Biocompatible waterborne polyurethane-urea elastomer as intelligent anticancer drug release matrix: A sustained drug release study

Development of lactic acid based chain extender and soybean oil-derived polyurethanes for ecofriendly sustained drug delivery systems

In the present study, a range of sustainable, biocompatible and biodegradable polyurethanes (PU-1 to PU-4) were synthesized using different combinations of biobased polyol (obtained through the epoxidation of soybean oil, followed by ring opening with ethanol) and polyethylene glycol (PEG) and isophorone diisocyanate. The sustainable chain extender used in this study was synthesized by the esterification of lactic acid with ethylene glycol (EG). The synthesized PU samples were characterized through scanning electron microscopy (SEM), Fourier transformed infrared (FTIR) and nuclear magnetic resonance (1H NMR and 13C NMR) spectroscopy. Wetting ability and thermal degradation analysis (TGA) of the samples were also studied. Subsequently, these PUs were examined as potential drug delivery systems using Gabapentin as a model drug, which was loaded in the polymer matrix using the solvent evaporation method. The drug release studies were carried out in 0.06 N HCl as a release medium according to the method outlined in the United States Pharmacopeia. The maximum drug release was observed for sample PU-P1, which was found to be 53.0 % after 6 h. Moreover, a comparison of different PU samples revealed a trend wherein the values of drug release were decreased with an increase in the PEG content.

Application of Metal-Organic Frameworks for Efficient Removal of Doxorubicin Hydrochloride: Removal Process Optimization and Biological Activity

This study looked at the doxorubicin hydrochloride (DOX) anticancer drug's adsorption characteristics on a silver-based metal-organic framework (Ag-MOF). X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used for the characterization of Ag-MOF. The pore volume and surface area of Ag-MOF were determined through Brunauer-Emmett-Teller (BET) testing at 77 K to be 0.509 cm3/g and 676.059 m2/g, respectively. Adsorption at pH 6 was established to be the best for DOX compared to alkaline solution. Ag-MOF has a good capacity for eliminating DOX (1.85 mmol/g), according to adsorption experiments. From the adsorption results, we can find that Langmuir is the most fitted adsorption isotherm model and the pseudo-second order model best fitted the adsorption kinetics. The energy of activation for adsorption, which was determined to be 15.23 kJ/mol, also supported a chemisorption process. The mechanism of adsorption was evaluated, and details of all possible interactions between DOX and Ag-MOF were illustrated. On the other hand, while examining the impact of temperature, we identified the thermodynamic constraints as ΔG°, ΔH°, and ΔS° and confirmed that the reaction was an endothermic one and spontaneous. Even after numerous reuse cycles, the efficiency remained constant. The synthetic adsorbent was remarkably recyclable at a rate of more than 91.6%. By using the MTT assay, the cytotoxicity of the tested Ag-MOF and DOX@Ag-MOF against human breast cancer cells (MCF-7) was evaluated in vitro. The in vitro antimicrobial activity of Ag-MOF and DOX@Ag-MOF was also tested.

N-Doped Graphene Quantum Dot Nanoparticle Synthesis of Optical Active Thermal Stable Polyurea Nanocomposites Using Polybutadiene Chain Modification

Geminate thermal stability with optical characteristics is a moving forward achievement in the preparation of polybutadiene-based polyurea nanocomposites. In this regard, nitrogen-doped graphene quantum dots were synthesized from a one-pot hydrothermal reaction of citric acid with urea in an aqueous solution. An in situ polymerization approach was used for the synthesis of polyurea from the reaction of telechelic amine functionalized polybutadiene and toluene diisocyanate (TDI) in the presence of the DBTDL catalyst. Nanocomposites were prepared using 1–3 weight percent of graphene N-quantum dot nanoparticles in the polymer matrix. 1H-NMR and FT-IR spectroscopy techniques elaborated successful synthesis of primary polymer binder, polyurea and nanocomposites. Thermal degradation and characteristics were investigated using the TGA/DTG and DSC methods; lower degradation rates with progressed thermal stabilities as well as proportionate thermal characteristics with wider thermal service range were obtained especially in 3 wt% nanocomposite. Optical behavior information of samples was studied using UV-vis absorption and photoluminescence (PL) spectrometers. EDX, SEM, and AFM techniques confirmed successful nanoparticle and nanocomposite synthesis with improved morphologic and topographic properties.

