Poly Vinylcaprolactam Research Articles

Time and Temperature Dependence of Drug Crystallization─The Role of Molecular Mobility.

Using the time-temperature-transformation diagrams, we demonstrated a correlation between molecular mobility and crystallization in amorphous solid dispersions of nifedipine (NIF) with each polyvinylpyrrolidone vinyl acetate (PVPVA64) and polyvinyl caprolactam polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus). The behavior was compared with the NIF dispersions prepared with each polyvinylpyrrolidone (PVP) and hydroxypropyl methylcellulose acetate succinate (HPMCAS) [Lalge et al., Mol. Pharmaceutics 2023, 20(3), 1806-1817]. Each system was characterized by a unique temperature at which the crystallization onset time was the shortest. Below this temperature, a coupling was observed between the α-relaxation time determined by dielectric spectroscopy and crystallization onset time. Above this temperature, the activation barrier for crystallization had a more significant role than molecular mobility. In the solid state, PVP and PVPVA64 dispersion exhibited higher resistance to crystallization than HPMCAS and Soluplus. The role of polymers in inhibiting crystal growth in nucleated systems was discerned by monitoring crystallization following wetting of the amorphous dispersion with the dissolution medium. PVPVA64 and Soluplus dispersions exhibited higher resistance to crystal growth than PVP and HPMCAS.

Current Status and Development Trend of Research on Polymer-Based Kinetic Inhibitors for Natural Gas Hydrates.

As the understanding of natural gas hydrates as a vast potential resource deepens, their importance as a future clean energy source becomes increasingly evident. However, natural gas hydrates trend towards secondary generation during extraction and transportation, leading to safety issues such as pipeline blockages. Consequently, developing new and efficient natural gas hydrate inhibitors has become a focal point in hydrate research. Kinetic hydrate inhibitors (KHIs) offer an effective solution by disrupting the nucleation and growth processes of hydrates without altering their thermodynamic equilibrium conditions. This paper systematically reviews the latest research progress and development trends in KHIs for natural gas hydrates, covering their development history, classification, and inhibition mechanisms. It particularly focuses on the chemical properties, inhibition effects, and mechanisms of polymer inhibitors such as polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap). Studies indicate that these polymer inhibitors provide an economical and efficient solution due to their low dosage and environmental friendliness. Additionally, this paper explores the environmental impact and biodegradability of these inhibitors, offering guidance for future research, including the development, optimization, and environmental assessment of new inhibitors. Through a comprehensive analysis of existing research, this work aims to provide a theoretical foundation and technical reference for the commercial development of natural gas hydrates, promoting their safe and efficient use as a clean energy resource.

Effect of Modified Polyvinyl Caprolactam on Gold Recovery from Fine Slime in Gold Ore Flotation

Effect of Modified Polyvinyl Caprolactam on Gold Recovery from Fine Slime in Gold Ore Flotation

Insights into the synergistic effect of polylactam kinetic hydrate inhibitor and amino acid via molecular dynamics simulations

Technological innovation is urgently needed to solve the problem of hydrate formation in oil and gas transmission pipelines for the flow assurance guarantee. Typical kinetic hydrate inhibitors for industrial application are the combination of lactam-based polymers with solvent synergists. In this study, a novel non-solvent synergist leucine (Leu) was proposed for improving the kinetic inhibition effect of polyvinyl caprolactam (PVCap). The synergism of PVCap and Leu was investigated via molecular dynamics simulations. Results showed that the 1 wt% PVCap + 2 wt% Leu system can totally inhibit methane hydrate formation within the simulation period, and the combination systems with other concentrations have negligible effects on delaying hydrate nucleation but can significantly slow down the hydrate growth rate. The excellent synergism of PVCap and Leu may be due to the large diffusion coefficient of the molecules in the systems, which provides a high probability for the aggregation of methane molecules and induces the formation of bubbles. In addition, the bubbles can be further stabilized by the amphiphilic PVCap and Leu molecules around it. This study also provides new insights to develop powerful synergists for PVCap, which would be helpful to the design strategy of KHIs with high efficiency.

