Single Evaporation Research Articles

Liquid phase model and its coupling interaction with the ambient gas for the droplet heating and evaporation of highly volatile R134a

Droplet evaporation plays a decisive role in determining the evolutions of droplet temperature, diameter, and velocity in sprays with low saturation temperature and high volatile mediums. This study conducts a comparative analysis of liquid phase models for single droplet heating and evaporation of high volatile R134a. Three traditional liquid phase models based on the assumption of infinitely large liquid thermal conductivity (lumped), limited thermal conductivity, and effective thermal conductivity and a recently proposed third-order polynomial temperature profile (third-order) liquid phase model based on the presentation of the temperature profile inside the droplet in cubic polynomial form without solving the heat conduction equation are introduced to predict the temporal evolutions of droplet temperature, diameter, and velocity, and the spatial evolution of temperature within the droplet. The coupling of heat and mass transfer between the droplet and its surrounding gas is incorporated into the liquid phase models to investigate its effect on droplet evaporation. The droplet temperature first undergoes a rapid decrease at the transient stage of evaporation and then decreases slowly to the minimum temperature (Tmin). The droplet temperature in the transient stage depends highly on the choice of liquid phase models. Tmin is mostly unaffected by the liquid phase models. The dependence of the droplet diameter at the transient stage of evaporation on the choice of the liquid phase model is stronger compared with the following steady stage. The droplet velocity is rarely influenced in the whole evaporation. The liquid phase models incorporating the coupling weaken the evaporation intensity, resulting in a high droplet temperature and large droplet diameter. The third-order liquid phase model incorporating the coupling model predicts Tmin and agrees with the experimental data. This model can reflect reasonably the heat transfer enhancement by the recirculation inside the droplet for moving droplet.

Single droplet ignition models via evaporation and ignition competition

There is individual droplet burning phenomenon in spray flames but the ignition prediction and criteria are lack of both experimental and theoretical study. In this paper, firstly based on the energy balance analysis method, two new droplet ignition models are proposed by analyzing the single droplet evaporation and ignition process in relatively static high temperature air environment. These new models can be used to predict the droplet ignition phenomenon in spray flames. Then, single droplets of RP3 aviation kerosene, common kerosene and diesel were suspended in static air environment with ambient temperature from 845 ​K to 1085 ​K to test the ignition limits of the fuel droplet. The experimental ignition boundary was obtained by measuring and recording the minimum ignitable initial diameters of the experimental droplet in every temperature condition. The experimental results show that the ignitable minimum initial diameter of the fuel droplet decreases along with the increase of ambient temperature. And at the same ambient temperature, the minimum ignitable initial diameter of common kerosene droplet is the biggest, then is diesel and RP3 aviation kerosene is the smallest. Finally, the predicted ignition boundaries of the two new models are compared with the experimental data. And the comparison results show that the models’ predictions are in good agreement with the experimental data, whose error is within 10%.

Controllable deposition of organic metal halide perovskite films with wafer-scale uniformity by single source flash evaporation

Conventional solution-processing techniques such as the spin-coating method have been used successfully to reveal excellent properties of organic–inorganic halide perovskites (OHPs) for optoelectronic devices such as solar cell and light-emitting diode, but it is essential to explore other deposition techniques compatible with large-scale production. Single-source flash evaporation technique, in which a single source of materials of interest is rapidly heated to be deposited in a few seconds, is one of the candidate techniques for large-scale thin film deposition of OHPs. In this work, we investigated the reliability and controllability of the single-source flash evaporation technique for methylammonium lead iodide (MAPbI3) perovskite. In-depth statistical analysis was employed to demonstrate that the MAPbI3 films prepared via the flash evaporation have an ultrasmooth surface and uniform thickness throughout the 4-inch wafer scale. We also show that the thickness and grain size of the MAPbI3 film can be controlled by adjusting the amount of the source and number of deposition steps. Finally, the excellent large-area uniformity of the physical properties of the deposited thin films can be transferred to the uniformity in the device performance of MAPbI3 photodetectors prepared by flash evaporation which exhibited the responsivity of 51 mA/W and detectivity of 9.55 × 1010 Jones.

