Disintegration Rate Research Articles

Comparative assessment of in vitro/in vivo performances of orodispersible electrospun and casting films containing rizatriptan benzoate

The electrospinning process is a promising approach to produce various drug-loaded orodispersible films (ODFs) with a rapid onset of their actions. However, there is only limited number of studies comparing the pharmacological performances of electrospun ODFs (eODFs) with traditional casting films (CFs). In this study, rizatriptan benzoate (RB), a pain relieving agent was formulated with PVP and PVA into ODFs using electrospinning and casting methods. The ODFs were subsequently characterized with respect to their morphology, solid state properties and mechanical characteristics. The uniformity of the dosage units, disintegration behavior and dissolution patterns of the ODFs were also evaluated prior to the pharmacokinetic study. The obtained CFs and eODFs were semitransparent and white in appearance, respectively. The scanning electron microscopy revealed that the eODFs contained nanoporous structure, while the CFs showed no observable pores. RB was amorphously dispersed in both these films without drug-polymer interactions. The uniformity of dosage units for both eODFs and CFs was complied with European Pharmacopeia. As compared to the CFs, the eODFs were more flexible and lesser rigid in nature and showed faster disintegration and dissolution rates. In addition, the eODFs exhibited a higher bioavailability with a shorter Tmax relative to the CFs and commercial RB tablets. This study demonstrated that eODFs were superior to CFs with respect to in vivo pharmacological effects, which could be attributed to the submicron structure of eODFs obtained through the electrospinning process.

Impact Of Defensive Covering Of Anti-Inflamatory Medicine Tablets With Acrylatemethacrylate Copolymers On Tablet Crumbling Times And Disintegration Rates

Tablets of headache medicine (a dampness degradable medication) have been film covered with two undifferentiated from Eudragit RL and RS copolymers assigned here as An and B which vary just in their cation content in the proportion 2:1 (A:B). An, is in this manner more hydrophilic than B. The tablets were film covered with ethanol arrangements of these two polymers. Film covering with either An or B fundamentally decreased the dampness take-up possibilities of the tablets however caused an expansion in the breaking down occasions of the tablets and hindered disintegration rates. The mean deterioration times were 0.5±0.1 min (uncoated tablets), 16±2.5 min (tablets covered with An) and 115±3.6 min (tablets covered with B). The relating disintegration rates % h - 1 were 28.3 for uncoated, 16.6, covered with An and 14.8, covered with B, separately. Subsequently, covering with polymer B impressively impeded the crumbling and disintegration properties of the tablets.

Quality evaluation and UV spectrophotometric assay of ten brands of amlodipine tablets marketed in Uyo, Nigeria

Amlodipine is a calcium channel blocker that is widely used to treat hypertension, which is a chronic health condition characterized by persistent elevated pressure of blood in the arteries. Hypertension is a predisposing factor to stroke, kidney failure, heart diseases and vision loss. The large demand for amlodipine makes it a good candidate for fakers. Consumption of substandard and/or fake amlodipine tablets will have a negative impact on the management of hypertension. This justifies continuous monitoring of amlodipine preparations in the marketplace and the provision of simple and cost-effective assay method that could be routinely utilised for their assay. Ten different brands of amlodipine tablets were qualitatively assessed for uniformity of weight, friability, hardness, disintegration and dissolution rate using standard physical methods. Quantitative assay was carried out using spectrophotometric method. The spectrophotometric measurement was done at a wavelength of 240 nm. Seven brands met the official requirements for uniformity of weight; eight passed the friability test and the hardness tests. All the brands tested passed the disintegration test and nine brands passed the dissolution test. The spectrophotometric assay showed that all the brands passed the United States Pharmacopoeia (USP) requirement for percentage drug content. The assay method used in this study is reliable, simple and cost- effective and can be routinely used to assay amlodipine tablets.
 Keywords: Amlodipine, qualitative, quantitative, assay, ultraviolet spectrophotometry

The effects of freeze-thaw cycles at different initial soil water contents on soil erodibility in Chinese Mollisol region