Fabrication of PLGA Nanoparticles Using Combination of PCL-PVA-PEG Copolymer as Surfactant: In-Vitro Characterization and Cytotoxicity Study

Objective: The present study aimed to fabricate Poly lactic acid co-glycolic acid (PLGA) nanoparticles loaded with resveratrol using a novel graft co-polymer surfactant named Soluplus®. Methods: The PLGA nanoparticles were prepared in the present study using polyvinyl caprolactam polyvinyl acetate polyethylene glycol amphiphilic graft copolymer named Soluplus® as surfactant through double emulsification and single emulsification-solvent evaporation method. The formulations were prepared successfully to encapsulate the drug resveratrol, and then evaluated for their particle size, polydispersity index, zeta potential, drug loading and the degree of entrapment of the drug. A scanning electron microscope was used to examine the morphology of the nanoparticles. In vitro drug release was assessed and, mathematical pharmacokinetic modelling was done to assess the release pattern. A comparative cytotoxicity study between free drug and prepared nanoparticles using MTT assay was carried out for cell viability evaluation. Uptake and internalization of nanoparticles were also studied using confocal fluorescence microscopy. Results: The results demonstrated successful fabrication of the PLGA nanoparticles using the Soluplus as polymer surfactant. The drug, polymer and the all the excipients were found to be compatible and did not indicate any interaction. The results also indicated the prepared nanoparticles (SF2) as suitable resveratrol delivery vehicle in terms of the compliant particle size (344.6 ±6.63 nm), polydispersity index (0.962), zeta potential (- 18.5±1.21), drug loading (18.94± 0.27%), the entrapment efficiency (39.62±0.17%) and drug release (75.13±0.17%). The shape and surface morphology of the formulated nanoparticles were found to be spherical and smooth. Cytotoxicity study also demonstrated significant reduction of cell viability by the nanoparticle compared to free resveratrol. The highest cytotoxicity of SF2 against MCF7 cell was found in 2000 nM concentration with 3.03±0.05 percent of cell viability. It was found that the percentage of growth inhibition was increasing with increasing concentration of SF2 and IC50 value of this assay was 108.94 μg/ml. Conclusion: It has been found that the Resveratrol loaded PLGA nanoparticles were successfully formulated and found to perform better in terms of efficacy and cytotoxicity.

Impacts of Triethylene Glycol and Polyvinyl Caprolactam on Dissociation Conditions and Complete Inhibition Region of Methane Hydrate

Impacts of Triethylene Glycol and Polyvinyl Caprolactam on Dissociation Conditions and Complete Inhibition Region of Methane Hydrate

Investigation of the interaction of modified polyvinyl caprolactam with the surface of minerals included in the composition of polycomponent ores

Investigation of the interaction of modified polyvinyl caprolactam with the surface of minerals included in the composition of polycomponent ores

Effect of a Terminated PVCap on Methane Gas Hydrate Formation

Polyvinylcaprolactam (PVCap) is an economic kinetic inhibitor for hydrate formation in pipelines during oil and gas transportation. However, its application is limited because of the low inhibition performance under certain conditions. In this work, a modified PVCap on its chain end is proposed. 2-amino-3-propionic acid mercapto-terminated polyvinyl caprolactam (PVCap-NH2-COOH) was synthesized and its performance as a KHI for methane hydrate formation was evaluated under different conditions. Results showed that the performance of PVCap-NH2-COOH as a KHI was better than that of PVCap at the same concentrations. Gas hydrate samples with 1 wt.% PVCap-NH2-COOH were measured using Raman spectroscopy, XRD, and cryo-SEM. PVCap-NH2-COOH had a selective action on a specific crystal surface of the hydrates and could prevent methane molecules from entering large cages. Its inhibition ability increased with the decrease in the occupancy rate of large cages. The morphology of the gas hydrate crystal changed from porous in a pure water system to a chaotic but compact structure state in the system with PVCap-NH2-COOH.

Влияние желатина трески и альгината натрия на нуклеацию газовых гидратов

This work studied the effect of mixtures of fish gelatin (protein) from Atlantic cod skin and sodium alginate (polysaccharide) from brown algae on the nucleation of sII methane-propane hydrate. The rocking cell method with ramp cooling was employed to determine the supercooling required for the hydrates formation from solutions of individual polymers and their mixtures.Unlike sodium alginate, which has practically no effect on the formation of gas hydrates, the gelatin inhibitory activity was intermediate between polyvinylpyrrolidone and polyvinyl caprolactam (commercial kinetic hydrate inhibitors). In the caseof polymer blends, a slight decrease in the efficacy of gelatin at fixed content was observed as the sodium alginate concentration decreased. The results indicate the antagonism of the kinetic inhibition of methane-propane hydrate by mixtures of biological polyelectrolytes. Undoubtedly, intermolecular interactions in polysaccharide-gelatin complexes in solution affect the abilityof polymers to retard the nucleation process. A more detailed study of the kinetics of hydrate formation depending on the ratio of polymers in solution will make it possible to reveal the mechanism of their influence and to propose mixed reagentsto control the hydrate formation.

