A brand new green coating technology for realizing the regulation of spherical propellant energy release process

To achieve the controllable release of energy of nitrocellulose-based propellants,this paper combines the cellulose-based nanocomposites aqueous coating(Surelease®-NC)with fluidized bed coating equipment to successfully prepare the coated spherical propellant for the first time.The effects of fluidized bed coating temperature,air velocity,flow speed and atomization pressure on the adhesion rate,coating integrity and coating uniformity of the coated spherical propellant were investigated,and the preparation of coated spherical propellant with homogeneous size and structural integrity was achieved for the first time.The microscopic morphology,chemical structure,water vapor adsorption behavior,combustion performance,and ageing resistance property of the coated spherical propellant were systematically investigated by,Fourier transforms infrared spectroscopy(FTIR),Micro confocal raman spectrometer,field scanning electron microscopy(SEM),dynamic vapor adsorption techniques,and closed bomb test,confirming the surface core-shell structure and the tightly bonded interfacial structure of coated spherical propellant.Meanwhile,the coated spherical propellant has good hygroscopic,excellent progressive burning and long storage stability.

Tailoring Iron-Ion Release of Cellulose-Based Aerogel-Coated Iron Foam for Long-Term High-Power Microbial Fuel Cells

The presence of iron(Fe) has been found to favor power generation in microbial fuel cells(MFCs). To achieve long-term power production in MFCs, it is crucial to effectively tailor the release of Fe ions over extended operating periods. In this study, we developed a composite anode(A/IF) by coating iron foam with cellulose-based aerogel. The concentration of Fe ions in the anode solution of A/IF anode reaches 0.280 μg/mL(Fe^(2+) vs. Fe^(3+) = 61%:39%) after 720 h of aseptic primary cell operation. This value was significantly higher than that(0.198 μg/mL, Fe^(2+) vs. Fe^(3+) = 92%:8%) on uncoated iron foam(IF), indicating a continuous release of Fe ions over long-term operation. Notably, the resulting MFCs hybrid cell exhibited a 23% reduction in Fe ion concentration(compared to a 47% reduction for the IF anode) during the sixth testing cycle(600-720 h). It achieved a high-power density of 301 ± 55 mW/m^(2) at 720 h, which was 2.62 times higher than that of the IF anode during the same period. Furthermore, a sedimentary microbial fuel cell(SMFCs) was constructed in a marine environment, and the A/IF anode demonstrated a power density of 103 ± 3 mW/m^(2) at 3240 h, representing a 75% improvement over the IF anode. These findings elucidate the significant enhancement in long-term power production performance of MFCs achieved through effective tailoring of Fe ions release during operation.

Coating Process of Paeonol Sustained Release Pills

[Objectives] To study the coating process of paeonol sustained release pills by extrusion-spheronization method taking ethyl cellulose as the coating material. [Methods] Paeonol pills were made by Auari AW-95 Full Automatic Pill Making Machine. Coating of paeonol sustained release pills was prepared by Auari Mini Pill Polishing Machine. The prescription and process factors of paeonol sustained release pills coating were investigated by single factor experiment and orthogonal experiment. The release of paeonol sustained release pills was determined according to the cumulative release curve of paeonol. [Results] The prepared paeonol sustained release pills released slowly within 24 h, and the release rate reached 80% in 12 h. [Conclusions] The prepared paeonol sustained release pills basically meet the 24 h sustained release standard, and can be further developed and applied.

Release rate kinetics of corrosion inhibitor loaded halloysite nanotube-based anticorrosion coatings on magnesium alloy AZ91D

Halloysite nanotubes were used as nanocontainers to hold corrosion inhibitors such as Ce^(3+)-Zr^(4+),2-mercaptobenzothiazole and 8-hydroxyquinoline in their lumen.An acid assisted etching of the nanotubes was carried out with a view to increase the lumen diameter and thereby,increase the amount of loading of the corrosion inhibitor.The morphology of as-received and etched halloysite nanotubes was ob-served using TEM analysis.The loading of corrosion inhibitors was confirmed using SEM-EDS and BET analysis.Polymeric microcapsules were used as capping agents for the ends of the loaded HNTs following which,they were dispersed into a hybrid sol-gel silica matrix.Dip coating method was used to generate coatings on AZ91D substrates followed by heat treatment at 130℃ for 1 h.The release rate kinetics of corrosion inhibitors from as-received and etched nanotubes was investigated in buffer solutions of 3.5 wt%NaCl at different pH.The release mechanism of corrosion inhibitors from the HNT lumen was validated using various semi-empirical models.Coatings were also evaluated for their corrosion protection ability using electrochemical techniques after exposure to 3.5 wt%NaCl solution for 120 h.Coatings generated using Ce^(3+)-Zr^(4+)loaded into as-received halloysite nanotubes have shown more effective corrosion protection when compared to other corrosion inhibitors after 120 h exposure to the corrosive medium.

