Polymer Pluronic F127 Research Articles

Development of Transdermal Formulation Integrating Polymer-Based Solid Microneedles and Thermoresponsive Gel Fucoidan for Antiaging: Proof of Concept Study.

Skin can be damaged by intense and prolonged exposure to ultraviolet (UV) radiation. Photoaging and acute damage from sun exposure result in collagen degradation and enzymatic activity decline in the skin. Fucoidan (FUC) exhibits potential antiaging properties, including collagen synthesis promotion and enzyme activity inhibition. However, FUC's limited ability to penetrate the skin layers due to its large molecular weight makes it a challenge for topical application. In this study, we successfully developed a new approach by integrating thermoresponsive gel (TRG) containing FUC with solid microneedles (SMNs) as a delivery system. TRG is formulated using a combination of Pluronic F127 (PF127) and Pluronic F68 (PF68) polymers, while SMNs are made from a mixture of poly(vinyl alcohol) (PVA) and poly(vinylpyrrolidone) (PVP) polymers with a variety of cross-linkers. Based on the results of ex vivo testing, it was shown that more than 80% of FUC can be delivered using the optimized formula. Furthermore, the results of the in vitro blood hemolytic test showed that TRG-FUC-SMNs were relatively biocompatible. In vivo antiaging activity tests using a rat model exposed to UV for 14 days showed that histological assessment, skin elasticity measurement, wrinkle evaluation, and skin moisture content had no significant differences (p < 0.05) compared to the positive control group. In contrast, a significant difference (p < 0.05) was observed when comparing the TRG-FUC-SMNs group with the group that received only TRG-FUC without pretreatment and negative controls. These findings suggest that FUC has potential to be delivered using the TRG system in combination with SMNs to harness its antiaging properties.

Effect of diphenylalanine on the functional activity of porphyrin and non-porphyrin photosensitizers solubilized by Pluronic F127

The effect of the diphenylalanine (Phe-Phe) amino acid on the rate of tryptophan photooxidation catalyzed by photosensitizers (PS) of different natures: dimegin (DMG), fluorinated tetraphenylporphyrin (FTPP), photoditazine (PD) and methylene blue (MB) was studied. It was shown that in the presence of Phe-Phe, the effective constant of photooxidation of the substrate catalyzed by DMG, PD and MB in the aqueous phase decreases. However, the introduction of the amphiphilic polymer Pluronic F127 into the systems allows not only to restore, but also to increase the activity of the PS in the processes of photosensitized oxidation. In particular, the activity of dimegin solubilized by Pluronic F127 in the presence of Phe-Phe is higher than the activity of both pure porphyrin and solubilized DMG. In addition, the activity of the hydrophobic FTPP solubilized by Pluronic also increases. At the same time, a study of the luminescence of singlet oxygen generated by solubilized FTPP in the absence and presence of Phe-Phe revealed that the dipeptide does not influence the processes of 1О2 generation. It was suggested that micellar catalysis influences the activity of solubilized PS in the presence of a biologically active dipeptide.

Chitosan oligosaccharide/pluronic F127 micelles exhibiting anti-biofilm effect to treat bacterial keratitis

Mono or dual chitosan oligosaccharide lactate (COL)-conjugated pluronic F127 polymers, FCOL1 and FCOL2 were prepared, self-assembled to form micelles, and loaded with gatifloxacin. The Gati@FCOL1/Gati@FCOL2 micelles preparation process was optimized by QbD analysis. Micelles were characterized thoroughly for size, CMC, drug compatibility, and viscosity by GPC, DLS, SEM, IR, DSC, and XRD. The micelles exhibited good cellular uptake in both monolayers and spheroids of HCEC. The antibacterial and anti-biofilm activities of the micelles were evaluated on P. aeruginosa and S. aureus. The anti-quorum sensing activity was explored in P. aeruginosa by analyzing micelles' ability to produce virulence factors, including AHLs, pyocyanin, and the motility behavior of the organism. Gati@FCOL2 Ms was mucoadhesive, cornea-penetrant, antibacterial, and inhibited the biofilm formation by P. aeruginosa and S. aureus significantly more than Gati@FCOL1. A significant reduction in bacterial load in mice cornea was observed after Gati@FCOL2 Ms-treatment to the P. aeruginosa-induced bacterial keratitis-infected mice.