Development of Highly Efficient Dual-Purpose Gas Hydrate and Corrosion Inhibitors for Flow Assurance Application: An Experimental and Computational Study

Gas hydrate and corrosion inhibitors are widely used to ensure successful and economic hydrocarbon stream flow inside the oil and gas pipelines. However, compatibility problems are observed during their co-injection into the flowlines as they have different molecular chemistry. Modifying effective gas hydrate inhibitors, such as polyvinylcaprolactam (PVCap), with some active functional groups in corrosion inhibition, can overcome compatibility issues. In this study, maleic anhydride was used as a cheap monomer to synthesize ionic N-vinyl caprolactam/maleic-based copolymers (P(VCap-co-MA)) as potential dual-purpose gas hydrate and corrosion inhibitors. The gas hydrate experiments showed that the inhibitors effectively inhibited natural gas hydrate formation and a maximum subcooling temperature of 14.6 °C achieved in a solution containing 2500 ppm P(VCap-co-MA)-3. The molecular dynamics simulation revealed that P(VCap-co-MA)-3 reduced the gas concentration in the liquid phase and occupied its adsorption sites on the hydrate surface to form a steric hindrance effect, inhibiting the gas hydrate formation. Electrochemical measurements indicated that P(VCap-co-MA)s significantly suppressed steel corrosion in oilfield-produced water saturated with H2S and CO2. P(VCap-co-MA)-3 and P(VCap-co-MA)-5 provided the highest protection of 96.9 and 96.1% in H2S and CO2 media, respectively. Moreover, simulation studies demonstrated that the inhibitors are strongly adsorbed on the steel surface to form a barrier layer on the surface, protecting against corrosive electrolytes. These findings suggest that the modification of a gas hydrate inhibitor improves not only its corrosion and gas hydrate inhibition performance but also decreases the operation costs for flow assurance in the oil and gas pipelines.

INVESTIGATION OF ANTI-PILLING PROPERTIES OF DIFFERENT FABRICS APPLIED WITH POLYVINYLCAPROLACTAM

Pilling is one of the most important problems in the textile industry still not confidently solved. The problem is a kind of mechanically caused fabric defect consisting by a series of roughly spherical masses of entangled fibers called pills. Many studies have been carried out to define this problem in detail, determine the pilling intensity by different methods and improve the pilling grades of fabrics. One of the most beneficial methods to improve values is chemical finishing by applying specific polymers. In this study, a specific synthesized anti-pilling polymer was used for chemical finishing by padding method. A specific polymer based on polyvinylcaprolactam (PVCL) was synthesized and applied on the fabrics. The polymer has been characterized with FT-IR, NMR, DSC, elemental analysis devices also to optimize application-parameters. Especially pilling grades of blended fabrics of natural and synthetic staple fibres are often worser then other non blended fabrics, PVCL polymer was applied on a selection of different polyester cotton blends or polyester viscose blend, which have pilling values between 2-3. PVCL-Polymer applications were carried out by using these 7 different fabrics. As a result, approximately 1.5-2 pilling degree improvement was achieved. Anti-pilling polymers applied on the fabrics used to improve pilling values often decrease hydrophilicity values of the fabrics and worsen touch. However, the specific PVCL-polymer does not lead to a loss of smooth hand neighter to a loss of smooth fabric touch. On the contrary, it improves both hydrophilicity and smooth touch not causing fabric yellowing. PCVL is distinguished from other products used for pilling improvement in the textile industry.

Dipeptides as environmentally friendly CH4 hydrate inhibitors: Experimental and computational approaches

In this study, three dipeptides (Gly-Gly, Ala-Ala, and Ala-Gly) were appraised as environmentally benign hydrate inhibitors for CH4 hydrate using both experimental and computational methods. Their kinetic inhibition performance was experimentally evaluated using a stirred high-pressure autoclave and a non-stirred high-pressure micro-differential scanning calorimeter. The experimental results demonstrated that the three dipeptides functioned well as CH4 hydrate inhibitors. Ala-Gly was found to be the most effective, and its inhibition performance was comparable to that of polyvinylcaprolactam (PVCap), a polymer-based commercial hydrate inhibitor. Snapshots, hydrate counts, F3 and F4 order parameters, displacement magnitude, mean square displacement, and radial distribution functions of each peptide-containing system were examined using molecular dynamics (MD) simulations to reveal the inhibition mechanism of dipeptides. The MD simulations showed that the N-termini of the dipeptides were the key constituents for inhibiting the CH4 hydrate, and the Ala-Gly-containing system had the strongest interaction between dipeptide molecules and CH4 hydrate. The overall results provide a better understanding of nature-derived, environmentally friendly hydrate inhibitors and offer insights into the molecular inhibition mechanism of various potential inhibitors.