Study on the Application of MNSs/PLGA Nanocomposites in Biomedicine

The ways and effects of metal-based nanostructure (MNSs) to improve the physical or biomedical properties of PLGA polymers were studied. Firstly, the preparation methods of MNSs/PLGA nanocomposites are introduced, including solvent method, non-solvent method, MNSs direct modification method and single emulsion-solvent evaporation method. Then the applications of MNSs/PLGA nanocomposites in biomedical fields such as drug delivery, biological imaging and tissue regeneration are reviewed. Finally, the potential advantages and development trends of MNSs/PLGA nanocomposites in the treatment of diseases were analyzed on the basis of in vitro / vivo studies.

Environmental effect evaluation of refrigerator cycle with life cycle climate performance

In this study, a method to evaluate the environmental effects of household refrigerators is newly developed in terms of life cycle climate performance (LCCP). The energy consumption model of the refrigerator is developed with three types of typical single evaporator refrigerators. The operation ratio of the evaporators, which is critical for calculating the energy consumption of dual evaporator refrigerators, is determined using experimental results of serial, bypass, and parallel-circuit cycle refrigerators. The LCCP results show that the system performance and equipment manufacturing emissions are dominant factors in lifetime CO2 emissions. Therefore, energy- and material-related factors, such as refrigerator cycle options, refrigerator material, insulation, and power sources, are primarily investigated. For cycle options, CO2 emissions can be reduced by 14.7% using a two-stage cycle. For condenser materials, CO2 emissions can be reduced by 2% to 2.5% using aluminum instead of steel. For insulation, the total emissions can be reduced by up to 7.7% by applying vacuum insulation panels on each side of the refrigerator. When 20% renewable energy is supplied, the total emissions are expected to be reduced by 13% in the baseline, 19.9% in the parallel-circuit cycle, and 26% in the two-stage cycle.

Development of a loop heat pipe with kW-class heat transport capability

This paper describes the design, fabrication, and heat transfer characteristics of a loop heat pipe (LHP) with a kW-class heat transfer performance. A one-dimensional numerical model incorporating a two-phase flow pattern of the LHP condenser was developed during the design process. Based on the numerical model, a kW-class LHP comprising a single evaporator was constructed. At the evaporator, a stainless steel 316 (SUS316) box-type wick was installed, and pure water was used as the working fluid. Additionally, two types of condensers with diameters of 1/2 and 3/4 in. were manufactured based on the devised numerical model. An experimental investigation of the heat transport performance of the kW-class LHP was conducted under a cooling temperature of 30 °C using four conditions of heat dissipation at the condenser: natural air, forced air, natural water, and forced water convection. The world’s highest heat transport of 6.2 kW was achieved using the 1/2-in. diameter condenser under natural water convection. The thermal resistance between the evaporator and condenser was 0.004 °C/W, and annular flow dominated the condenser’s flow pattern. Under the other cooling conditions, maximum heat transport capabilities of 1.5, 2.5, and 4.5 kW for natural air, forced air, and forced water convection, respectively, were achieved. Conversely, due to vapor penetration from the condenser to the compensation chamber caused by stratified flow at the condenser, lower LHP performances were demonstrated by the 3/4-in. condenser under all cooling conditions. The findings confirmed that to improve heat transfer performance, the appropriate control of the two-phase flow pattern at the condenser is critical, and it is essential for the development of kW-class LHPs.