Ex Vivo and In Vivo Retention Time Evaluation of Fucoidan Isolated from Macrocystis pyrifera Through a Thermosensitive Gel System in The Vaginal Route

This study evaluated Fucoidan from Macrocystis pyrifera as a potential treatment for cervical cancer. The research aimed to examine Fucoidan’s in vivo retention capacities in poloxamer-based in situ gels for vaginal drug delivery systems. Five different thermosensitive gel formulations were developed, each with varying concentrations of Pluronic F127 and F68 polymers. The incorporation of HPMC affected the gelation temperature, viscosity, and bioadhesive strength. The accepted formula, F3, had a bioadhesive value of 5415.93 ± 98.74 dyne/cm2 and could form a gel at physiological temperature. Ex vivo animal models showed that Fucoidan components retained well on vaginal tissue. Only F1, F2, and F3 achieved the media after 8 hours of examination. In vivo evaluation showed F3 had the highest drug concentration retained in the vaginal mucosa of female rats after 8 hours (24,115 ± 4,842 g), slowly removed after 24 hours (13,014 ± 5,596 g). In conclusion, increases in the hydrophilic content of formulations led to the retained hydrogel formula, which increased drug release and lowered intravaginal elimination.

Enhanced apoptotic activity of Pluronic F127 polymer-encapsulated chlorogenic acid nanoparticles through the PI3K/Akt/mTOR signaling pathway in liver cancer cells and in vivo toxicity studies in zebrafish

Abstract In this study, chlorogenic acid nanoparticles encapsulated in Pluronic F127 polymer were synthesized and characterized to determine if they could treat human liver cancer. The nanoparticles were synthesized using standard procedures and characterized using physical and biological techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, UV-Vis, dynamic light scattering, Photoluminescence, scanning electron microscopy, and transmission electron microscopy. The anticancer effects were assessed using MTT analysis, acridine orange/ethidium bromide, reactive oxygen species (ROS), COMET assay, annexin-V/FITC, cell cycle analysis, and expression of marker genes against HepG2 cell lines. The results showed significant cytotoxicity, apoptosis induction, and increased ROS production in treated cells compared to control cells. The nanoparticles also activated the apoptotic cascade and regulated the PI3K/AKT/mTOR pathways. The nanocomposites exhibited unique characteristics such as anticancer efficacy in vitro. Further research was conducted using zebrafish to model hematological parameters, liver enzymes, and histopathology to study effectiveness. Green-synthesized Pluronic F127–chlorogenic acid nanoparticles can be considered potential cancer therapy agents.

Synthesis, structure and properties of nanoparticles based on SrFe12-xRxO19 (R = Er, Tm) compounds

In this work a comprehensive analysis of the structure and properties of doped SrFe12-xRxO19 (R = Er, Tm) hexaferrites has been studied. The hexaferrtes were synthesized by two methods: mechanochemical and citrate approaches. The solubility of rare-earth elements (REE) has been studied by precision determination of the lattice spacings and cell volume of the samples, synthesized by mechanochemical method. It has been shown that the solubility of Er and Tm at a temperature of 1200 °C does not exceed × = 0.08 REE ions per formula unit. According to Mössbauer spectroscopy, REE atoms preferentially occupy 12k positions. Nanoparticles of SrFe12-xRxO19 (R = Er,Tm) compounds for MRI were obtained by high-energy ball milling of the citrate samples for 50 h in an octadecene solution with oleic acid. Stable hydrosols of nanoparticles were obtained after their coating with Pluronic F127 polymer. It has been shown that the obtained nanoparticles can be used for biomedical applications as contrast agents.

