HCl pH Research Articles

A flexible and transparent superhydrophobic coating on cotton fabrics with high mechanical and chemical stability for underwater insulation

Achieving both stretchability and excellent transparency of superhydrophobic surfaces simultaneously is a major challenge. We utilize three acrylic monomers 1H,1H,2H,2H-heptadecafluorodecyl acrylate, methyl methacrylate, 3-(trimethoxysilyl) propyl methacrylate to polymerize flexible, transparent, low surface energy random copolymers (PHMK) as the coating. The coating has excellent transparency (90.2 %) and the coated elastic cotton fabric exhibits superhydrophobicity (WCA = 160°) even at the tensile strain of 0–300 %. The water droplets on the surface can bounce repeatedly in a stretched state. The coating has excellent chemical and mechanical stability and maintains superhydrophobicity under various treatments such as in various organic solvents and HCl (pH = 1) immersion, 20 washing cycles, the Martindale abrasion test 1000 times, and the tape peeling test 600 times. In addition, the coated cotton fabric also has excellent underwater thermal insulation performance, which has great potential application in fields such as life jackets.

A novel method of rapid detection for heavy metal copper ion via a specific copper chelator bathocuproinedisulfonic acid disodium salt

The extensive usage and production of copper may lead to toxic effects in organisms due to its accumulation in the environment. Traditional methods for copper detection are time consuming and infeasible for field usage. It is necessary to discover a real-time, rapid and economical method for detecting copper to ensure human health and environmental safety. Here we developed a colorimetric paper strip method and optimized spectrum method for rapid detection of copper ion based on the specific copper chelator bathocuproinedisulfonic acid disodium salt (BCS). Both biological assays and chemical methods verified the specificity of BCS for copper. The optimized reaction conditions were 50 mM Tris–HCl pH 7.4, 200 µM BCS, 1 mM ascorbate and less than 50 µM copper. The detection limit of the copper paper strip test was 0.5 mg/L by direct visual observation and the detection time was less than 1 min. The detection results of grape, peach, apple, spinach and cabbage by the optimized spectrum method were 0.91 μg/g, 0.87 μg/g, 0.19 μg/g, 1.37 μg/g and 0.39 μg/g, respectively. The paper strip assays showed that the copper contents of grape, peach, apple, spinach and cabbage were 0.8 mg/L, 0.9 mg/L, 0.2 mg/L, 1.3 mg/L and 0.5 mg/L, respectively. These results correlated well with those determined by inductively coupled plasma-mass spectrometry (ICP-MS). The visual detection limit of the paper strip based on Cu-BCS-AgNPs was 0.06 mg/L. Our study demonstrates the potential for on-site, rapid and cost-effective copper monitoring of foods and the environment.

Florfenicol sustained-release granules: an in vitro-in vivo correlation study in pigs

The objective of this study was to synthesize and characterize pharmaceutical characteristics of florfenicol sustained-release granules (FSRGs) in vitro and in vivo. FSRGs were synthesized using monostearate, polyethylene glycol 4000 and starch. In vitro dissolution profiles were studied using the rotating basket method in pH 1.2 HCl solution and pH 4.3 acetate buffer. Twenty-four male healthy Landrace×Yorkshire pigs were equally divided into three groups and administered a 20 mg/kg i.v bolus of florfenicol solution and dosed orally with FSRGs in the fasting and fed states. The Higuchi model was the best fit for the drug release profile in pH 1.2 and pH 4.3 media, and the mechanism of drug dissolution was governed by both diffusion and dissolution. We established a level A in vitro - in vivo correlation for FSRGs and the in vivo profile of the FSRGs can be estimated by the in vitro drug release.