Copolymer Micelle-administered Melatonin Ameliorates Hyperosmolarity-induced Ocular Surface Damage through Regulating PINK1-mediated Mitophagy

PurposeTo investigate the role and mechanism of melatonin-loaded polymer polyvinyl caprolactam–polyvinyl acetate–polyethyleneglycol graft copolymer micelles (Mel-Mic) in dry eye disease (DED).MethodsIn vitro, the apoptosis and reactive oxygen species (ROS) generation in human corneal epithelial cells (HCECs) were analyzed by immunostaining and flow cytometry. The effect of Mel-Mic on autophagy and mitophagy was evaluated by immunostaining and western blots. PINK1 knockdown was analyzed by small interfering RNA. In vivo, sodium fluorescein staining, tear secretion test, and periodic acid-Schiff staining were used to determine whether Mel-Mic can alleviate the severity of DED. Small molecule antagonists were pretreated to investigate whether melatonin type 1 and/or 2 receptors (MT1/MT2) mediate the effects of Mel-Mic.ResultsMel-Mic improved the solubility and biological activities of Mel in aqueous solutions. Treatment with Mel-Mic decreased the apoptosis of HCECs exposed to hyperosmotic medium, accompanied by downregulation of cleaved Caspase-3 and upregulation of Bcl-2. In addition, Mel-Mic application suppressed ROS overproduction, rescued mitochondrial function, and decreased the level of oxidative stress associated biomarkers (COX-2 and 4-HNE) in HCECs. Interestingly, HCECs treated with Mel-Mic exhibited increased levels of mitophagy markers (PINK1, PARKIN, Beclin 1, and LC3B) and restored impaired mitophagic flux under hyperosmolarity. While PINK1 knockdown largely abolished its protective effects. In vivo, compared to vehicle group, topical Mel-Mic-solution-treated mice showed significantly improved clinical parameters, increased tear production, and decreased goblet cells loss in a dose-dependent manner. Also, transmission electron microscopic assay revealed increased autophagosome number in the corneal epithelium of Mel-Mic group. Moreover, luzindole, a nonselective MT1/MT2 antagonist, but not 4-P-PDOT, a selective MT2 antagonist, blocked the protective effect of Mel-Mic.ConclusionsOur findings demonstrated that Mel-Mic ameliorates hyperosmolarity-induced ocular surface damage via PINK1-mediated mitophagy and may represent an effective treatment for DED possibly through acting MT1 receptor.

Tableted hydrophilic electrospun nanofibers to promote meloxicam dissolution rate

This study investigated the ability of hydrophilic electrospun nanofibers to enhance the dissolution rate of poorly soluble drug Meloxicam (MLX). The drug was loaded into polyvinylpyrrolidone (PVP), polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol (Soluplus®), sodium lauryl sulfate (SLS) nanofibers using electrospinning as fibers fabrication technique. The drug-loaded nanofibers were characterized for their diameter, inter-fibers porosity and drug dissolution profiles, carried out in four different aqueous buffers. Nanofibers loaded with MLX were grinded and used to prepare a solid unit dosage form (Tablets: 7 mm × 4 mm) to facilitate their administration. Fibers nanostructure was characterized through SEM analysis showing a mean diameter in a nanometer size range. Moreover, SEM confirmed the maintenance of fibrous structure within tablets cross section.Dissolutions rate of MLX-loaded nanofibers is improved, compared to free drug, suggesting that nanofibers could be used as suitable carrier to enhance MLX dissolution rate. Moreover, the tablet formulation proposed showed faster release rate in comparison with commercial oral forms (Mobic®) particularly in the dissolution media characterized by lower pHs.