Synthesis of thermoresponsive composite hydrogel from Pluronic F127 reinforced by oil palm empty fruit bunches-extracted cellulose for silver sulfadiazine drug delivery

Hydrogels are modern dermal drug-delivery media which can hold a huge amount of water and modify their structure to enable spontaneous response to temperature change and are thus attractive to overcome the limitations of conventional drug-delivery media. In this study, a sustainable method was developed to synthesize thermoresponsive Pluronic F127 (PF127) composite hydrogel reinforced by cellulose extracted from oil palm empty fruit bunches (OPEFBs). The thermoresponsive cellulose/PF127 composite hydrogels were formulated by dissolving OPEFB-extracted cellulose in aqueous sodium hydroxide/urea solution prior to mixing with PF127 polymer at low temperature. The performance of the synthesized thermoresponsive cellulose/PF127 composite hydrogels was evaluated in terms of their swelling ratio, percentage of degradation, and in vitro silver sulfadiazine (AgSD) drug release. PCT20 thermoresponsive cellulose/PF127 composite hydrogel with 20 w/v% PF127 and 3 w/v% OPEFB cellulose showed high mechanical strength (storage modulus and complex viscosity values of 20.90 kPa and 2.09 kPa s, respectively), relatively high swelling ratio (3.63 ± 0.43), and prolonged release of AgSD (t50% value of 4 h) compared with PCT17-PCT19 thermoresponsive cellulose/PF127 composite hydrogels. Besides, AgSD-loaded thermo-responsive cellulose/PF127 composite hydrogels showed relatively good inhibitory activity against the Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Enterococcus faecium, Streptococcus pyogenes, and Klebsiella pneumoniae bacteria. The exploration of thermoresponsive cellulose/PF127 composite hydrogel from OPEFBs can promote sustainable, environment-friendly, and cost-effective drug delivery systems by using abundant agricultural biomass.

Protein‐Coated Biodegradable Gas‐Stabilizing Nanoparticles for Cancer Therapy and Diagnosis Using Focused Ultrasound

AbstractSurface‐engineered hydrophobic nanoparticles that can stabilize small gas pockets on their surfaces (i.e., gas‐stabilizing nanoparticles, GSNs) have been recently shown to be excellent contrast and cavitation agents for ultrasound theranostics. However, previously developed GSNs are not biodegradable, which limits their clinical translation potential. Here the development of biodegradable GSNs is shown by coating hydrophobically modified mesoporous silica nanoparticles with different protein solutions. It is found that these novel GSNs retain strong cavitation activity while rapidly degrading in simulated body fluid (SBF) or in vivo in days or a few weeks, respectively. Interestingly, GSNs coated with other stabilizing layers, Pluronic F127 polymer or phospholipids, demonstrated significantly slower degradation rates with only partial degradation even after a month of incubation in SBF. Next, it is shown that these biodegradable GSNs can be used to ablate tumor xenografts at lower ultrasound intensities, thus avoiding the side effects of high‐intensity ultrasound. Finally, it is shown that only tumors treated with GSNs and ultrasound can specifically enrich for circulating tumor DNA, which will improve liquid biopsies for understanding tumor heterogeneity and treatment response. Overall, this study details a simple yet effective method for preparing biodegradable GSNs with broad potential for applications in cancer diagnosis and therapy.

Fabrication of pH responsive hydrogel blends of chondroitin sulfate/pluronic F-127 for the controlled release of ketorolac: its characterization and acute oral toxicity study