Controlling Bovine Serum Albumin Release From Biomimetic Calcium Phosphate Coatings

Biomimetic calcium phosphate (CaP) coating has been used successfully for protein delivery, but the release of protein from CaP coating is mainly dependent on the limited dissolution of the CaP coating and the passive diffusion of the protein in the CaP coating. In the present work, our aim is to improve the release behavior of protein from CaP coating and make it more controllable. By using bovine serum albumin (BSA) as a model protein, our strategy is to tailor BSA release profiles by controlling the distribution of BSA in CaP coatings. To achieve this aim, BSA was added to a modified simulated body fluid (m-SBF) at different stages of coating formation to obtain tailored BSA release profiles. Sustained BSA release was obtained when BSA was added to m-SBF at the initial stage of the coating where the BSA was incorporated into the lattice structure of the coating. In contrast, a relatively faster release was observed when BSA was added during the later stage of coating formation where BSA was mainly adsorbed to the coating surface. As a result, the BSA release efficiency could be tailored by adding BSA into m-SBF at different coating formation stages. More importantly, the coating composition was not altered with the change of BSA adding times and all the beneficial properties of the biomimetic coating were reserved. Therefore, the BSA release from CaP coatings can be tailored by adjusting its distribution in the coating to achieve a more satisfactory release profile.

Shifts in soil bacterial communities induced by the controlled-release fertilizer coatings

Coated controlled-release fertilizers （CRFs） have been widely applied in agriculture due to their increased efficiency. However, the widespread and a lot of coated CRFs application may leave undesired coating residues in the soil due to their slow degradation. Limited information is available on the effects of substantial residual coatings on the soil bacterial community. By adding 0, 5, 10, 20, and 50 times quantities of residual coating from conventional application amount of resin and water-soluble coated CRFs, we studied the responses of soil properties and bacterial community composition to these two residual coatings in black soil. The results showed that the resin and water-soluble coatings did not essentially alter the properties of black soil or cause dramatic changes to bacterial diversity within the test concentration range. The residual resin and water-soluble coatings also did not distinctly alter the relative abundance of the top ten bacteria at phylum level. Heatmap results suggested that the treatments were basically clustered into two groups by concentration rather than types of coating material. Pearson correlation analysis showed that the Simpson＇s diversity index of the bacterial community was significantly correlated with microbial biomass carbon （MBC, r=0.394, P〈0.05）, and the richness index abundance-based coverage estimator （ACE） of the bacterial community was significantly correlated with microbial biomass nitrogen （MBN, t=0.407, P〈0.05）. Overall, results of this study suggested that substantial residual resin and water-soluble coatings with 0-50 times quantities of residual coating from conventional application amount of coated CRFs did not generate obviously negative impacts on the bacterial community in black soil.

Study on Release Properties of Slow Release Urea Coated by Industrial Lignin

This study aimed to investigate the release properties of slow release ure- a coated by industrial lignin and the influences of temperature, pH and post-ripening period on the release of nutrients in coated urea. According to the experimental results, the release of nutrients in coated fertilizers showed an S-shaped curve; on the 28th d, the nutrient release rate reached 73.77%; the differential solubility was 1.83%, and the theoretical release period was 50.25 d. The release of nutrients was significantly influenced by temperature. As the incubation temperature rose from 25 to 40 ℃, preliminary solubility increased from 8.03% to 16.24%; differential solubility increased from 1.83% to 1.88%; theoretical release period was reduced from 51.25 d to 45.55 d. The release of nutrients was promoted by H＋ and OH-. After they were placed at room temperature within 30 d, coated fertilizers exhibited the optimal release properties.