Plasmon-Coupled Directional Emission from Soluplus-Mediated AgAu Nanoparticles for Attomolar Sensing Using a Smartphone

Although there are numerous techniques for the synthesis of plasmonic (metallic Ag and Au) nanomaterials, eco-friendly and biocompatible methodologies that present diverse applications in nanophotonics and biomedical domains are seldom reported. Soluplus is a graft copolymer of polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol and is extensively used for improving the solubility and bioavailability of poorly water-soluble drugs. However, the utility of their amphiphilic chemical structure, strong UV-light absorbing, and bifunctional properties of the polymer matrix as well as its role as a solubilizer have not been explored for rapid synthesis of plasmonic bimetallic nanohybrids. Although a variety of nanoparticles (NPs) have been studied for surface plasmon-coupled emission (SPCE) spectroscopic applications, AgAu nanohybrids have not been examined in the subject platform hitherto. In this article, we demonstrate a synthesis route for obtaining AgNPs, AuNPs, and AgAu nanohybrids using soluplus as both the reducing and capping agent in a simple UV-light induced one-pot rapid technique. These hybrid nanomaterials were interfaced with propagating surface plasmon polaritons from a 50 nm Ag thin film to understand the plasmonic coupling phenomenon in spacer, cavity, and extended cavity nanoconfigurations. The obtained AgAu nanohybrids aided in addressing the three major long-standing challenges in SPCE technology development, namely, (i) unavoidable quenching in the presence of AuNPs, (ii) chemical instability in AgNPs, and (iii) intrinsic ohmic losses in plasmonic NPs. In addition to overcoming the above-mentioned caveats, unaccustomed >1200-fold sharply directional and polarized SPCE enhancements were achieved using AgAu nanohybrids. The multifold nanogaps generated in AgAu nanohybrid sustained multiple hotspots catering to attomolar sensitivity of the SPCE reporter molecule, rhodamine B (RhB). The proposed methodology to obtain dequenched as well as augmented SPCE enhancements is of utmost utility in biophysicochemical sensor development.

Hydrophilic nanofibers as a supersaturating delivery system for carvedilol

Polymer nanofibers represent a promising delivery system for poorly water-soluble drugs; however, their supersaturating potential has not been explored yet. Here, carvedilol-loaded nanofibers based on poly(ethyleneoxide) and on amphiphilic block copolymer poloxamer 407 were produced by electrospinning. These nanofibers provided high carvedilol loading and improved dissolution of carvedilol. Their dissolution resulted in a supersaturated system that was not stable, and thus to avoid carvedilol precipitation, hydroxypropyl methylcelluloses or polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus) were additionally incorporated into the nanofibers. The morphology of the electrospun product was not affected by incorporation of carvedilol and the polymer precipitation inhibitors, as shown by scanning electron microscopy. The hydroxypropyl methylcelluloses were not effective polymer precipitation inhibitors for carvedilol. Incorporation of Soluplus significantly extended the duration of carvedilol supersaturation (>24 h) compared to the dissolution of nanofibers without Soluplus. Moreover, after 1 h of dissolution, incorporation of Soluplus into the nanofibers provided significantly higher carvedilol concentration (94.4 ± 2.5 μg/mL) compared to the nanofibers without Soluplus (32.7 ± 5.8 μg/mL), the polymer film (24.0 ± 2.2 μg/mL), and the physical mixture (3.3 ± 0.4 μg/mL). Thus, this study shows the great potential for hydrophilic nanofibers as a delivery system for sustained carvedilol supersaturation.

Design and characterisation of an amorphous formulation of nifedipine for the treatment of autonomic dysreflexia.

Current treatment for autonomic dysreflexia (AD) involves rupturing a liquid-filled soft capsule of nifedipine to aid rapid drug release and absorption, however, this application is not covered under the manufacturer's license. The objective of the current work was to design a rapidly dissolving solid dosage formulation for the treatment of AD as an alternative to the off-license "bite and swallow" use of currently available commercial products. Amorphous solid dispersions (ASDs) of nifedipine were prepared by spray-drying using three different polymers: hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrolidone (PVP) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol (Soluplus), at a 15% w/w drug loading and were formulated and compressed into tablets. Dissolution testing was performed in the paddle dissolution apparatus using either a monophasic or biphasic medium. The PVP-nifedipine ASD tablets exhibited rapid dissolution, with 35% of the total nifedipine dose dissolving within 15 min in the monophasic dissolution medium. The HPMC-nifedipine ASD exhibited a very slow dissolution, while the Solupus-nifedipine system exhibited no nifedipine release over 120 min. When tested in the biphasic dissolution medium, the PVP-nifedipine ASD tablets exhibited a release profile comparable to that of the pre-split/ruptured nifedipine soft capsule product. This study demonstrates that a nifedipine-PVP ASD is a promising formulation strategy in the treatment of AD.