Objective Ketorolac tromethamine (KT), selected as a model drug, is used in management of moderate to severe acute pain. It has a short half-life (∼5.5 h) and requires frequent dose administration when needed for longer period of time. In our current project, we designed pH responsive hydrogel blends of chondroitin sulfate/pluronic F-127 (CS/Pl) for the controlled release of ketorolac. Methods Hydrogel blends were fabricated using free radical polymerization reaction technique utilizing different ratios of chondroitin sulfate (CS) (polymer) and pluronic F-127 (polymer), acrylic acid (monomer), N,N′-methyl-bisacrylamide (MBA) (cross-linker), initiator ammonium persulfate (APS) and tween-80 (surfactant). The fabricated hydrogel blends were studied and evaluated for pH responsiveness, swelling, water absorbency, in vitro drug release, and morphological characteristics such as SEM, XRD, FTIR, and TGA/DSC. Acute toxicity study was performed on rabbits. Results Maximum swelling and water absorbency were shown by CS/Pl blends being significantly greater at 7.4 (basic pH) than in 1.2 (acidic pH). In vitro dissolution demonstrated pH responsive controlled KT release following zero order at higher pH (7.4) medium up to 36 h. FTIR studies confirmed the structures of our blends; SEM results showed porous framework; thermal studies revealed higher stability of hydrogels than the individual polymers; and XRD confirmed the nature of our blends. Toxicity study revealed the nontoxic nature of the hydrogel blends. Conclusion The prepared CS/Pl hydrogels demonstrated stimuli-controlled release with delivery of drug for prolonged period of time and thus can minimize dosing frequency, safe drug delivery, increased patient compliance and easiness.

Confocal imaging of biomarkers at a single-cell resolution: quantifying 'living' in 3D-printable engineered living material based on Pluronic F-127 and yeast Saccharomyces cerevisiae

BackgroundEngineered living materials (ELMs) combine living cells with non-living scaffolds to obtain life-like characteristics, such as biosensing, growth, and self-repair. Some ELMs can be 3D-printed and are called bioinks, and their scaffolds are mostly hydrogel-based. One such scaffold is polymer Pluronic F127, a liquid at 4 °C but a biocompatible hydrogel at room temperature. In such thermally-reversible hydrogel, the microorganism-hydrogel interactions remain uncharacterized, making truly durable 3D-bioprinted ELMs elusive.MethodsWe demonstrate the methodology to assess cell-scaffold interactions by characterizing intact alive yeast cells in cross-linked F127-based hydrogels, using genetically encoded ratiometric biosensors to measure intracellular ATP and cytosolic pH at a single-cell level through confocal imaging.ResultsWhen embedded in hydrogel, cells were ATP-rich, in exponential or stationary phase, and assembled into microcolonies, which sometimes merged into larger superstructures. The hydrogels supported (micro)aerobic conditions and induced a nutrient gradient that limited microcolony size. External compounds could diffuse at least 2.7 mm into the hydrogels, although for optimal yeast growth bioprinted structures should be thinner than 0.6 mm. Moreover, the hydrogels could carry whole-cell copper biosensors, shielding them from contaminations and providing them with nutrients.ConclusionsF127-based hydrogels are promising scaffolds for 3D-bioprinted ELMs, supporting a heterogeneous cell population primarily shaped by nutrient availability.Graphical

Enhancing the active site accessibility of cobalt-silica catalysts for improved Fenton-like performance

The narrow pore channels of cobalt-silica (CoSi) catalyst generated by conventional sol–gel process limited the active site accessibility. In this work, mesoporous CoSi catalysts containing highly dispersed Co sites were synthesized by a facile sol–gel derived soft-templating technique and tested for the Fenton-like oxidation of dyes and antibiotics. By controlling the concentration of triblock polymer Pluronic F127 template, the textural and chemical properties of CoSi catalysts were fine-tuned to improve the accessibility of their active sites. The CoSi catalyst achieved ∼ 96% removal of acid orange 7 (AO7) within 15 min using a low catalyst loading (50 mg L−1) and H2O2 dosage (11 mM) at pH of 7–8. Moreover, thin-film CoSi coated on Al2O3 foam, as a monolithic catalyst prepared by the washcoating method, maintained high oxidation activity (∼99% removal for AO7) over 10 days, demonstrating excellent operational stability and process intensification for practical wastewater treatment applications.

2D Covalent Organic Framework Direct Osteogenic Differentiation of Stem Cells.