Synthesis and Performance of Polyurethane Coated Urea as Slow/controlled Release Fertilizer

Polyurethane coated urea slow/controlled release fertilizer was prepared based on urea granules, isocyanate, polyols and paraffin. Isocyanate reacted with polyols to synthesize the polyurethane skin layer on urea granules surface. Paraffin serves as a lubricant during syntheses of polyurethane skin layers. The structure and nutrient release characteristics of the polyurethane skin layers were investigated by FTIR, SEM and TG. Urea nitrogen slow-release behavior of the polyurethane coated urea was tested. The experimental results indicated that compact and dense polyurethane skin layers with a thickness of 10-15 lam were formed on urea surface, the urea nitrogen slow-release time can reach 40-50 days. Paraffin proves to play a key role in inhibiting water to penetrate into urea, but excessive addition would decrease the polyurethane crosslinking density.

Study on the Rapid Method to Predict Longevity of Controlled Release Fertilizer Coated by Water Soluble Resin

The study discussed the rapid method to test and predict the longevity of controlled release fertilizers （CRFs） coated by water soluble resin by using the short-term leaching under higher temperature. Pure water dissolving incubation and higher temperature leaching were used to study the patterns of the nutrient release of the CRFs. The correlation analysis between the days at 25℃ and the hours at 80℃ of Trincote 1 and Trincote 2 for the same cumulative release rates were conducted. Patterns of cumulative nutrient release curve followed one factor quadratic regression equation at each given temperatures, and each of relative coefficient was bigger than 0.995. As the temperature increased, nutrients release of the CRFs increased. The longevity of resin coated CRFs were predicted by use of both the cumulative nutrients release equation at 80℃ and the regression equation of release time needed for the same cumulative release rates between 25 and 80℃. There were only 0.3-6.9% relative errors between the tested longevity and predicted one. In conclusion, the longevity of resin coated CRFs could be predicted more quickly and precisely by use of the higher temperature short-term leaching method than that of the traditional differential release rate. The longevity of resin coated CRF could be rapidly and precisely predicted in a few hours by application of the higher temperature shortterm leaching method.

THE DRUG RELEASE FROM A COATED PLANAR MATRIX WITH A SUB-SATURATION LOADING IN THE CORE

A model was proposed for the drug release from a coated matrix system.To validate thismodel,5-Fu/EVAL matrices coated with various polymeric materials with different diffusivities wereprepared and characterized.These coated systems were experimentally investigated and graphically andquantitatively compared with theoretical values.The results show a good correlation between theoryand experiment.

Enhanced delivery efficiency and sustained release of biopharmaceuticals by complexation-based gel encapsulated coated microneedles:rhIFNα-1b example

Coated microneedles(MNs) are widely used for delivering biopharmaceuticals. In this study, a novel gel encapsulated coated MNs(GEC-MNs) was developed. The water-soluble drug coating was encapsulated with sodium alginate(SA) in situ complexation gel. The manufacturing process of GEC-MNs was optimized for mass production. Compared to the water-soluble coated MNs(72.02% ± 11.49%), the drug delivery efficiency of the optimized GEC-MNs(88.42% ± 6.72%) was steadily increased, and this improvement was investigated through in vitro drug release. The sustained-release of BSA was observed in vitro permeation through the skin. The rhIFN α-1 b GEC-MNs was confirmed to achieve biosafety and 6-month storage stability. Pharmacokinetics of rhIFN α-1 b in GEC-MNs showed a linearly dosedependent relationship. The AUC of rhIFN α-1 b in GEC-MNs(4.51 ng/ml ·h) was bioequivalent to the intradermal(ID) injection(5.36 ng/ml ·h) and significantly higher than water-soluble coated MNs(3.12 ng/ml ·h). The rhIFN α-1 b elimination half-life of GEC-MNs, soluble coated MNs, and ID injection was 18.16, 1.44, and 2.53 h, respectively. The complexation-based GECMNs have proved to be more efficient, stable, and achieve the sustained-release of watersoluble drug in coating MNs, constituting a high value to biopharmaceutical.

A Rapid Technique for Prediction of Nutrient Release from Polymer Coated Controlled Release Fertilizers

Controlled release fertilizers (CRF) are produced with different rates and durations of nutrient release to cater to different crops with wide ranges of nutrient requirements. A rapid technique is needed to verify the label specifications of nutrient release rate and duration. Polymer-coated urea (PCU) (43% nitrogen [N]) and polymer-coated N, phosphorus (P), potassium (K) (PC_NPK;14-14-14) fertilizer products were used in this study. Soil incubation of the above CRF products at 25℃ showed that 63.6% to 70.8% of total N was released over 220 days (d). At 100℃ in water 100% of N release occurred in about 168 to 216 hours (h). Regression equations were developed for cumulative nutrient release as a function of release time separately at 25℃ and 100℃. Using the above regressions, the release duration for a given percent nutrient release at each temperature was calculated. These values were then used to establish a relationship between the release duration at 25℃ as a function of that at 100℃. This relationship is useful to predict the release duration at 25℃ of an unknown CRF product by conducting a rapid release test in water at 100℃. This study demonstrated that a rapid nutrient release test at 100℃ successfully predicted nutrient release rate and duration at 25℃, for polymer coated fertilizers. Therefore, this rapid test can be used to verify the label release rate and duration of most CRF products.