Controlled preparation of grafted starch modified with Ni nanoparticles for biodegradable polymer nanocomposites and its application in food packaging

Grafting of starch with methyl methacrylate was carried out using a free radical mechanism. Free radicals were generated by the thermal disintegration of potassium persulphate at the temperature of 60°C. A variety of experimental methods were investigated to check the effect of different parameters such as (temperature, amount of starch, quantity of monomer) for efficient grafting. The optimum temperature found for good grafting was 60°C. The initial amount of starch was taken as 0.75 g. Keeping the amount of starch constant, the quantity of monomer was reduced gradually from 10 to 2 ml in portions of 5 and 3 ml. The controlled biodegradability of the grafted product was obtained by using a 3 ml monomer in 0.75 g starch. This grafted polymer showed 31.45% biodegradability in 60 days. The nanocomposite of starch grafted methyl methacrylate was prepared by incorporating 0.02 g Ni nanoparticles in the reaction flask 15 min before the completion of reaction time. The starch grafted polymer and nanocomposite of this were fully characterized by SEM, FTIR, TGA, and DSC techniques. The soil burial method was applied to estimate the biodegradability of samples. The polymer containing Ni nanoparticles was less biodegradable than without nanoparticles. Such polymers can be efficiently used as packaging material for food items.

Role of Macrodiols in the Synthesis and Thermo-Mechanical Behavior of Anti-Tack Water Borne Polyurethane Dispersions

The texture and molecular weight of polymer drastically affect the adhesion or tack strength. Waterborne polyurethane dispersions (WBPU) have been prepared using two different macrodiols of hydroxyl terminated polybutadiene (HTPB; Mn = 2912 g/mol⁻¹) and four compositions of Polypropylene glycol (PPG Mn = 425, 1000, 2000, 2700 g/mol⁻¹). The contents of the macrodiols have been varied using HTPB as 5, 10 and 15 mol%. The prepolymer of HTPB and Poly propylene glycol (PPG) have been developed using 4,4-Methylene bis(cyclohexyl isocyanate) (H₁₂MDI) which is extended using 1, 4 butanediol (BD) followed by the dispersion of polymers in deionized water. Fourier Transform Infra-red spectroscopy (FTIR) is used to confirm the desired PU linkage. The probe tack graphs for tack analysis have not shown any plateau indicating absence of fibrillation. Two different values of glass transition temperature (Tg) have been observed for each dispersion using Differential Scanning Calorimetry(DSC). Storage modulus (E′) up to 3.97 MPa and (tanδ/E′) from 0.01–0.30 MPa⁻¹ has been observed via Dynamic Mechanical Analysis (DMA). Introducing the HTPB has resulted in a decrease in the values of (tanδ/E′). No adhesion favorable parameters have been retrieved, indicating the molar variation a key factor in the development of anti-tack dispersions.

Preparation of Polydimethylsiloxane-Modified Waterborne Polyurethane Coatings for Marine Applications

A series of waterborne polyurethane dispersions (WPUs) modified with hydroxyl-terminated polydimethylsiloxane (PDMS) were prepared by incorporating PDMS into the soft segments of polyurethane chains. The structural characteristics of the prepared samples were analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and particle size analysis (PSA). The effect of PDMS content on the thermal and mechanical properties of PDMS-modified waterborne polyurethanes (PS-WPU) was investigated. In addition, the water resistance and dimensional stability of the PS-WPU were investigated by measuring its water absorption ratio and water contact angle along with universal testing machine measurements.