2D covalent organic frameworks (COFs) are an emerging class of crystalline porous organic polymers with a wide-range of potential applications. However, poor processability, aqueous instability, and low water dispersibility greatly limit their practical biomedical implementation. Herein, a new class of hydrolytically stable 2D COFs for sustained delivery of drugs to direct stem cell fate is reported. Specifically, a boronate-based COF (COF-5) is stabilized using amphiphilic polymer Pluronic F127 (PLU) to produce COF-PLU nanoparticles with thickness of ≈25nm and diameter ≈200nm. These nanoparticles are internalized via clathrin-mediated endocytosis and have high cytocompatibility (half-inhibitory concentration ≈1mg mL-1 ). Interestingly, the 2D COFs induce osteogenic differentiation in human mesenchymal stem cells, which is unique. In addition, an osteogenic agent-dexamethasone-is able to be loaded within the porous structure of COFs for sustained delivery which further enhances the osteoinductive ability. These results demonstrate for the first time the fabrication of hydrolytically stable 2D COFs for sustained delivery of dexamethasone and demonstrate its osteoinductive characteristics.

New indocyanine green therapeutic fluorescence nanoprobes assisted high-efficient photothermal therapy for cervical cancer

Photothermal therapy (PTT) is a promising and non-invasive treatment for cancer. As essential factors for PTT, photothermal agents (PTAs) have attracted widespread attention. However, high-efficient and biocompatible fluorescent PTAs are still not enough. In this study, new indocyanine green (IR820) was utilized as a fluorescence agent and a PTA on HeLa cells and subcutaneous cervical cancer models of mouse. To improve PTT effect and biocompatibility of IR820, the amphiphilic polymer Pluronic F-127 (F-127) was utilized to modify free IR820 molecules, to form IR820@F-127 nanoparticles (NPs) by self-assembly method. Fortunately, IR820@F-127 NPs exhibited desirable photothermal properties with high photothermal conversion efficiency of 35.2% and good photothermal stability. Cytotoxicity assay, in vitro and in vivo fluorescence imaging of IR820@F-127 NPs exhibited satisfactory biocompatibility, excellent cellular uptake ability, and bioimaging capability on tumor sites. Meanwhile, IR820@F-127 NPs owned cellular-therapy ability against cervical cancer under 793 nm laser irradiation observed in apoptosis assay. Furthermore, the excellent PTT effect (∼90%) in flow cytometry analysis endowed IR820@F-127 NPs with the ability to ablate subcutaneous cervical tumors on nude mice. The newly formed IR820@F-127 NPs have great potential for anti-tumor therapy and bioimaging of cervical cancer, which lays the foundation for the future development of biomedical applications.

Bioconjugation of Active Ingredients to Plant Viral Nanoparticles Is Enhanced by Preincubation with a Pluronic F127 Polymer Scaffold.

Proteinaceous nanoparticles can be used to deliver large payloads of active ingredients, which is advantageous in medicine and agriculture. However, the conjugation of hydrophobic ligands to hydrophilic nanocarriers such as plant viral nanoparticles (plant VNPs) can result in aggregation by reducing overall solubility. Given the benefits of hydrophilic nanocarrier platforms for targeted delivery and multivalent ligand display, coupled with the versatility of hydrophobic drugs, contrast agents, and peptides, this is an issue that must be addressed to realize their full potential. Here, we report two preincubation strategies that use a Pluronic F127 polymer scaffold to prevent the aggregation of conjugated plant VNPs: a plant VNP-polymer precoat (COAT) and an active ingredient formulation combined with a plant VNP-polymer precoat (FORMCOAT). The broad applications of these modified conjugation strategies were highlighted by testing their compatibility with three types of bioconjugation chemistry: N-hydroxysuccinimide ester-amine coupling, maleimide-thiol coupling, and copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry). The COAT and FORMCOAT strategies promoted efficient bioconjugation and prevented the aggregation that accompanies conventional bioconjugation methods, thus improving the stability, homogeneity, and translational potential of plant VNP conjugates in medicine and agriculture.

