurfactants in the pharmaceutical industry and petroleum industry as well as challenges faced for implementing biosurfactants into large-scale applications are also discussed at the end of this review.