Effect of organic solvents on solvatochromic, fluorescence, and electrochemical properties of synthesized thiazolylcoumarin derivatives

In this present investigation, thiazolylcoumarin derivatives (5a-5k) were synthesized from thiosemicarbazide, ethyl acetoacetate, and naphthaldehyde through a multistep route. The formation of thiazolylcoumarin derivatives with bioactive scaffolds was confirmed through nuclear magnetic resonance spectroscopy. A solvatochromic study of synthesized thiazolylcoumarin derivatives was carried out using ultraviolet-visible methods for dimethylformamide (DMF), ethyl acetate, and ethanol solvents. The redox behaviour of as-synthesized thiazolylcoumarin derivatives (5a-5k) was examined in dimethyl sulphoxide by conducting an electrochemical study. Fluorescence properties of thiazolylcoumarin derivatives were studied in DMF, ethanol, and ethyl acetate to visualize the solvent effect on the emitting ability of thiazolylcoumarin derivatives.

Advances in Waterborne Polyurethane and Polyurethane-Urea Dispersions and Their Eco-friendly Derivatives: A Review

Polyurethanes and polyurethane-ureas, particularly their water-based dispersions, have gained relevance as an extremely versatile area based on environmentally friendly approaches. The evolution of their synthesis methods, and the nature of the reactants (or compounds involved in the process) towards increasingly sustainable pathways, has positioned these dispersions as a relevant and essential product for diverse application frameworks. Therefore, in this work, it is intended to show the progress in the field of polyurethane and polyurethane-urea dispersions over decades, since their initial synthesis approaches. Thus, the review covers from the basic concepts of polyurethane chemistry to the evolution of the dispersion's preparation strategies. Moreover, an analysis of the recent trends of using renewable reactants and enhanced green strategies, including the current legislation, directed to limit the toxicity and potentiate the sustainability of dispersions, is described. The review also highlights the strengths of the dispersions added with diverse renewable additives, namely, cellulose, starch or chitosan, providing some noteworthy results. Similarly, dispersion's potential to be processed by diverse methods is shown, evidencing, with different examples, their suitability in a variety of scenarios, outstanding their versatility even for high requirement applications.

Modulation of Thermally Activated Delayed Fluorescence in Waterborne Polyurethanes via Charge-Transfer Effect

Here, we designed several waterborne polyurethanes (WPUs) with efficient thermally activated delayed fluorescence (TADF) via serving charge-transfer (CT) states as a mediate bridge between singlet and triplet states to boost reverse intersystem crossing (RISC). By tuning substituents of diphenyl sulfone (DS), we found that O,O'- and S,S'-substituted DS covalently incorporated in WPUs solely show typical fluorescence emission with lifetimes in the nanosecond range. Interestingly, TADF appears by replacing the substituent with the nitrogen atom, of which lifetimes are up to ≈10 microseconds and ≈1 millisecond in air and vacuum, respectively, even though the energy gap between singlet and triplet states (ΔE_ST ) is still large for generating TADF. To explain this phenomenon, an energy level mode based on CT states and an ³ (n-π*) receiver state was proposed. By the rational modulation of CT states, it is possible to tune the ΔE_ST to render TADF-based materials suitable for versatile applications.

Waterborne poly(urethane-urea)s films as a sustained release system for ketoconazole

Ketoconazole (KTZ) was incorporated in waterborne poly(urethane-urea)s dispersions (WPUU), aiming at the production of films for drug sustained release. Dispersions based on poly(ethylene glycol-block-propylene glycol) (PEG-b-PPG) (four monomers with different contents of PEG hydrophilic segments), poly(propylene glycol), isophorone diisocyanate, dime-thylolpropionic acid and hydrazine were produced and characterized by apparent viscosity and average particle size (APS). Cast films-drug interaction was investigated by Fourier-Transform infrared spectrometry (FTIR). In vitro dissolution assays were performed in simulated gastrointestinal juices, followed by application of kinetic models. Stable pseudoplastic dispersions, with APS between 27 to 320 nm were obtained. FTIR from KTZ-loaded films indicated interactions between polymer and drug. In vitro release of KTZ was achieved above 80%, notably influenced by PEG-based segments content up to 2 h, followed by sustained release for 8 h. Higuchi’s and first-order equations described the drug kinetic profile, as diffusion of the drug and erosion of the swollen polymer, respectively.