Serum Albumin Antifouling Effects of Hydroxypropyl‐Cellulose and Pluronic F127 Adsorbed on Isobutyramide‐Grafted Stellate Silica Nanoparticles

AbstractLimiting the serum protein fouling is a major challenge in the design of nanoparticles (NPs) for nanomedicine applications. Suitable chemical surface modification strategies allow to limit the interactions with adsorbing proteins. In this communication, we address the potential of isobutyramide (IBAM) groups grafted on stellate silica nanoparticles (STMS) for the immobilization of two biocompatible polymers renown for biomedical and low fouling applications: Hydroxypropylcellulose (HPC) and Pluronic F127 (PF127). We report that both polymers can be loaded on STMS@IBAM NPs surface with a maximum loading content close to 10 wt %. Regarding their antifouling properties, we report that the coatings of such HPC or PF127 polymers allow to reduce significantly the human serum albumin (HSA) adsorption in average by 70 % as compared to the surface of the free polymer STMS@IBAM. These results highlight the antifouling potential of these polymer pre‐treatments on IBAM‐modified STMS NPs surface.

A H2O2-activatable nanoprobe for diagnosing interstitial cystitis and liver ischemia-reperfusion injury via multispectral optoacoustic tomography and NIR-II fluorescent imaging

Developing high-quality NIR-II fluorophores (emission in 1000–1700 nm) for in vivo imaging is of great significance. Benzothiadiazole-core fluorophores are an important class of NIR-II dyes, yet ongoing limitations such as aggregation-caused quenching in aqueous milieu and non-activatable response are still major obstacles for their biological applications. Here, we devise an activatable nanoprobe to address these limitations. A molecular probe named BTPE-NO2 is synthesized by linking a benzothiadiazole core with two tetraphenylene groups serving as hydrophobic molecular rotors, followed by incorporating two nitrophenyloxoacetamide units at both ends of the core as recognition moieties and fluorescence quenchers. An FDA-approved amphiphilic polymer Pluronic F127 is then employed to encapsulate the molecular BTPE-NO2 to render the nanoprobe BTPE-NO2@F127. The pathological levels of H2O2 in the disease sites cleave the nitrophenyloxoacetamide groups and activate the probe, thereby generating strong fluorescent emission (950~1200 nm) and ultrasound signal for multi-mode imaging of inflammatory diseases. The nanoprobe can therefore function as a robust tool for detecting and imaging the disease sites with NIR-II fluorescent and multispectral optoacoustic tomography (MSOT) imaging. Moreover, the three-dimensional MSOT images can be obtained for visualizing and locating the disease foci.

Green Synthesis of Thermo-Responsive Hydrogel from Oil Palm Empty Fruit Bunches Cellulose for Sustained Drug Delivery.

Drug delivery is a difficult task in the field of dermal therapeutics, particularly in the treatment of burns, wounds, and skin diseases. Conventional drug delivery mediums have some limitations, including poor retention on skin/wound, inconvenience in administration, and uncontrolled drug release profile. Hydrogels able to absorb large amount of water and give a spontaneous response to stimuli imposed on them are an attractive solution to overcome the limitations of conventional drug delivery media. The objective of this study is to explore a green synthesis method for the development of thermo-responsive cellulose hydrogel using cellulose extracted from oil palm empty fruit bunches (OPEFB). A cold method was employed to prepare thermo-responsive cellulose hydrogels by incorporating OPEFB-extracted cellulose and Pluronic F127 (PF127) polymer. The performance of the synthesized thermo-responsive cellulose hydrogels were evaluated in terms of their swelling ratio, percentage of degradation, and in-vitro silver sulfadiazine (SSD) drug release. H8 thermo-responsive cellulose hydrogel with 20 w/v% PF127 and 3 w/v% OPEFB extracted cellulose content was the best formulation, given its high storage modulus and complex viscosity (81 kPa and 9.6 kPa.s, respectively), high swelling ratio (4.22 ± 0.70), and low degradation rate (31.3 ± 5.9%), in addition to high t50% value of 24 h in SSD in-vitro drug release to accomplish sustained drug release. The exploration of thermo-responsive cellulose hydrogel from OPEFB would promote cost-effective and sustainable drug delivery system with using abundantly available agricultural biomass.