The Production of Organic-Inorganic Compound Film-Coated Urea and the Characteristics of Its Nutrient Release

The effect of different concentrations of natural macromolecular compound on the characteristics of nutrient release in the membrane materials of organic-inorganic compound film-coated urea was discussed, and the optimal concentrations for better nutrient release was proposed. The characteristics of nutrient release of film-coated urea were evaluated by soil column leaching experiment. Organic-inorganic compound film-coated urea showed good characteristics of nutrient release, which could be well simulated by Logistic curve. The two parameters in this curve, a and r, can be used to present nutrient release of film-coated urea, and followed the order of B 〉 C 〉 A and C 〈 B 〈 A, respectively, indicating that the release was stronger with the increasing concentration of natural macromolecular compound in the membrane, which implied better controllability of nutrient release. The concentration of 5% of natural macromolecular compound showed better characteristic of nutrient release and can be utilized as a membrane material combined with inorganic mineral powders to develop film-coated slow-release fertilizer.

Tablets of paliperidone using compression-coated technology for controlled ascending release

The aim of this work was to prepare ascending release compression-coated(CC) tablets with paliperidone(PAL) using a simple manufacturing technique and short manufacturing process.The release behavior and mechanisms in vitro of the final tablets was investigated and evaluated. The PAL CC tablets were comprised of a core layer of high viscosity hydroxypropyl cellulose(HPC-H) and a coating layer of high viscosity hydroxypropyl methylcellulose(HPMCK100 M). Several factors such as materials and core tablet compositions were studied for their influence in the formulation procedure. The drug release mechanism was studied using gravimetric analysis. The data could be fitted to the Peppas model. The ascending drug release results were expressed in terms of the slope of the release curve at different time points.Results showed that the formulation could achieve a good ascending drug release when the weight ratio of PAL was 5:1(core:layer). The fraction of HPC and HPMC was 33 %, and the combination of Eudragit RL-PO was 10%. The ascending release mechanism was due to solvent penetration into the PAL CC tablets, and subsequent drug dissolution from the gelatinous HPC and HPMC matrix erosion. The release mechanism was therefore a combination of diffusion and erosion. This work demonstrated that the compression-coated tablets could achieve controlled ascending release over 24 h for the oral administration systems.

Release Kinetics of Urea from Polymer Coated Urea and Its Relationship with Coating Penetrability

Four kinds of polymer coated urea(PCU)were put in distilled water at 30℃ to determine the variation of coating penetrability and give a precise description of the urea release kinetics. The urea release from PCU could be divided into four stages: lag stage, swell stage, steady stage and decay stage. The release rate coefficient K, a measure of coating penetrability, was linearly increased at swell stage, but almost not variable at steady stage. At decay stage, the relation of X to time t could be described by the equation K= mtn-1where m and n are the coefficients). When n>1, the coating penetrability was gradually increased, and the urea release from PCU was accelerated; when n=1, the coating penetrability was steady, and the urea release from PCU obeyed the first-order kinetics; and when n<1.the coating penetrability was gradually decreased, and the urea release from PCU was delayed, resulting in a significant 'tailing effect'.

Study on Membrane Microstructures and Characteristics of Infrared Spectra and Nitrogen Release of Solid-Liquid Reaction Coated Urea

The membrane microstructures and the mechanism of two coated ureas formed through solid- liquid reaction were observed by scanning electron microscope and infrared spectra, the relation of the structural characteristics with the nitrogen release feature was also discussed by combining with nitrogen dissolution in water. The results showed that the membranes were made of solid particles tightly connected to each other and were piled up layer by layer through liquid glue. Porosity and aperture of membrane were determined by compactness of piled layers and the particles in a single layer and also related to the characteristics of coating materials. Research of the infrared spectra of membrane, made of a solid powder and a liquid glue, proved that O-H on the solid surface was bonded with the double bond of the liquid glue, thus forming membrane and keeping it stable. It was found that the two coated ureas showed obvious differences in nitrogen releasing due to their membrane structures, the porosity and aperture of membrane were the critical factors for nitrogen releasing.

