Macrogel and nanogel networks based on crosslinked poly (vinyl alcohol) for adsorption of methylene blue from aqua system

Investigation of flurbiprofen pharmacokinetics in rats following dermal administration of optimized cyclodextrin-based nanogel

PURPOSE

The main purpose of this study was to optimize a cyclodextrin-based nanogel of flurbiprofen (FP) for prolonged dermal administration and evaluate its stability, in vitro release, ex vivo skin permeation, and in vivo pharmacokinetic profile.

METHODS

The nanogels were prepared via emulsification/solvent evaporation process and optimized through design of experiments. Optimal formulation was characterized via particle size (PS), polydispersity index (PDI), zeta potential (ZP), differential scanning calorimetry (DSC) and X-ray powder diffraction (XRPD), solubility, stability, in vitro release/ex vivo permeation studies and mathematical modeling, and pharmacokinetic studies conducted in rats. Results were compared to HPMC-based gel that was not nano-sized (i.e.FP-HPMC gel).

RESULTS

The PS, PDI and ZP values of optimal FP-loaded nanogel were 295.5 nm, 0.361 and -31.9 mV, respectively and it was stable for 12 months. In in vitro release studies, the flux from the optimal FP-loaded nanogel (96.3 µg/hcm2) was three times slower (i.e.more controlled) than that of the FP-HPMC gel (287 µg/hcm2); the permeability coefficient of the nanogel (0.015 cm/h) was slightly less than that of FP-HPMC gel (0.046 cm/h). Rat skin studies showed FP-loaded nanogel provided higher drug retention in the skin, compared to FP-HPMC gel. Mathematical modeling from rat skin permeation showed the Hixson-Crowell model was the best fitting model for FP-loaded nanogel, suggesting surface area of the nanogel is changing during the release process. In rat pharmacokinetic studies, the FB-loaded nanogel exhibited prolonged and flatter plasma profile than the FP-HPMC gel, consistent with the higher drug retention in the skin.

CONCLUSION

The optimized nanogel provided prolonged drug permeation and more sustained pharmacokinetic performance compared to FP-HPMC gel.

Multifunctional Polymeric Nanogels for Biomedical Applications

Currently, research in nanoparticles as a drug delivery system has broadened to include their use as a delivery system for bioactive substances and a diagnostic or theranostic system. Nanogels, nanoparticles containing a high amount of water, have gained attention due to their advantages of colloidal stability, core-shell structure, and adjustable structural components. These advantages provide the potential to design and fabricate multifunctional nanosystems for various biomedical applications. Modified or functionalized polymers and some metals are components that markedly enhance the features of the nanogels, such as tunable amphiphilicity, biocompatibility, stimuli-responsiveness, or sensing moieties, leading to specificity, stability, and tracking abilities. Here, we review the diverse designs of core-shell structure nanogels along with studies on the fabrication and demonstration of the responsiveness of nanogels to different stimuli, temperature, pH, reductive environment, or radiation. Furthermore, additional biomedical applications are presented to illustrate the versatility of the nanogels.

Chemically modified rice husk as an effective adsorbent for removal of palladium ions

Bio-matrix of rice husk and Mobil Composition of Matter No. 41 (MCM-41) was modified with alizarin red S for preconcentration of Pd²⁺ prior flame atomic absorption spectrometric determination. The prepared bio-matrix (RH@MCM-41@ARS) was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope, energy dispersive X-ray spectrometer (SEM/EDX) and surface area studies. The impact of different parameters (solution pH, amount of sorbent, contact time, sample volume, initial Pd²⁺ concentration and diverse ions) on the uptake of Pd²⁺ were evaluated. The maximum adsorption capacity of Pd²⁺ onto RH@MCM-41@ARS was 198.2 mg g^-1 at optimum conditions. Applying the optimized procedure as a preconcentration step led to limit of detection of 0.13 μg L^-1 and dynamic analytical range up to 500 μg L^-1. The sorbent was regenerated by 0.5 mol L^-1 thiourea for at least 10 cycles without significant reduction of adsorption capacity. The method was applied for preconcentration of Pd²⁺ from real samples.