Freeze-thaw action is a common natural phenomenon in cold regions, which affects soil erodibility by changing soil structure and mechanical properties. However, quantifying the impacts of freeze-thaw cycles (FTCs) at different initial soil water contents (ISWCs) on soil erodibility is challenging due to the complex interactive soil mechanical responses. In this study, direct shear strength and soil disintegration tests were conducted to quantify soil erodibility indices. Seven FTCs (0, 1, 3, 5, 7, 10 and 13) and three ISWCs (16.5, 24.8 and 33.0%) were employed to investigate soil shear behavior and disintegration properties for two Mollisol soils. Results showed that repeated FTCs had cumulative impacts on soil mechanical properties, and the 10th FTCs might be the threshold number for influencing soil erodibility. The soil shear strengths decreased by 1.1–15.1% and 9.2–30.5% under four normal stresses at the first and 13th FTCs, respectively, for these two soils. Soil cohesion generally decreased with the increase of FTCs. Soil internal friction angle showed no trend with FTCs at the 16.5% and 24.8% water contents but a decreasing trend at the 33.0% water content. Soil disintegration rate increased with FTC and reached a maximum value at the 10th cycle but decreased with the increase of ISWC. Soil disintegration of the two Mollisols showed a sharp disintegration of about 60% in 133 s. This study provides a new understanding of the response of erodibility to freeze-thaw conditions for two Mollisols.

PD15-02 THE EFFECT OF ALTERNATING BIDIRECTIONAL APPROACH DURING SHOCK WAVE LITHOTRIPSY FOR UPPER LUMBAR URETERIC STONES. A RANDOMIZED CONTROLLED TRIAL

INTRODUCTION AND OBJECTIVE: to compare the outcome of shock wave lithotripsy (SWL) for upper lumbar ureteric stones using the alternating bidirectional approach versus the standard approach during the first session. METHODS: Our study was a randomized controlled trial (NCT03243682) including patients with single radio-opaque upper lumbar ureteric stone less than 1cm. SWL was conducted using electromagnetic Dornier Gemini Lithotripter. In group1, patients were treated with the alternating under and over-table approach during the first session only and if another one or more sessions were needed, the standard under-table approach was used. In group 2, patients were treated with the standard under-table approach during all sessions. The efficacy of stone disintegration after the first session was assessed by kidney-ureter-bladder (KUB) x-ray, renal ultrasonography (US). Noncontrast computed tomography was done for patients with no residual detected by KUB and US. Stone disintegration was classified as no (no change from basal by KUB X-ray or US imaging), partial (fragmented and >4-mm residual fragments), and complete (≤4-mm residual fragments). The incidence and severity of complications were evaluated. RESULTS: Forty eight patients in each group with comparable demographics and stone characteristics (table 1). Complete disintegration was achieved in 41.7% of patients in group 1 versus 18.8% in group 2 (p=0.021), while stone-free rate was 58.3% and 20.8% in group 1 and 2 respectively (p=0.001) (table 2). Stone length and width ≥8.5 mm and stone density ≥1135 HU significantly indicate disintegration failure in alternating bidirectional approach. CONCLUSIONS: For upper lumbar ureteric stones, stone disintegration and stone-free rate after the first SWL session are higher when using the alternating bidirectional approachSource of Funding: No

DEVELOPMENT OF THE COMPOSITION AND TECHNOLOGY FOR THE PRODUCTION OF ENCAPSULATED DRUGS BASED ON 3,7-DIAZABICYCLO[3.3.1]NONANE

The following biological and pharmaceutical factors influence the therapeutic efficacy and bioequivalence of drugs: physicochemical properties of a pharmaceutical substance, bioavailability, type of dosage form, route of administration, nature of excipients, their compatibility, as well as technological conditions of production, including the preparation of drugs forms. Before mass production of a drug, the technological parameters and characteristics of the pharmaceutical substance must be carefully studied and scientifically substantiated. This work is devoted to the study of the technological properties of an original pharmaceutical substance based on the derivative of 3.7-diazabicyclo[3.3.1]nonane with the chemical name IUPAC 6-[4methoxy-3- (1H-pyrazol-1-ylmethyl) benzyl] -1,11dimethyl-3,6,9-triazatricyclo[7.3.1.1]tetradecane-4,8,12-trion, used as an active substance for the development of the composition and technology for the preparation of oral dosage forms in capsule form. The article presents the results of the development and testing of a drug in the form of capsules of the original pharmaceutical substance of the nootropic action of 3,7-diazabicyclo[3.3.1]nonanane, which is practically insoluble in water. The study identified and evaluated the technological and biological properties of a pharmaceutical substance that can affect the pharmacological activity in the production of a dosage form. The study examined the key indicators: solubility, particle size, flowability, bulk density. The technological characteristics of the pharmaceutical substance are studied not only by certain values of the indicated characteristics but also by the values of the Hausner and Carr indices. The data obtained suggest the content and progress of further stages of pharmaceutical development. The presence of the lag phase when dissolving hypromellose capsules in a medium with a pH of 1,2 and relatively low disintegration rates in media with a pH of 1,2, pH 4,5, and pH 6,8 served as the basis for the choice of gelatin capsules. The developed dosage form meets modern pharmacopoeial requirements, including the dissolution kinetics: according to the results obtained, in 45 minutes (77,6 ± 2,5)% of the substance passes into the dissolution medium with a pH of 4,5. The results of the study are used to develop a technological scheme for obtaining the dosage form of 3,7-diazabicyclo[3.3.1]nonane, its indicators, and quality standards.