Impact of Biomechanical Forces on Antibiotics Release Kinetics from Hydroxyapatite Coated Surgical Fixation Pins

This work investigates the impact of biomechanical wear and abrasion on the antibiotic release profiles of hydroxyapatite (HA) coated fixation pins during their insertion into synthetic bone. Stainless steel fixation pins are coated with crystalline TiO2 by cathodic arc evaporation forming the bioactive layer for biomimetic deposition of Tobramycin containing HA. Tobramycin is either introduced by co-precipitation during HA formation or by adsorption-loading after HA deposition. The samples containing antibiotics are inserted into bone mimicking polyethylene foam after which the drug release is monitored using high performance liquid chromatography. This analysis shows that HA coating wear and delamination significantly decrease the amount of drug released during initial burst, but only marginally influence the sustained release period. Spalled coating fragments are found to remain within the synthetic bone material structure. The presence of HA within this structure supports the assumption that the local release of Tobramycin is not only expected to eliminate bacteria growth directly at the pin interface but as well at some distance from the implant. Furthermore, no negative effect of gamma sterilization could be observed on the drug release profile. Overall, the observed results demonstrate the feasibility of a multifunctional implant coating that is simultaneously able to locally deliver clinically relevant doses of antibiotics and an HA coating capable of promoting osteoconduction. This is a potentially promising step toward orthopaedic devices that combine good fixation with the ability to treat and prevent post-surgical infections.

Investigation of the Release of Particles from a Nanocoated Product

Manufactured products are being coated with nanoparticles in order to functionalize them with antibacterial or self-cleaning properties or to improve their durability etc. As the (eco-) toxicological effects of the nanoparticles are not well known yet, their use could lead to new potential risks for the workers, the consumers and the environment. This study focuses on the release of the nanoparticles during the operations related to the handling and processing of an automotive part. The part is made up of a metallic alloy and, in order to reduce friction, the part is nano-coated with inorganic fullerenes. The mechanical stresses appearing during these operations are reproduced in a nano-secured facility. The release of nanoparticles is found to be increasing with the wear energy applied on the surface.

Study the effect of formulation variables in the development of timed-release press-coated tablets by Taguchi design

In this investigation, the effect of formulation variables on the release properties of timed- release press-coated tablets was studied using the Taguchi method of experimental design. Formulations were prepared based on Taguchi orthogonal array design with different types of hydrophilic polymers (X1), varying hydrophilic polymer/ethyl cellulose ratio (X2), and addition of magnesium stearate (X3) as independent variables. The design was quantitatively evalu-ated by best fit mathematical model. The results from the statistical analysis revealed that factor X1, X3 and interaction factors between X1X2 and X1X3 were found to be significant on the re-sponse lag time (Y1), where as only factor X1 was found to be significant on the response percent drug release at 8 hrs (Y2). A numerical optimization technique by desirability function was used to optimize the response variables, each having a different target. Based on the re-sults of optimization study, HPC was identified as the most suitable hydrophilic polymer and incorporation of hydrophobic agent magnesium stearate, could significantly improve the lag time of the timed-release press-coated tablet.

One-Step Preparation of Poly-Lactic-Co-Glycolic-Acid Microparticles to Prevent the Initial Burst Release of Encapsulated Water-Soluble Proteins

An initial burst is often observed during the release of active pharmaceutical ingredients (APIs) from poly-lactic-coglycolic-acid (PLGA) microparticles (MPs) which have been prepared by the emulsion-solvent evaporation method. Herein, we describe the development of a simple one-step coating method that suppresses the initial burst release process. This new method involves coating the PLGA-MPs with PLGA, with the coating process being performed through the phase separation of PLGA on the surface of PLGA-MPs using the emulsion-solvent evaporation method. Bovine serum albumin (BSA) was encapsulated in the PLGA-MPs as a model API. The coated MPs were spherical in shape with no pores on their smooth surface, whereas the non-coated PLGA-MPs had porous surfaces. An in vitro release study showed that the residual levels of BSA in the coated and non-coated PLGA-MPs after 1 h were about 99% and 16% of the original loads, respectively. The one-step coating method therefore represents a useful method for preparing PLGA-MPs that do not give an initial burst release of proteinaceous APIs.