Research on the distribution of S species in the pressure oxidation leaching process of SrS solution

Strontium compounds apply extensively in a variety of domains. Commonly, strontium compounds are made by carbonization of SrS solution. H2S is readily generated in this process. To avoid H2S byproducing, a novel strategy for the pressure oxidation leaching process of SrS solution was used. The overoxidation of sulfides was restrained, and a higher separation efficiency of Sr and S was obtained, which was beneficial for synthesizing other strontium compounds. The effects of the oxidation pH environment, reaction temperature, initial total sulfide concentration and reaction time on the conversion ratio of S species were investigated. The results showed that S0 was preferably generated in a near-neutral, low-temperature and low initial total sulfide concentration oxidation environment. The optimum oxidation conditions were summarized experimentally: 48 mL/L HCl (pH = 7.11), 25 °C reaction temperature, 8.2 g/L initial total sulfide concentration and 60 min reaction time. The optimum conversion ratios were obtained under optimum oxidation conditions as follows: χsulfide 2.3%, χH2S 0.5%, χS0 81.5%, χinter 10.0% and χS - Sr 5.7%. SrCl2 crystal was recovered finally from the leachate. At last, the pressure oxidation mechanism of SrS was discussed.

Exploring magnetic capture to improve the detection of human norovirus in strawberries

AbstractHuman norovirus is a leading cause of foodborne illness worldwide, and its detection in foods remains a challenge due to the difficulty of eluting and enriching trace amounts of viral particles. In this study, we developed porcine gastric mucin–labeled magnetic capture probes and optimized the conditions for their binding with norovirus, elution of viral particles, and RNA isolation based on the previous research. We evaluated the magnetic capture‐based pretreatment method in artificially contaminated strawberry samples and compared it with the conventional polyethylene glycol precipitation–based method using reverse transcriptional‐quantitative PCR (RT‐qPCR). The results revealed that Tris·HCl (pH 9.5) was the optimal buffer for the binding of magnetic probes with viral particles, and RNA recovery rate obtained by heating‐based release was significantly higher than that obtained by a commercial kit, with only active virus being captured. This buffer was similar to the RT‐qPCR buffer, which facilitated the sensitivity of RT‐qPCR. Furthermore, the buffer was an effective solution for eluting viral particles from foods in previous research and was optimized to ensure maximum elution and no inhibitory effect on viral capture. We explored multiple factors or steps to ensure that the sensitivity of our method was three orders of magnitude higher than that of the conventional method. Our findings suggest that magnetic capture‐based detection has great potential for the sensitive detection of human norovirus.

Formulation and Evaluation as Sustain Released Nanoparticles for Zolmitriptan Hydrochloride for the enhanced Bioavailability and Better Therapeutic Action by using Chitosan as a Permeation Enhancer

Chitosan was hydrophobically modified as N-Butyryl chitosan (NBC), N-Lauroyl chitosan (NLC) were synthesized and characterized by FTIR, NMR, XRD, modified chitosan were having about 14 % degree of substitution and varying solubility. Further evaluation of synthesized N-acyl chitosan to loaded Zolmitriptan HCl as nanoparticle by ionotropic method with cross linking by TPP. Average particle size, drug loading, entrapment efficiency and in-vitro mucoadhesion of Zolmitriptan HCl loaded nanoparticle was 150.7±3.3nm, 24.80±1.1% and 54.96±3.8% respectively, with positive zeta potential which were directly correlated with increases bulkiness of the acyl substitution in the modified chitosan except zeta potential was found inversely correlated. TEM and SEM imaging relieved spherical structure of nanoparticle. In vitro release of Zolmitriptan HCl in 1.2 pH HCl buffer and pH 7.4 phosphate buffer solutions showed biphasic release pattern best fitted with Korsmeyer’s-Peppas kinetics with fickian transport mechanism. Acylated chitosan showed sustained release reducing with increasing length of acyl group. Result of the present study showed that hydrophobically modified acylated chitosan can be useful for achieving sustained release controlled by acylation modification.

Chitosan/PVA Nanofibers as Potential Material for the Development of Soft Actuators.