Modification of collagen-based sponges can induce an upshift of the early inflammatory response and a chronic inflammatory reaction led by M1 macrophages: an in vivo study

BackgroundThe present study evaluated the cellular tissue reaction of two equine-derived collagen hemostatic sponges (E-CHS), which differed in thickness after pressing, over 30 days in vivo. The inflammatory response during physiological wound healing in sham-operated animals was used as control group.Material and methodsFirst, the E-CHS was pressed by applying constant pressure (6.47 ± 0.85 N) for 2 min using a sterile stainless-steel cylinder until the material was uniformly flattened. Consequently, the original (E-CHS), the pressed (P-E-CHS), as well as the control group (CG; sham operation) were studied independently. The 3 groups were evaluated in vivo after subcutaneous implantation in Wistar rats during 3, 15, and 30 days. Histochemical and immunohistochemical methods provided observations of biomaterial degradation rate, cellular inflammatory response, and vascularization pattern. A derivative of human blood known as platelet-rich fibrin (PRF) was used as an ex vivo model to simulate the initial biomaterial-cell interaction. Segments of E-CHS and P-E-CHS were cultivated for 3 and 6 days with PRF, and the release of pro-inflammatory proteins was measured using ELISA. PRF cultivated alone was used as a control group.ResultsAt day 3, the CG induced a statistically significant higher presence of monocytes/macrophages (CD68+), pro-inflammatory macrophages (M1; CCR7+), and pro-wound healing macrophages (M2; CD206+) compared to E-CHS and P-E-CHS. At the same time point, P-E-CHS induced a statistically significant higher presence of CD68+ cells compared to E-CHS. After 15 days, E-CHS was invaded by cells and vessels and showed a faster disintegration rate compared to P-E-CHS. On the contrary, cells and vessels were located only in the outer region of P-E-CHS and the biomaterial did not lose its structure and accordingly did not undergo disintegration. The experimental groups induced similar inflammatory reaction primarily with positive pro-inflammatory CD68+/CCR7+ macrophages and a low presence of multinucleated giant cells (MNGCs). At this time point, significantly lower CD68+/CCR7+ macrophages and no MNGCs were detected within the CG when compared to the experimental groups (P < 0.05). After 30 days, E-CHS and P-E-CHS were fully degraded. All groups showed similar inflammatory reaction shifted to a higher presence CD206+ macrophages. A low number of CCR7+ MNGCs were still observable in the implantation bed of both experimental groups. In the ex vivo model, the cells and fibrin from PRF penetrated E-CHS. However, in the case of P-E-CHS, the cells and fibrin stayed on the surface and did not penetrate towards materials central regions. The cultivation of P-E-CHS with PRF induced a statically significant higher release of pro-inflammatory proteins compared to the CG and E-CHS after 3 days.ConclusionAltering the original presentation of a hemostatic sponge biomaterial by pressing modified the initial biomaterial-cell interaction, delayed the early biomaterial’s degradation rate, and altered the vascularization pattern. A pressed biomaterial seems to induce a higher inflammatory reaction at early time points. However, altering the biomaterial did not modify the polarization pattern of macrophages compared to physiologic wound healing. The ex vivo model using PRF was shown to be an effective model to simulate the initial biomaterial-cell interaction in vivo.Clinical relevanceA pressed hemostatic sponge could be applied for guided tissue regeneration and guided bone regeneration. In that sense, within the limitations of this study, the results show that the same biomaterial may have two specific clinical indications.