Improved anticancer activity of betulinic acid on breast cancer through a grafted copolymer-based micelles system

Betulinic acid (3β-Hydroxy-20(29)-lupaene-28-oic acid, BA) has excellent anti-cancer activity but poor solubility and low bioavailability. To improve the antitumor activity of BA, a polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol (PVCL–PVA–PEG) graft copolymer (Soluplus) encapsulated BA micelle (Soluplus-BA) was fabricated. The Soluplus-BA micelles presented a mean size of 54.77 ± 1.26 nm and a polydispersity index (PDI) of 0.083. The MTT assay results showed that Soluplus-BA micelles increased the inhibitory effect of BA on MDA-MB-231 cells, mainly due to the enhanced accumulation of reactive oxygen species (ROS) and the destruction of mitochondrial membrane potential (MMP). Soluplus-BA micelles induced the DNA double-strand breaks (DSBs) as the γH2AX foci increased. Moreover, Soluplus-BA also inhibited the tube formation and migration of human umbilical vein endothelial cells (HUVECs), and inhibited the neovascularization of the chicken chorioallantoic membrane (CAM). This angiogenesis inhibitory effect may be accomplished by regulating the HIF-1/VEGF-FAK signaling pathway. The in vivo study confirmed the improved anti-tumor effect of Soluplus-BA and its inhibitory effect on angiogenesis, demonstrating the possibility of Soluplus-BA as an effective anti-breast cancer drug delivery system.

Preparation of silver-decorated Soluplus® nanoparticles and antibacterial activity towards S. epidermidis biofilms as characterized by STEM-CL spectroscopy

Biofilm infections present a serious problem because antibacterial drugs are not effective against mature biofilms or biofilms formed by drug-resistant bacteria. To address this issue, we developed a drug delivery system based on metal-decorated polymeric particles. Polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol graft copolymer (Soluplus®) is an amphiphilic polymer used in biomedical formulations, while silver nanoparticles are widely acknowledged to have high antibacterial activity. We prepared silver-decorated Soluplus® micelle nanoparticles with high antibacterial activity using the emulsion solvent diffusion method. Decoration of Soluplus® micelles with silver nanoparticles was found to increase their antibacterial activity. Scanning transmission electron microscopy-cathodoluminescence (STEM-CL) spectroscopy allows imaging of the spatial distribution of labeled targets and the chemical identification of materials. However, STEM-CL spectroscopy of fragile polymer materials is challenging. We optimized the STEM-CL spectroscopy technique to determine the distribution of silver nanoparticles in Soluplus® micelles. Additionally, the surface plasmon properties of the silver nanoparticles were successfully characterized without deactivation. The developed silver-decorated Soluplus® nanoparticles were effective against biofilm infections and have the potential to be applied for other biofilm-related diseases. Additionally, the optimized STEM-CL spectroscopy technique is expected to contribute to the analysis and imaging of fragile polymer materials, as well as other soft materials such as cells and tissues.

Design, fabrication, and characterization of graft co-polymer assisted ocular insert: a state of art in reducing post-operative pain

Purpose Targeted delivery of drugs at appropriate concentrations to ocular tissues is required to avoid wastage. Hence, advanced systems that maximize the release of poorly soluble drugs and deliver them at ocular sites must be designed. Methods In this study, Soluplus® (polyvinyl caprolactam–polyvinyl acetate–polyethylene glycol–graft copolymer) was selected as a solubilizer as well as film former for preparing ocular inserts and polyethylene glycol 400 (PEG-400) as a plasticizer. On the basis of an initial phase solubility study, the maximum concentration of Soluplus® possible was used for developing the inserts. An optimized formulation was obtained using a 32-factorial design. Two factors at three levels were used to design the ocular inserts. Soluplus® (X 1) and the plasticizer, PEG-400 (X 2), were set as the independent variables at various levels, and the Rel4h (drug release in 4 h, Y 1) and tensile strength (Y 2) were set as the dependent variables. A pre-formulation study was conducted to select suitable materials. Results Various physico-chemical parameters of the optimized formulation, including the tensile strength and folding endurance, were studied using FT-IR, DSC, XRD, and SEM. An in vitro dissolution study was conducted to determine the amount of drug released. There was no redness, swelling, or watering of the rabbit eye. Conclusion It was concluded that the ocular inserts of the poorly soluble nepafenac developed using a graft-co-polymer enhanced the solubility and utilization of the drug for a prolonged period.