Green microwave synthesis of functionalized chitosan with robust adsorption capacities for Cr(VI) and/or RHB in complex aqueous solutions

Dinitrosalicylic acid-functionalized chitosan, CHN-DNSA, was developed and improved the adsorption property against chromium Cr(VI) and/or Rhodamine B (RHB). Here, the disposal of wastewater bearing Cr(VI) and RHB from a complex system was ascribed to significant differences in physicochemical properties. The constructed CHN-DNSA surface charge is responsible for different interactions enabling simultaneous capture of pollutants. The excellent adsorption potency of Cr(VI) at pH 3.0 was 98.4% within a remarkable 1 h and the adsorption performance was 91.1% for RHB. The ionic strength was affected, reducing the removal % of Cr(VI) to 36.7% whereas 0.1 M NaCl meliorated the removal efficiency from 91.6 to 96.2% for RHB and from 82.3 to 89.1% for a binary system. Also, the exploited elimination process of Cr(VI) and/or RHB obeyed the 2nd model of kinetics and the Freundlich system. Good recovery, superior capacity, and synthetic approach make this protocol promising for wastewater treatment.

Highly ordered functionalized mesoporous silicate nanoparticles reinforced poly (lactic acid) gatekeeper surface for infection treatment

The controlled release of a drug considers the key feature of the delivery carrier that enhances therapeutic efficacy. This study was aimed at design, synthesis of nano valve and capping systems onto caged functionalized mesoporous silica nanoparticles (SBA15) with nanoflowers polylactic acid (PLA-NF). Levofloxacin (LVX) as a specific model drug was encapsulated onto series; SBA15, SBA15@NH2, and SBA15@NH2/PLA. The examined nanocarriers released in a controlled fashion by external stimuli. The delivery vehicle based on PLA-NF coated SBA15@NH2, potent conjugated with LVX with experienced a high extent of trapping content with fast releasing by pH regulating mechanism. In vial LVX released profile and in vitro antifungal forceful of the selected microbes were detected. However, SBA15@NH2/PLA exhibited pore size, surface area and pore volume 5.4 nm, 163 and 0.011 respectively, but the significantly clear zone was obtained with Staphylococcus aureus ATCC 6538 (G+ve), Escherichia coli ATCC 25922 (G-ve), Candida albicans ATCC 10231 (yeast) and Aspergillus niger NRRL A-326 (fungus). Viability test avouch that rising functionality enhanced cytocompatibility and non-toxicity profile. Based on the aforementioned promising data, this type of nanocarriers offers when functionalized with targeting cells, the accessibility to deliver antibiotics onto nanosystem for increased potency against microbes and reduce side effects.

An adsorbent based on humic acid and carboxymethyl cellulose for efficient dye removal from aqueous solution

Adsorbents from sustainable precursors are highly desirable for practical applications. In this study, carboxymethyl cellulose (CMC) and humic acid (HA) were adopted to fabricate a composite immobilized on precipitates of calcium hydroxide (PCH) and ferric hydroxide (PFH). The as-obtained adsorbent, denoted as HA-CMC/PMH (PCH and PFH were referred to as PMH), was analyzed by infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and thermo gravimetric analysis. When applying for a typical organic pollutant of methylene blue (MB) removal from aqueous solution, a high adsorption capacity of 666.67 mg/g was achieved over HA-CMC/PMH. The adsorption mechanisms of MB involved ion exchanging and π-π interactions, this adsorption process mainly occurred on both anionic and aromatic groups. Adsorption behavior analysis indicated that Langmuir isotherm model and pseudo-second order kinetic model fitted experimental data well, suggesting a mono-layer adsorption of MB onto the adsorbent. Further thermodynamic analysis proved that the adsorption of MB onto HA-CMC/PMH was an exothermal spontaneous process. The developed adsorbent is also reusable with 79.93% of adsorption capacity remaining in the fifth recycle runs. Therefore, the adsorbent of HA-CMC/PMH is suggested to be a promising candidate for adsorption applications.