Reconstitution of Highly Concentrated Lyophilized Proteins: Part 1 Amorphous Formulations

Long reconstitution times before patient administration remain an undesirable quality attribute for high concentration lyophilized protein formulations. In this study, 3 approaches were developed to study reconstitution behavior of lyophilized, amorphous cakes of a highly concentrated monoclonal antibody (mAb) by exploring their wetting, disintegration, and hydration behavior. As the mAb concentration increased from 0 to 83 mg/mL, reconstitution times were longer with poorer wetting, slower hydration, and disintegration rates. Furthermore, the effect of controlling ice nucleation temperature at −5 and −10°C during freezing followed by either conservative or aggressive drying conditions on the reconstitution times was explored in formulations containing 40 and 83 mg/mL mAb. Although no effect of either of the 2 processing conditions was noted at 40 mg/mL, aggressive drying led to faster reconstitution at both the nucleation temperatures with 83 mg/mL mAb. The present study combined with literature data suggests that below a protein-to-sugar ratio of 1, reconstitution was complete within 1 min, and when the ratio was greater than 1, the reconstitution times increased nonlinearly. Disintegration and hydration were determined to be the key mechanisms contributing to the complete reconstitution of the lyophilized, amorphous cakes of the highly concentrated mAb in vials.

Action Mechanism of Sticky Rice-Paste-Modified Site Soil: A Traditional Chinese Cementitious Material

ABSTRACTSticky rice paste is a viscous material commonly used in traditional Chinese construction. It has the basic properties of high viscosity and viscoelasticity, good corrosion and weather resistance, and a small coefficient of expansion. Sticky rice paste is usually added to site soils to modify their basic physical and mechanical properties. This study found that gelatinized sticky rice-paste-modified site soils have clearly improved physical and mechanical properties compared to 20 and 100°C water-modified soils when 1% (wt%) sticky rice paste is added as the soil modifier. The liquid and plastic limits, and the plastic index of the soil are improved upon modification, to 27.4, 17.7, and 9.7%, respectively. The unconfined compressive strength and hydraulic conductivity were significantly increased and reduced, respectively. In addition, there was a reduction in the rate of disintegration by water, while the water resistance of the soil was improved. X-ray diffraction, Fourier transform infrared, and thermogravimetry/differential scanning calorimetry studies reveal that the improved properties arise through physical processes between the sticky rice paste and the soil. Scanning electron microscopy reveals that dispersed branched-chain sticky rice-paste molecules extensively infiltrate the surfaces of the soil particles on the nanoscale and become attached to them to form a good adhesive colloid that solidifies the soil particles after water evaporation, resulting in a compact structure.

Effect of drag reducing polymers and impeller geometry on the rate of mass and heat transfer at the wall of a cylindrical stirred tank reactor in relation to catalytic reactor design

The effect of impeller geometry on the rate of liquid-solid mass transfer at the wall of the stirred tank reactor was studied by measuring the rate of the diffusion-controlled disintegration of copper in acidified dichromate. Factors examined were rotation speed of impeller and its geometry, drag reducing polymer concentration, solution physical properties and baffles effect. The mass transfer data in the blank solution were correlated by dimensionless correlations. Radial flow impellers produced higher rates of mass transfer than axial flow impellers under the same conditions. For a given set of conditions the presence of baffles was found to increase the rate of mass transfer more than unbaffled reactors. Drag reducing polymer was found to decrease the mass transfer rate by an amount ranging from 3.5 to 38.5% depending on rotation speed of impeller, polymer concentration and impeller geometry. Implication of the present results for stirred tank biochemical reactors which use drag reducing polymer to control solution viscosity and decrease the shear stress between the moving solution and the vessel wall as to protect immobilized enzyme or cells fixed to the wall against mechanical damage were discussed. The present results would help in evaluating the financial possibility of utilizing drag reducing polymers in working biochemical stirred tank reactors.