Chitosan/PVA nanofibrous electroresponsive soft actuators were successfully obtained using an electrospinning process, which showed fast speed displacement under an acidic environment. Chitosan/PVA nanofibers were prepared and characterized, and their electroactive response was tested. Chitosan/PVA nanofibers were electrospun from a chitosan/PVA solution at different chitosan contents (2.5, 3, 3.5, and 4 wt.%). Nanofibers samples were characterized using Fourier transform infrared analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), optical microscopy, and tensile test. The electroactive behavior of the nanofiber hydrogels was tested under different HCl pH (2-6) under a constant voltage (10 V). The electroactive response test showed a dependence between the nanofiber's chitosan content and pH with the bending speed displacement, reaching a maximum speed displacement of 1.86 mm-1 in a pH 3 sample with a chitosan content of 4 wt.%. The results of the electroactive response were further supported by the determination of the proportion of free amine groups, though deconvoluting the FTIR spectra in the range of 3000-3700 cm-1. Deconvolution results showed that the proportion of free amine increased as the chitosan content was higher, being 3.6% and 4.59% for nanofibers with chitosan content of 2.5 and 4 wt.%, respectively.

Influence of pH on the release of a once daily formulation of ciprofloxacin tablets prepared with different polymers

Purpose: To study the release behaviour of ciprofloxacin hydrochloride tablet matrices prepared with different polymers in dissolution media of different pH. Methods: Different formulations of slow-release matrix tablets of ciprofloxacin hydrochloride were prepared with polymers, namely, ethyl cellulose (Etc), hydroxyethyl cellulose (Hec), hydroxypropyl methylcellulose (Hpc), and Eudragit® L-100 (Eud) using matrix embedding technique. The matrix tablets were characterized and studies of their dissolution profiles were studied in 0.1 N HCl (pH 1.2) and in simulated intestinal fluid (excluding enzymes) of pH 4.0, 6.0, and 7.4. Results: The tablets had the following characteristics: weight, 659.25 ± 7.96 to 661.65 ± 6.53 mg; hardness, 7.05 ± 0.21 to 9.60 ± 0.40 kgf; friability, 0.212 to 0.292 %; and drug content, 91.47 ± 0.53 to 112.50 ± 4.14 %. In batches prepared with ethyl cellulose, Eudragit L-100, and hydroxypropyl methylcellulose, drug release increased with a decrease in pH. However, matrix tablets prepared with hydroxyethyl cellulose displayed the highest drug release at pH 4.0 with Cmax of 108.75 % and T50% of 30.86 min; thereafter, drug release decreased with increase in pH. The pattern of drug release was Hec > Hpc > Eud > Etc in most media with more drug release in acidic than at alkaline pH. Conclusion: Release of ciprofloxacin from the formulated matrix tablets was pH-sensitive in vitro. This should be taken into consideration in designing sustained release oral form of ciprofloxacin.

Multifunctional coating on magnesium alloy: Superhydrophobic, self-healing, anti-corrosion and wear-resistant

Superhydrophobic coating (SHC) was fabricated on magnesium (Mg) alloy by sequential surface etching, in-situ growth of MgAl-layered double hydroxides (LDHs), and modification of octadecyl-trimethoxy-silane (OTMS). The so-fabricated SHC possessed high contact angle above 150° and low sliding angle below 10° by using the probe droplet of aqueous solution of HCl (pH = 2), NaOH (pH = 13), NaCl (3.5 wt.%) or others such as milk, cola, and tea. The lubricant behavior as well as wear resistance was enhanced by such a SHC as compared with the bare Mg alloy. Moreover, corrosion of Mg alloy was greatly slowed by such a SHC which maintained long-term hydrophobic property after corrosion immersion in aqueous solution of NaCl for 6 weeks. The scratch on the SHC could be self-healed by immersing into water due to the hydrolytic polycondensation of silane and corrosion decomposition of LDHs within 8 days.