One-Pot Single-Step Route toward Bicontinuous Nanoporous Membranes of an Organic–Inorganic Core–Shell Network

Bicontinuous nanoporous materials are desirable for catalysis, storage, and separation applications. Self-assembly or phase separation of organic polymers is the general route to the structure. However, the three-dimensionally continuous organic nanostructure with a large interface area has low thermal stability and solvent resistance, limiting its applicability under various chemical environments. Here, we show a direct solution-casting preparation of a bicontinuous nanoporous membrane by utilizing the combination of phase separation, gelation, and polymerization, which occurred sequentially with the evaporation of solvent from the sol mixture of a polyurea network nanogel particle and an alkoxysilane derivative. The single evaporation process yielded a thin-film membrane with a three-dimensional reticulated nanoporous structure composed of a continuous polyurea network skeleton coated with an organosilica shell. Despite the broad pore size distribution in the 5–70 nm range, ultrafiltration through the bicontinuous conduit exhibited a sharp molecular weight cutoff near 6 nm, close to the lower limit of the pore size range. The unique filtration behavior of the bicontinuous nanoporous hybrid frameworks using the scalable and straightforward method of preparation is promising for the removal of nanoparticulate contaminants in liquids, for example, viruses in downstream processing. The porous hybrid materials of different organic–inorganic combinations may be synthesized by employing a similar approach.

Bioformulated Hesperidin-Loaded PLGA Nanoparticles Counteract the Mitochondrial-Mediated Intrinsic Apoptotic Pathway in Cancer Cells

In this study, a biological approach has carried out to develop the polymer-based nanoparticles using a bioflavonoid of hesperidin. This formulation has been attempted and established for its biomedical application in cancer treatment. Hesperidin loaded PLGA nanoparticles (Hes-PLGA-NPs) were processed by oil in water single emulsion solvent evaporation technique and the physiochemical traits were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), XRD and NMR analysis. DLS and TEM analysis revealed that the preparation yielded a spherical shaped nanoparticle with an average measure of 38.4 nm. The XRD spectrum showed a crystalline type of nanoparticles. The FTIR and NMR investigation exposed that the PLGA also serves up as capping or switching material for pH-dependent drug release. Furthermore, the cationic natures of Hes-PLGA-NPs easily penetrate cancerous cells and efficiently repressed the growth in acidic conditions. Taking into account, the findings of in vitro studies in HEp-2 cell suggested that bioformulated Hes-PLGA-NPs are more competent than native hesperidin and might be used as a potent anti-cancer candidate. Further studies are warranted to expose the toxicity and molecular level mechanisms involved in the anti-cancer activity of the synthesized Hes-PLGA-NPs as nanomedicine.

Experiments quantifying elemental and isotopic fractionations during evaporation of CAI-like melts in low-pressure hydrogen and in vacuum: Constraints on thermal processing of CAIs in the protoplanetary disk

It is widely believed that the precursors of coarse-grained CAIs in chondrites are solar nebula condensates that were later reheated and melted to a high degree. Such melting under low-pressure conditions is expected to result in evaporation of moderately volatile magnesium and silicon and their mass-dependent isotopic fractionation. The evaporation of silicate melts has been extensively studied in vacuum laboratory experiments and a large experimental database on chemical and isotopic fractionations now exists. Nevertheless, it remains unclear if vacuum evaporation of CAI-like melts adequately describes the evaporation in the hydrogen-rich gas of the solar nebula. Here we report the results of a detailed experimental study on evaporation of a such melt at 1600 °C in both vacuum and low-pressure hydrogen gas, using 1.5- and 2.5-mm diameter samples. The experiments show that although at 2 × 10−4 bar H2 magnesium and silicon evaporate ∼2.8 times faster than at 2 × 10−5 bar H2 and ∼45 times faster than in vacuum, their relative evaporation rates and isotopic fractionation factors remain the same. This means that the chemical and isotopic evolutions of all evaporation residues plot along a single evaporation trajectory regardless of experimental conditions (vacuum or low-PH2) and sample size. The independence of chemical and isotopic evaporation trajectories on PH2 of the surrounding gas imply that the existing extensive experimental database on vacuum evaporation of CAI-like materials can be safely used to model the evaporation under solar nebula conditions, taking into account the dependence of evaporation kinetics on PH2.The experimental data suggest that it would take less than 25 min at 1600 °C to evaporate 15–50% of magnesium and 5–20% of silicon from a 2.5-mm diameter sample in a solar nebula with PH2 ∼2 × 10−4 bar and to enrich the residual melt in heavy magnesium and silicon isotopes up to δ25Mg ∼5–10‰ and δ29Si ∼2–4‰. The expected chemical and isotopic features are compatible to those typically observed in coarse-grained Type A and B CAIs. Evaporation for ∼1 h will produce δ25Mg ∼30–35‰ and δ29Si ∼10–15‰, close to the values in highly fractionated Type F and FUN CAIs. These very short timescales suggest melting and evaporation of CAI precursors in very short dynamic heating events. The experimental results reported here provide a stringent test of proposed astrophysical models for the origin and evolution of CAIs.