Influence on performance and emission characteristics of diesel engine by introducing medium strength magnetic field in fuel and air lines

Manufacturing In this work, the energy of electromagnet is used to treat the fuel and airline for reducing the fuel consumption and emissions in four-stroke diesel engine. The experiment comprises Internal Combustion (IC) Engine test rig and electromagnets with different intensities (4500, 6000, 8500 and 10000 gauss), are installed along the honeycomb structured mini channel fuel line and air suction line. Experiments are carried out in four-stroke diesel engine test rig for variable engine load by applying medium strength magnetic field on air and fuel supply line. The medium strength magnetic field is used to improve the atomization process effectively, due to that increment in the rate of disintegration of the droplets, as result the viscosity of the fuel decreases. Because of cohesive force between the fuel molecules are affected by the magnetic field and it leads to less surface tension force effect, thus helps to improve atomization process. It is observed that, the impact of magnetic field treatment considerably increased the brake thermal efficiency about 13% and maximum fuel reduction of 11% was obtained for field intensity 10000G and also found that the HC, CO, PM, and NOx emissions are decreased about 10.4%-14.2%, 24–25%, 13%–15%, and 8.4%-11% respectively, but CO2 is increased up to 12.2% because of association of oxygen molecules with CO which is critical point and it can be treated in the catalytic converter.

Study on Disintegration Characteristics of Improved Ancient Site Soil by Sticky Rice Solution

Some ancient sites in northwest China are exposed outdoors and damaged by rainwater erosion. To reduce the damage rate of the earthen sites, based on the principle of minimal intervention, the disintegration characteristics of compacted loess samples were improved by sticky rice solution. To analyze the effect of different concentrations of sticky rice solution on the disintegration characteristics of compacted samples, a series of disintegration experiments were carried out. The experiments results showed that the disintegration phenomenon had a significant inhibition in improved loess samples. The disintegration volume of unimproved samples was more lager than improved samples under the same time. The initial disintegration rate of improved samples was greatly reduced because of hydrophobic film formed by sticky rice solution in the surface. This paper showed that it was feasible to improve the disintegration characteristics of ancient site soil with sticky rice solution, which provided a theoretical basis for the application of sticky rice solution in the protection of earthen sites.

Impacts of different vegetation restoration options on gully head soil resistance and soil erosion in loess tablelands

AbstractVegetation restoration is identified as an effective approach to control soil erosion and affects soil detachment and resistance to concentrated flow on the Loess Plateau. However, the effects of vegetation restoration at gully heads in loess‐tableland remains unclear. This study was performed to investigate the effects of nine vegetation restoration types at gully heads on soil detachment rate (Dr) and soil resistance to concentrated flow (i.e. soil erodibility, Kr and critical shear stress, τc). Undisturbed soil samples were collected from nine vegetation‐restored lands and one slope cropland (as the control) and were subjected to a hydraulic flume to obtain Dr values of gully heads under six inflow discharges (0.5–3.5 L s‐1). The results showed that the Dr values of nine revegetated gully heads were 77.11% to 95.81% less than that of slope cropland, and the grassland dominated by Cleistogenes caespitosa and the shrubland dominated by Hippophae rhamnoides had a relatively greater decrease in Dr than those of other seven restoration types. The Dr value of nine revegetated gully heads could be better simulated by stream power than by flow velocity and shear stress and was also significantly affected by soil disintegration rate (positively), soil bulk density, saturated hydraulic conductivity, organic matter content, and water‐stable aggregate stability (negatively). Additionally, roots with diameters of 0 to 0.5 mm showed a greater effect on Dr than those with larger diameters. Compared to cropland, the nine restored types reduced Kr by 76.26% to 94.26% and improved τc by 1.51 to 4.68 times. The decrease in Kr and the increase in τc were significantly affected by organic matter content, water‐stable aggregate, mean weight diameter of aggregate and root mass density. The combination of grass species (Cleistogenes caespitosa) and shrub (Hippophae rhamnoides) could be considered the best vegetation restoration types for improving soil resistance of gully heads to concentrated flow. © 2019 John Wiley &amp; Sons, Ltd.

Estimating Deterioration Rate of Some Carbonate Rocks Used as Building Materials under Repeated Frost Damage Process, China

The degradation of natural rocks due to severe environmental conditions can influence their durability over an extended period of time. This research aims to investigate the long‐term durability or disintegration rate of rocks used as construction materials under severe climatic conditions using frost damage action, and the deterioration rate was assessed using mathematical decay function approach. The mathematical model assumes an initial order operation and gives purposeful properties for the deterioration rate of rocks due to frost action. For this reason, six different limestone types used as building materials were quarried from limestone mine in China and subjected to a series of laboratory tests to determine the mineralogical, petrographical, physical, and mechanical characteristics. Then, 50 cycles of frost damage process was performed, and after each 10 cycles, the unconfined compressive strength, point load strength, and Schmidt rebound were determined. The disintegration rate or integrity loss characteristics of each rock type were assessed using the mathematical decay function approach parameters. This approach proved that the disintegration rate varies for the rocks of the same type especially which were extracted from the same areas, the rock durability under frost damage conditions can be estimated with good accuracy, the parameters of this model saved a lot of time and provided important practical features to assess a rapid durability, and hence, there is no need to carry out the frost damage test which is slow and consumes time.