Macro-meso deterioration characteristics and statistical damage constitutive model for acid-corroded sandstone

Long-term hydrochemical corrosion leads to mineral dissolution, meso-structure change, and further mechanical deterioration of rock. This paper studied the effects of pH = 1, 3, 5 HCl solutions and pH = 7H2O on sandstone damage from macro-meso perspectives. The mesostructure from different corroded parts was fine analyzed, and the sandstone porosity was calculated by CT (Computed Tomography) image processing techniques. The mechanical properties and energy evolution laws under uniaxial compression were investigated. The full deformation of sandstone was theoretically analyzed, and the damage constitutive model considering initial compression was developed and verified. The results showed that after acid corrosion, more pores and microcracks occurred in the sandstone, the mesostructure became loose, and the calculated porosity based on CT images can represent the actual sandstone porosity. The yield stress, peak stress, and elastic modulus declined, and the peak strain improved. The energy storage capacity weakened, and the plastic deformation before the peak point increased. The effects were more evident with the acidity and immersion time. The acid-corroded sandstone was abstracted into two portions: the initial voids and the solid skeleton. The initial voids deformed nonlinearly in the compaction stage, and the solid skeleton deformed linearly before yielding and nonlinearly after yielding. The theoretical curves of the constitutive model for acid-corroded sandstone agreed well with the experimental ones, which verifies the model is reasonable.

Antimonene-Modified Screen-Printed Carbon Nanofibers Electrode for Enhanced Electroanalytical Response of Metal Ions

A two-dimensional (2D) Sb-modified screen-printed carbon nanofibers electrode (2D Sbexf-SPCNFE) was developed to improve the stripping voltammetric determination of Cd(II) and Pb(II), taking advantage of the synergistic effect between the two nanomaterials. The surface morphology of the 2D Sbexf-SPCNFE was investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Raman spectroscopy. The analytical performance of 2D Sbexf-SPCNFE was compared to those presented by screen-printed carbon electrodes modified with 2D Sbexf (2D Sbexf-SPCE) and the corresponding bare electrodes: screen-printed carbon nanofibers electrode (SPCNFEbare) and screen-printed carbon electrode (SPCEbare). After optimizing the experimental conditions, the 2D Sbexf-SPCNFE exhibited much better analytical parameters compared to the other assessed sensors. Analysis in 0.01 mol L−1 HCl (pH = 2) using 2D Sbexf-SPCNFE showed excellent linear behavior in the concentration range of 2.9 to 85.0 µg L−1 and 0.3 to 82.0 µg L−1 for Cd(II) and Pb(II), respectively. The limits of detection after 240 s deposition time for Cd(II) and Pb(II) were 0.9 and 0.1 µg L−1, and sensitivities between 1.5 and 3 times higher than those displayed by SPCEbare, SPCNFEbare, and 2D Sbexf-SPCE were obtained. Finally, the 2D Sbexf-SPCNFE was successfully applied to the determination of Cd(II) and Pb(II) traces in a certified estuarine water sample.

Aqueous formate solution for enhanced water imbibition in oil recovery and carbon storage in carbonate reservoirs

This paper presents an experimental study of the injection of aqueous formate solution into oil-wet carbonate porous media at different formate concentrations and acidity levels. The research was motivated by the potential use of aqueous formate solution as a wettability modifier in enhanced oil recovery and/or a carbon carrier in geological carbon storage in carbonate reservoirs. However, the wettability alteration of carbonate rocks by formate has not been tested at elevated concentrations of formate or in any coreflood. The experimental program in this research consists of aqueous stability, wettability alteration, and three dynamic imbibition experiments with fractured carbonate cores with varying formate concentrations up to 30 wt% and initial pH between 6 and 7.With an excess amount of calcite powder, the 20 wt% formate solution in 15000 ppm NaCl brine showed essentially the same pH history as the base NaCl brine, where calcite dissolution caused the solution pH to increase to a stable value near 9. None of the samples studied in this research showed solid precipitation. Material balance of dynamic imbibition data indicated that the imbibition of formate into the matrix was most significant in coreflood #1, in which 30 wt% formate solution was injected into a fractured carbonate core. A large gradient in formate concentration between the fracture and the matrix likely caused the rapid mass transfer. Then, calcite dissolution and the resulting formate species caused wettability alteration to enhance water imbibition, which in turn expelled the oil in the matrix.The incremental oil recovery factor was 9.1 % for 30 wt% formate (pH = 7; coreflood #1), 2.9 % for 5 wt% formate (pH = 7; coreflood #2), and 7.0 % for 5 wt% formate + HCl (pH = 6; coreflood #3). A greater oil recovery factor resulted from a greater concentration of formate and a reduced pH. This is the first time corefloods were performed with aqueous formate solution at elevated concentrations up to 30 wt%.