Catechin Loaded Poly(lactic-co-glycolic acid) Nanoparticles: Characterization, Antioxidant and Cytotoxic Activity Against MCF-7 Breast Cancer Cells.

Here we evaluate the cytotoxic and antioxidant properties of Catechin (Cat) loaded nanoparticles (CatNps) on breast cancer cell lines. CatNps were prepared by the modified single emulsion solvent evaporation method. The structural, physical and chemical properties of the CatNps including PLGA-Cat interactions, and surface characteristics, were analyzed by dynamic light scattering (DLS), Fourier transform infrared (FT-IR), and Scanning Electron Microscopy (SEM). The average particle size of CatNps was 190.5±1.762 nm with an encapsulation efficiency of 10% and zeta potential value of 13.7±1.258 mV. The CatNps had reaction yield of 43.47±1.1% and loading capacity of 3.710±2.6% Treating MCF-7 cells with CatNps for 48 h led to a decrease in cell viability with an of IC50 22.59 μg/mL. The antioxidant behavior of CatNps was evaluated by the DPPH method in various pH environments (pH 3-, 6-, 7.4-, 9- and 12). Despite the low encapsulation efficiency, CatNps showed significant antioxidant efficacy against DPPH radicals relative to Cat. Our results revealed that CatNps could be used as promising anti-cancer agents due to their enhanced cytotoxic activity, increased bioavailability, and antioxidant properties.

Drug-encapsulated blend of PLGA-PEG microspheres: in vitro and in vivo study of the effects of localized/targeted drug delivery on the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is more aggressive and difficult to treat using conventional bulk chemotherapy that is often associated with increased toxicity and side effects. In this study, we encapsulated targeted drugs [A bacteria-synthesized anticancer drug (prodigiosin) and paclitaxel] using single solvent evaporation technique with a blend of FDA-approved poly lactic-co-glycolic acid-polyethylene glycol (PLGA_PEG) polymer microspheres. These drugs were functionalized with Luteinizing Hormone-Releasing hormone (LHRH) ligands whose receptors are shown to overexpressed on surfaces of TNBC. The physicochemical, structural, morphological and thermal properties of the drug-loaded microspheres were then characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Nuclear Magnetic Resonance Spectroscopy (NMR), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). Results obtained from in vitro kinetics drug release at human body temperature (37 °C) and hyperthermic temperatures (41 and 44 °C) reveal a non-Fickian sustained drug release that is well-characterized by Korsmeyer-Peppas model with thermodynamically non-spontaneous release of drug. Clearly, the in vitro and in vivo drug release from conjugated drug-loaded microspheres (PLGA-PEG_PGS-LHRH, PLGA-PEG_PTX-LHRH) is shown to result in greater reductions of cell/tissue viability in the treatment of TNBC. The in vivo animal studies also showed that all the drug-loaded PLGA-PEG microspheres for the localized and targeted treatment of TNBC did not caused any noticeable toxicity and thus significantly extended the survival of the treated mice post tumor resection. The implications of this work are discussed for developing targeted drug systems to treat and prevent local recurred triple negative breast tumors after surgical resection.