A Randomised Review on Nanotechnology and Nanosuspensions

Nanotechnology has gotten to be an fundamental component of pharmaceutical sciences and finds different applications in sedate conveyance frameworks in improving restorative execution of drugs. Numerous of the current “nano” sedate conveyance frameworks are family of customary dose shapes like nanosuspensions, nanoemulsions, and nanomicelles. Nanosuspension is an approach to convey water insoluble and ineffectively bioavailable drugs by diminishing estimate to submicron run. Subsequently its disintegration rate is expanded and thus the bioavailability, where sedate disintegration rate is the constraining calculate. nano details combine the advantage of maximizing restorative benefits with minimized side impacts and progressed security, since they have gigantic potential of being focused on at cellular level. This audit portrays different aspects of nano medicate conveyance frameworks in connection to detailing, characterization, potential benefits and dangers, and pharmaceutical applications in sedate conveyance.

Investigation on Fractal Characteristics of Disintegration Process and Strength of Rockfill under Water Pressure

The paper aimed to investigate internal mechanics between disintegration of the rockfill material and stability of the dam, and further provide scientific evidence for the design of rockfills, through the conducted disintegration of water pressure and triaxial test to analyze fractal characteristics, strength and deformation of the rockfill in whole disintegration procedure. As the results that the water pressure was low 0.2 MPa, the increasing water pressure would delay the disintegration rate of rockfill; while the water pressure was above 0.2 MPa, it would promote the disintegration rate of the rockfill. In addition, in the disintegration process, the cohesion force of rockfill rapidly slowed down at the beginning and then gradually increased. The internal friction angle increased gradually during the whole disintegration process. Furthermore, when the water pressure increased from 0 MPa to 0.6 MPa, the partial stress firstly decreased to a minimum level when the water pressure was 0.2 MPa, and then increased gradually with water pressure.

Formulation and In-Vitro Evaluation of Darifenacin Hydrobromide as Buccal Films

Darifenacin hydrobromide (DH) is the more recent uroselective M3 receptor antagonist for treating uncomplicated overactive bladder (OAB). This study was aimed to formulate DH as fast dissolving buccal films (FDBFs) using a solvent casting method to enhance patient’s compliance.&#x0D; Films were prepared by using polyvinyl alcohol (PVA) as a film forming polymer. Different types and concentrations of superdisintegrants (croscarmellose sodium, sodium starch glycolate, indion 414) were used to select the best formula by studying the physicochemical properties of the films, disintegration time (DT) and percent drug release.&#x0D; The results revealed that formula (F9) that containing 7.5mg DH, 2%w/v PVA, 30%w/w glycerol, 0.5%w/v tween 80, 4%w/w indion 414 was the preferred formula. F9 showed the shortest in-vitro disintegration time (31.28sec). In-vitro dissolution profile showed the lowest T80% of the drug in 3.05 min and the highest release of the drug (94%) within 5 min (D5min %).&#x0D; It was concluded that the FDBFs of DH could be considered as a promising drug delivery system with an enhanced disintegration and dissolution rate and better patient compliance.

Using multi-fractal analysis to characterize the variability of soil physical properties in subsided land in coal-mined area