Nanobacterial Cellulose from Kombucha Fermentation as a Potential Protective Carrier of Lactobacillus plantarum under Simulated Gastrointestinal Tract Conditions.

Kombucha bacterial cellulose (KBC), a by-product of kombucha fermentation, can be used as a biomaterial for microbial immobilization. In this study, we investigated the properties of KBC produced from green tea kombucha fermentation on days 7, 14, and 30 and its potential as a protective carrier of Lactobacillus plantarum, a representative beneficial bacteria. The highest KBC yield (6.5%) was obtained on day 30. Scanning electron microscopy showed the development and changes in the fibrous structure of the KBC over time. They had crystallinity indices of 90-95%, crystallite sizes of 5.36-5.98 nm, and are identified as type I cellulose according to X-ray diffraction analysis. The 30-day KBC had the highest surface area of 19.91 m2/g, which was measured using the Brunauer-Emmett-Teller method. This was used to immobilize L. plantarum TISTR 541 cells using the adsorption-incubation method, by which 16.20 log CFU/g of immobilized cells was achieved. The amount of immobilized L. plantarum decreased to 7.98 log CFU/g after freeze-drying and to 2.94 log CFU/g after being exposed to simulated gastrointestinal tract conditions (HCl pH 2.0 and 0.3% bile salt), whereas the non-immobilized culture was not detected. This indicated its potential as a protective carrier to deliver beneficial bacteria to the gastrointestinal tract.

A COMPARATIVE EVALUATION OF EFFICACY OF TETRACYCLINE HCL, EDTA & HYALURONIC ACID GEL AS ROOT BIOMODIFICATION AGENTS. -AN IN-VITRO SEM STUDY

Background: Scaling and Root Planing alone leaves a smear layer on the root surface which may interfere with reattachment of cells to root surface during regenerative periodontal therapy. Root bio-modification has been advocated for smear layer removal which may enhance regeneration. Objective: To evaluate and compare effect of 17% Ethylenediamine Tetra Acetic acid (EDTA), Tetracycline HCL and 1% Hyaluronic Acid gel as root conditioning agents on periodontally involved root surfaces of extracted teeth using a scanning electron microscope (SEM). Materials And Method: Freshly extracted 10 single rooted human teeth were sectioned into 30 samples and were segregated into 3 groups: 1. Group â… - tetracycline HCl (pH 1.6), 2. Group â…¡ – EDTA 17% (pH 7.3), 3. Group III – HA gel 2%. The samples were treated with respective agents and were viewed under 4000X magnification using a SEM. The specimens were assessed for the Residual smear layer score, Number of patent tubules, Total number of dentinal tubules, Proportion of patent to total number of dentinal tubules and Mean Diameter of dentinal tubules. Results: Group I and Group II were significantly better than Group III for all the measured parameters. However, the number of patent dentinal tubules, total number of dentinal tubules and mean diameter of dentinal tubules were significantly superior in Group II as compared to Group I. Conclusion: Tetracycline HCL was found to be the most effective root conditioning agent amongst the 3 groups, for the assessed parameters.

Effect of artificial aging on optical properties and crystalline structure of high-translucency zirconia.