Formulation of PPAR-gamma agonist as surface modified PLGA nanoparticles for non-invasive treatment of diabetic retinopathy: in vitro and in vivo evidences

Diabetic retinopathy is one of the worst complications of diabetes and it is treated by invasive method. We prepared a surface modified poly (D, L-lactide-co-glycolide) i.e. PLGA nanoparticles for delivery of pioglitazone-a peroxisome proliferator-activated receptor-gamma agonist to posterior segment of the eye by topical administration. The present study investigated two grades of PLGA viz. 75:25 and 50:50. Surface modification was performed using polysorbate 80. Nanoparticles were prepared by single emulsion solvent evaporation method and optimized by using 3-factor 3-level Box-Behnken statistical design. Mean particle size, PDI and entrapment efficiency for optimized batch of PLGA 75:25 was found to be 163.23 nm, 0.286 and 91%, whereas; for PLGA 50:50 it was 171.7 nm, 0.280 and 93% respectively. DSC confirms the molecular dispersion of drug in polymer. In vitro release study showed biphasic drug release pattern with 58.48 ± 1.38% and 74.17 ± 1.38% cumulative drug release by PLGA 75:25 and 50:50 nanoparticles at the end of 10h. The release profile of pioglitazone from nanoparticles appeared to fit best with Higuchi model. In vivo study on rat showed dose dependent reduction in vascular endothelial growth factor concentration in vitreous fluid. The study reveals significance of peroxisome proliferator-activated receptor-gamma in management of diabetic retinopathy.

Innovative employing of salt hydration with adsorption to enhance performance of desalination and heat transformation systems

This study originally presents for the first time an idea that combines chemical and physical sorption for water desalination applications. It shows working principles of a hybrid salt hydrate/adsorption in a single water desalination system and presents a mathematical model for its performance. Three beds system has been considered employing high and low pressures evaporators. Different operating conditions like driving, cooling temperatures and cycle time of the system have been studied. The innovated hybrid system has two effective advantages over the known two beds adsorption desalination cooling system with a single evaporator. The first advantage is the proposed system has higher performance in terms of daily water production, cooling power and coefficient of performance by 56%, 55%, and 25% respectively. It also could be operated efficiently with a relatively low driving temperature (55 °C–65 °C) presenting a daily pure water of 8–9 m3/day·tonads where solar and/or waste energy can be used.

Water soluble polymer added high mass flux spray: A novel approach for the attainment of enhanced heat transfer rate in transition boiling regime

Although in the literature, the polyethylene glycol (PEG) added water dropwise evaporative cooling at very low temperature and single droplet evaporation mechanisms are revealed, the role of polyethylene glycol in spray evaporative quenching at very high initial surface temperature (900°C) has not been revealed so far. According to the reported information, PEG added water droplet evaporation favors high heat flux and therefore, in the current work, it is expected that by performing high mass flux polymer spray cooling at very high initial temperature, heat transfer rate can be augmented. The enhancement mechanism is based on the alteration of the surface properties in the favorable direction of heat transfer. The surface modification is achieved by adding water soluble polymer (Polyethylene Glycol) of different molecular weights (PEG 200 and PEG 600) as additives, which make the surface hydrophilic due to the deposition on the hot plate during evaporation. Before experimentation, the conditions and properties leading to the formation of coating were investigated by analyzing the polymer droplet wall interaction. This study depicts that due to the interaction of polymer with wall and very slow diffusive nature of polymer in water, the deposition of polymer is expected to occur during evaporation. The hydrophilic nature of the surface increases the spreading factor of the impinging droplet and this phenomenon increases heat transfer area, which in turn favors higher heat transfer rate. Spray evaporative cooling study was carried out on a hot AISI 304 steel plate using polymer solution of different concentrations as coolant and the enhancement intensity was identified by comparing with the result of pure water. The comparison illustrates significant enhancement i.e. 30% in CHF and 28% in IHF for 20 ppm concentration of polymer type I. For the verification of heat transfer mechanism and identification of the reason behind enhancement, different dimensionless numbers such as Reynold's number, Weber and Prandtl numbers were analyzed. The surface morphology of heat treated steel plate clearly indicates the deposition of the polymer over surface of the plate and the characteristics of the deposition confirm the superhydrophilic nature. In comparison with the literature, the developed coating on the surface of the plate is thermally, mechanically and chemically more stable.