Engineering photo-controllable fragrance release with flash nanoprecipitation

Controllable profragrance nanoparticles are in great demand for long-lasting scent in flavor and fragrance industries. However, the practical applications of controllable fragrance release are limited by the non-tunable size, structural heterogeneity and poor reproducibility. Herein, a coumarin-derived phototrigger (CM-OH) is covalently conjugated with alcohol fragrances to obtain the corresponding profragrances (CM-R) which enable to release fragrances under the light controlling conditions. Furthermore, we introduce a new engineering strategy to construct fine tunable and highly uniform profragrance nanoparticles with flash nanoprecipitation (FNP) technology, which features commercial available amphiphilic pluronic F127 polymers by encapsulation of photo-activatable profragrances CM-R in hydrophobic cores to enhance the long-lasting photo-controllable fragrance release. With the assistance of FNP technology, amphiphilic pluronic polymer and profragrances CM-R in organic solution are instantaneously mixed and subsequently precipitated in the multi-inlet vortex mixer (MIVM), thus obtaining the pluronic F127-encapsulated profragrance nanoparticles with good homogeneity. Compared to the traditional thermodynamic encapsulation method, the novel kinetic FNP technology can not only tune the size of profragrance nanoparticles with narrow distribution, but also distinctly improve the batch-to-batch reproducibility, which affords an alternative method for scale-up preparation of amphiphilic profragrance nanoparticles in precisely controllable fragrance delivery system.

Improved lifetime and stability of copper species in hierarchical, copper-incorporated CuSAPO-34 verified by catalytic model reactions.

The first successful synthesis of hierarchical CuSAPO-34 (3.9 wt% Cu) is reported using the polymer Pluronic F127 as a mesoporous structure directing agent (SDA). X-Ray absorption spectroscopy (XAS) revealed single site Cu2+ with 4 nearest oxygen neighbours at 1.96 Å. A catalytic model reaction, the selective reduction of NO with different sized hydrocarbons as reductants, explained that Cu2+ is accessible and reactive in both micro- and mesopores of the hierarchical CuSAPO-34. The presence of mesopores resulted in superior lifetime of the hierarchical CuSAPO-34 in the catalytic model reaction, selective oxidation of propene.

Investigation of Polymeric Micellar Nanoparticles of Amlodipine Besylatefor Transdermal Delivery

: Objectives: The objective of this study was to formulate and investigate amlodipine besylate loaded polymeric micelles and their effect on enhancing transdermal permeation of the poorly water-soluble drug via transdermal films. Methods: Pluronic F127 and Pluronic F68 polymers were chosen to prepare micelles in different drug – polymer ratios. Prepared formulations were characterised for surface morphology, micelle size, polydispersity index, zeta potential, loading efficiency, percentage drug weight in micelles and stability. Optimized amlodipine micelle dispersions were incorporated into hydroxypropyl methylcellulose K100 and polyvinyl pyrrolidone K30 transdermal films prepared by the solvent casting method. These films were evaluated for thickness, percentage weight variation, folding endurance, moisture absorbance, percentage drug content, ex vivo permeation and in vivo skin irritation. Results: Selected micelle formulations had the desired vesicle size, homogeneity and stability. Scanning electron microscopy show spherical vesicles. Micelle incorporated transdermal films were smooth, flexible, translucent and mechanically strong. The ex vivo skin permeation studies reveal that the flux of amlodipine besylate from the micelle incorporated transdermal films was significantly higher than that containing the free drug, confirming the drug solubilizing effects of micelles. Reconstitution of micelles from optimized films revealed that the original characteristics of the micelles were intact. Studies in Wistar rats showed that the prepared transdermal films were free of irritation potential when evaluated by the Draize dermal irritation scoring system. Conclusion: Beside their solubilizing effect, Pluronic micelles could be useful as novel drug carriers for enhancing transdermal permeation of Amlodipine besylate and thus its bioavailability.Key words: Hydroxypropyl methylcellulose, Micelle, Nanoparticle, Permeation, Pluronic, Skin irritation.