Underground coal-mining activities can result in severe land subsidence; the soils are severely damaged and the hydrological process is disturbed. Understanding the spatial variability of soil physical properties is helpful to analyze the effects of underground mining on these properties and select suitable land rehabilitation measures. In the present study, multi-fractal analysis was used to reveal the effects of land subsidence and rehabilitation on the spatial variability of soil physical properties. Three plots from Pingshuo coal mine area in Shanxi Province of China, including one unmined plot (UMP), one subsided plots (SUP), and one rehabilitated plot (RHP), were selected for the study. Sixteen sampling points were identified in each plot. Four typical soil physical properties, namely bulk density (BD), field capacity (FC), saturated hydraulic conductivity (Ks), and soil disintegration rate (SDR) at depths of 0–20, 20–40, 40–60 and 60–80 cm at each sampling point were measured. Generalized dimensions and singularity spectra of the distributions of different soil physical properties were calculated for each plot. Parameters D1 and ΔD of the generalized dimensions, and Δα and Δf of singularity spectra, were extracted. Multi-fractal analysis is highly sensitive to the spatial variability of soil physical properties and provides valuable information for depicting spatial variability of these properties, including the concentration degree, dispersion degree, local variability degree, overall non-uniformity, and symmetry degree of spatial distribution. Land subsidence increased the spatial variability of soil physical properties, especially in terms of Ks and SDR, whereas land rehabilitation had the opposite effect. Compared to the UMP, the degree of local variability of Ks and SDR distributions increased by 191% and 132% in the SUP, respectively, whereas these factors decreased by 41% and 51% after land rehabilitation, respectively. The spatial variability of soil physical properties in the SUP was the highest compared to UMP and RHP. It is feasible to utilize multi-fractal techniques to assess the spatial variability of soil physical properties at the scale of a subsided plot in a coal-mined area. Information on the variability of soil physical properties at a small scale is required to more accurately restore soil environment and soil function through rehabilitation.

Changes in soil properties and resistance to concentrated flow across a 25‐year passive restoration chronosequence of grasslands on the Chinese Loess Plateau

Revegetation represents an effective measure for preventing soil erosion on the Loess Plateau. However, the effects of revegetation‐induced changes in soil and root properties on soil resistance to concentrated flow erosion (SRC) remain unclear. This study sampled soils and roots across a 25‐year chronosequence from farmland to grasslands of different ages (3, 7, 10, 18, and 25 years) to quantify variations in soil and root properties (soil bulk density, SBD; soil disintegration rate, SDR; saturated hydraulic conductivity, SHC; organic matter content, OMC; water‐stable aggregate, WSA; mean weight diameter, MWD; root mass density, RMD; root length density, RLD; and root surface area density, RSAD) and their effects on SRC. Farmland and grassland SRCs were obtained using a hydraulic flume. Soil properties and root density gradually improved with restoration time. In terms of the comprehensive soil property index calculated via principal component analysis, grassland values were 0.66 to 1.94 times greater than farmland values. Grassland SRCs increased and gradually stabilized (&gt;18 years) over time and were 1.60 to 8.26 times greater than farmland SRC. SRC improvement was significantly related to increases in OMC, SHC, WSA, and MWD and decreases in SBD and SDR over time. SRC was effectively simulated by the Hill curve of RMD, RLD, and RSAD. SDR, SHC, and RMD (0.5–1.0 mm) affected SRC the most. This study scientifically describes how revegetation improves soil quality and soil resistance to flow erosion, and suggests that vegetations rich in 0.5–1.0 mm roots should be preferred during revegetation.

Synthesis of Bombax malabaricum gum based silver and zinc nanoparticles and their application in controlled drug delivery

Herein, simple and eco-friendly biosynthesis of silver and zinc nanoparticles using crude and modified (carboxymethylated) Bombax malabaricum gum has been used to evaluate as a bio-binder for drug formulation. The synthesized nanoparticles were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and thermogravimetric analyzer (TGA). SEM revealed that the surface of crude gum sample was relatively homogeneous and smooth whereas, some cracks appeared on the surface after the modification and gum-based nanoparticles. X-ray pattern of modified and nanoparticles samples of gum indicates the crystalline structure of modified gum and nanoparticles. TGA determined that weight loss of modified gum and nanoparticles did not occur rapidly as compared to the crude gum. The toxicological potential evaluated through hemolytic test revealed good blood compatibility and non-hemolytic nature of gum samples. Finally, B. malabaricum plant gum ability as a binder in drug delivery was investigated through hardness, dissolution and disintegration rate. All the prepared tablets showed hardness of more than 4 kg, whereas the disintegration and dissolution time for all gum samples was less than 15 and 30 min, respectively. Tablets prepared from crude and purified gum samples showed slow disintegration and dissolution release of drug as compared to the tablets prepared using modified gum and their nanoparticles. Taken together, the findings suggest that B. malabaricum gum is non-toxic and non-mutagenic and can be used as a bio-binder in the drug formulation. Natural plant gums-based nanoparticles have great potential to be used in pharmaceutical industries against artificially synthesized drugs for controlled drug delivery applications.