Development of Resistant Starch Film Coated Microparticles for an Oral Colon‐Specific Drug Delivery

AbstractIn this study, novel enzymatically modified resistant starch type III (EM‐RSIII) derived drug loaded microspheres are developed for oral colon‐specific delivery of ciprofloxacin HCl, used as a model drug. EM‐RS III is enzymatically prepared using starch hydrolyzing enzymes amylase and pullulanase. The prebiotic effect of EM‐RSIII is successfully scrutinized for promoting the growth of probiotic bacteria, for example, Lactobacillus reuteri. Drug‐loaded microspheres are synthesized from the EM‐RSIII through a single emulsion evaporation method. The pH‐sensitive drug‐loaded microspheres are characterized through scanning electron microscopy, X‐ray diffraction, and Fourier‐transform infrared spectroscopy. Release studies confirm the stability of drug‐loaded microspheres at acidic pH while sustained release is observed at pH 7.8 demonstrating a site‐specific delivery of drug to the colon. The in vitro release mechanism of drug is evaluated using various kinetic models. The study also reveals that EM‐RSIII‐derived microspheres are biodegradable and are degraded by the natural microflora of the colon, which is indicated by stimulating growth of probiotic bacteria. The microspheres are exploited as drug carriers for the colon‐specific release of ciprofloxacin HCl, and its encapsulation is further confirmed from the antibacterial activity.

Performance comparison of a vertical direct expansion geothermal evaporator: Part I, single U-pipe using different refrigerants

Abstract CO2 is a promising candidate for replacing synthetic refrigerants used in direct-expansion ground-source heat pumps (DX-GSHPs). The present paper, as the first part of two, presents a numerical performance comparison of a vertical single U-pipe direct expansion geothermal evaporator using different refrigerants; namely R744, R410A, R22, R407C, R12345yf, and R134a. Each refrigerant was tested through a borehole heat exchanger (BHE) performance simulation at a constant rate of heat extraction. Operating parameters were chosen so that each refrigerant is subjected to a complete evaporation cycle, and a similar pressure drop from the inlet to outlet of the borehole. Several BHE parameters such as fluid temperature, pressure, mass flow rate, required pipe dimensions, and required power for fluid circulation were evaluated for different refrigerants. Finally, the overall performance of each refrigerant was characterized by the heat exchange capacity for a unit of mass flow rate and pipe surface area. Results showed that CO2 offers unique characteristics favoring the design of compact BHEs, as it required the smallest mass flow and pipe surface area. It is also concluded that the performance of a BHE with CO2 can be significantly improved through using unconventional configurations. This will be discussed further in the second part (PART II).

The battle against biofilm infections: juglone loaded nanoparticles as an anticandidal agent

In this study, juglone nanoparticles were prepared by single emulsion solvent evaporation method and their effect against Candida albicans biofilm was investigated in comparison with the free juglone and Fluconazole by performing XTT, crystal violet, standard plate count, confocal microscopy and membrane depolarization analyses. Juglone nanoparticles and free juglone were found to inhibit biofilm formation and pre-established biofilms (98-100%) at all doses tested, whereas Fluconazole did not cause a significant inhibition, even at the highest dose applied, especially against pre-established biofilms. Membrane depolarization analysis showed that free juglone and juglone loaded nanoparticles were effective on C. albicans membrane structure and have fluorescence quenching effect on DiSC3(5). It is extremely important that the antibiofilm activity of the juglone nanoparticles is similar to that of the juglone used at the same concentration, since similar effect is provided by using less active substance due to controlled release. Accordingly, it can easily be said that juglone loaded nanoparticles are much more effective in the formation and elimination of C. albicans biofilm than the free juglone and Fluconazole.