To investigate the effect of different in vitro aging protocols on the optical properties and crystalline structure of high-translucency (HT) zirconia. Thirty-six specimens of HT and extra-high translucency (XT) zirconia were divided into three groups: control (CO)-no treatment; hydrothermal aging (HA)-autoclave aging for 12.5h at 134°C, 2bar; clinically related aging (CRA)-aging in the chewing simulator for 1.2 million cycles, followed by 50,000 thermocycles (5-55°C) and immersion in HCl (pH 1.2) for 15h. Optical properties, crystalline structure, and surface roughness were analyzed and compared using analysis of variance (5% significance level). There was no statistically significant effect of aging on translucency (p=0.10), but CRA promoted the development of a high contrast ratio (p=0.03). Aging did not cause significant color changes for HT (p=0.65) or XT (p=0.36). The proportion of monoclinic crystals increased to 40% for HT-zirconia after HA and 5% after CRA. No monoclinic crystals were detected for XT groups. There was no effect of aging on surface roughness (p=0.77). Although hydrothermal aging has been widely used to verify zirconia crystalline stability, it did not generate an effect similar to clinically related aging on the optical properties and crystalline structure of zirconia. HA affected the crystalline structure of HT-zirconia, and CRA compromised the optical properties of XT zirconia.

Development of UV-Visible spectrophotometric method for the estimation of vildagliptin in different medium

A simple, accurate, precise, cost effective, rapid and sensitive UV/visible spectrophotometric method was developed for the determination of Vildagliptin in active pharmaceutical dosage form. The developed method was validated as per ICH guidelines.The purity of Vildagliptin was characterized by melting point, Fourier Transform Infra-Red and DSC. The drug was analyzed using UV/visible spectrophotometric method was validated in terms of linearity and range. The solvents used was water, 0.1 N HCl and phosphate buffer pH 7.4 and the wavelength corresponding to maximum absorbance of the drug were found at 210 nm.Melting point of drug was found 151.67°C nearly corresponds to its actual melting range. The linear response for concentration range of 2-12 µg/ml of vildagliptin for water, 0.1 N HCl and phosphate buffer pH 7.4 was recorded each with regression coefficient R = 0.9998, 0.9994 and 0.9991 respectively.The drug was confirmed by interpretation of UV spectra. Hence, proposed method stands out validated and shows a linear relationship and thus may be used for routine analysis of Vildagliptin in pharmaceutical dosage forms.

Solutions Containing a Statherin-Derived Peptide Reduce Enamel Erosion in vitro

The effect of solutions containing a statherin-derived peptide (Stn15pSpS) on the protection against enamel erosion in vitro was evaluated. Bovine enamel specimens were divided into 4 groups (n = 15/group): (1) deionized water (negative control), (2) Elmex Erosion Protection™ (positive control), (3) 1.88 × 10⁻⁵ M Stn15pSpS, and (4) 3.76 × 10⁻⁵ M Stn15pSpS. The solutions were applied on the specimens for 1 min. Stimulated saliva was collected from 3 donors and used to form a 2-h acquired pellicle on the specimens. Then, the specimens were submitted to an erosive pH-cycling protocol 4 times/day, for 7 days (0.01 M HCl pH 2.0/45 s, artificial saliva/2 h, and artificial saliva overnight). The solutions were applied again during pH-cycling, 2 times/day for 1 min after the first and last erosive challenges. Enamel loss (μm) was assessed by contact profilometry. Data were analyzed by Kruskal-Wallis and Dunn’s test (p < 0.05). The best protection against erosion was conferred by Elmex Erosion Protection that significantly differed from all the other treatments, followed by the solutions containing Stn15pSpS, regardless of the concentration. However, 3.76 × 10⁻⁵ M Stn15pSpS did not differ from the negative control. The solution containing the lower concentration of Stn15pSpS protected against erosion in vitro, which should be confirmed using protocols that more closely resemble the clinical condition.

Pre-Incubation of Probiotics Before Intake: A Reasonable Recommendation?