Effect of Vacuum Insulation Panels on Energy Consumption and Thermal Load Transfer between Compartments in a Three-Temperature Frost-Free Refrigerator

The three-temperature frost-free refrigerator is popular in China currently, which adopts a single evaporator and separate air ducts to distribute cold air into all compartments, i.e., the fresh food compartment (FFC), the variable temperature compartment (VTC), and the freezer compartment (FZC). Two identical refrigerators with cyclopentane insulation are comparatively studied in this article, one with vacuum insulation panels (VIPs) in two sidewalls and the other without. Results show that VIPs reduce the steady-state energy consumption of the refrigerator by 12.4% due to smaller average power input and longer compressor-off duration. The decrease in average power input originates from a shorter FFC-damper-on duration since VIPs reduce its thermal load. However, the FFC average temperature rises unexpectedly with shorter damper-on and longer damper-off durations, and induces thermal load transfer from FFC to FZC through the mixing of return air in the evaporator chamber. Consequently, FZC-only duration increases and compensates for the decrease in FFC-damper-on duration, resulting in an overall similar compressor-on duration. Simulation results of the heat transfer process through the evaporator are also provided in both cases to obtain a full view of the thermal load transfer process.

Quercetin-loaded nanoparticles enhance cytotoxicity and antioxidant activity on C6 glioma cells

Quercetin (Qu) is a natural flavonoid present in many commonly consumed food items. The dietary phytochemical quercetin prevents tumor proliferation and is a potent therapeutic cancer agent. The purpose of this study was to synthesize and characterize quercetin-loaded poly(lactic-co-glycolic acid) nanoparticles (Qu1NP, Qu2NP, and Qu3NP) with different size and encapsulation properties and to evaluate their in vitro activity on C6 glioma cells. Nanoparticles were synthesized by single emulsion solvent evaporation method. Then, particle size, zeta potential, polydispersity index and encapsulation efficiency of nanoparticles were determined. Particle size of Qu1NP, Qu2NP, and Qu3NPs were determined as 215.2 ± 6.2, 282.3 ± 7.9, and 584.5 ± 15.2 nm respectively. Treating C6 glioma cells with all nanoparticle formulations effectively inhibited the cell proliferation. Qu1NPs were showed the lowest IC50 value in 48 h with 29.9 μg/ml and achieved higher cellular uptake among other nanoparticles and Qu. Additionally, 48-h treatment with Qu1NPs significantly decreased MDA level (14.90 nmol/µg protein) on C6 glioma cells which is related to reduced oxidative stress in cells. Findings of this study revealed that quercetin’s cellular uptake and anti-oxidant activity is improved by small-sized Qu1NPs in C6 glioma cells.

Optimization of in-situ Nanoparticulate Gel of Ofloxacin using Factorial Design to Improve Treatment Strategy for Conjunctivitis and Corneal Ulcers

Abstract: Background: One of the main problems in ophthalmic drug delivery is the rapid elimination of conventional liquid eye drops from the eye due to rapid tear turnover resulting precorneal loss because of irritation caused by the drug preparation from large volume of the administered eye drop (~50 μl), a very small amount i.e. <5% of the dosage actually penetrates and is able to reach intraocular tissues. Ofloxacin (OFL), a fluoroquinolone drug is used for the treatment of conjunctivitis and corneal ulcers and it is given quarterly in a day because its bioavailability is very low. The present study was designed to increase the ocular residence time of drug by formulating nanoparticulate in-situ gel for ensuring low irritation, better release and compatibility with ocular tissue. Materials and Methods: Initially, OFL nanoparticles were prepared using single emulsion solvent evaporation method and evaluated for various evaluation parameters. Based on the results, an optimized batch (B3) was selected by applying factorial design; which was further converted into in-situ gel. Results: Results of evaluation parameters revealed that optimized batch (B3) showed significant (p=0.0001 and p=0.0090) increased in particle size and entrapment efficiency in comparison to rest batches. Moreover, nanoparticulate in-situ gel showed satisfactory results. Conclusion: Hence, Ofloxacin nanoparticulate in-situ gel thus formulated showed controlled drug release with lesser dosing frequency. Key words: Ofloxacin, Nanoparticle(s), Nanoparticulate in-situ gel, Conjunctivitis, Factorial design.