Abstract Background Protecting the bacteria contained in probiotics against the effects of low pH is one of the key issues for the development and production of such products. In earlier research we demonstrated that the inactivation of bacteria in probiotics by low pH can be prevented by an effective enteric coating formulation of the product. Objective The present study aimed to evaluate whether the producer’s recommended pre-incubation step for its probiotic product A prior to intake is having an effect on the survival rate of the product’s bacteria in low pH solutions. Method For the investigated product A (and an enteric coated reference product B) amounts of colony forming units (CFU) before and after pre-incubations for 0, 1 and 30 min followed by exposure to 0.1 N HCl (pH 1.2) at 37°C for 90 min were determined. The loss of living bacteria was calculated using the CFU1/CFU0-ratio, with CFU1 and CFU0 being the amount of CFU at the end and at the beginning of the experiment, respectively. Results The exposure of the product A to a low pH (1.2) resulted in a strong reduction of the amount of CFU (about -99.9%). Pre-incubation of product A neither for one nor for 30 min had a significant effect on the strong loss of viability of the probiotic bacteria contained in product A when compared to the loss without the pre-incubation process. In contrast, exposing the enteric coated product B to low pH resulted only in a minor loss (about -7%) of living bacteria. Conclusions The pre-incubation before intake recommended by the producer of product A is not having a significant influence on a major reduction of CFU caused by the exposure to low pH. However, the observed considerable loss of CFU in a solution that mimics the condition in the human stomach triggers doubts about product A. We strongly suggest basing probiotic product related statements on scientific data.

Superporous acrylic acid and HPMC hydrogels of mefenamic acid: Formulation, characterization and optimization by central composite design.

The purpose of the study was to devise the superporous hydrogels (SPHs) of mefenamic acid (MA) to acquire the sustained action of the MA in the body. The superporous hydrogels of mefenamic acid were formulated by employing the gas blowing method. The central composite rotatable design (CCRD) was applied to optimize the effect of independent formulation factors like acrylic acid (AC), HPMC and glycerol (GLY) over dependent variables like porosity, viscosity, drug content and swelling ratio of superporous hydrogels in water, phosphate buffer (pH 6.8) and in 0.1N HCl (pH 1.2). A number of characteristics such as void fraction, surface morphology by Scanning electron microscopy (SEM) and in vitro drug release study were governed along with physico-chemical analysis by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and appraised statistically by employing the ANOVA. The comparative analgesic activity of optimized superporous hydrogel formulation SPH17 was also analyzed by using tail flick method. The Fourier transform infrared spectroscopy and Differential scanning calorimetry studies approved the physical compatibility between the polymers and the drug. The Scanning electron microscopy study specified micrographic insight about the structure of formed formulations comprising presence of pores, fibers and drug-hole aggregates. The superporous hydrogels were detected to be low dense as they expressed density lower than 0.75g/cc. The decrease in concentration of the polymers and cross linker contributed towards the increase in the void fraction of the superporous hydrogel formulations. The optimized formulation SPH 17 exhibited a highly sustained release of MA for up to 10h in the both 0.1N HCl and phosphate buffer (66.6%) media. The non-fickian release of drug revealed the coupling of the diffusion and polymer relaxation mechanism of the drug release from the formulations. The obtained outcomes suggested that analgesic effect of SPH 17 was significantly (p < 0.05) higher than that of simple suspension of mefenamic acid and total analgesic effect duration for superporous hydrogel was also doubled as compared to the duration of analgesic effect produced by drug suspension. The successfully formulated SPH with HPMC K100M as a gelling agent had sustained the action of the mefenamic acid (MF) by improving its poor solubility and permeability. The introduction of inter-penetrating polymeric network (acrylic acid) using glycerol as a cross linker impart increased residence time to superporous hydrogels which ultimately enhanced the feasibility of using superporous hydrogel as oral sustained release devices particularly for gastric retention.

Sorafenib tosylate loaded superparamagnetic nanoparticles: Development, optimization and cytotoxicity analysis on HepG2 human hepatocellular carcinoma cell line

Iron oxide (magnetite) is the core of magnetic nanoparticles, which can be directed to the desired location using an external magnet. In this study, the magnetic nanoparticles were prepared by an emulsion solvent evaporation method and optimized using Box Behnken design. The mean particle size, polydispersity index, and zeta potential of optimized nanoparticles (formulation PMP-11) were 71.81 ± 4.4 to 384.1 ± 10.5 nm, 0.203 ± 0.008 to 0.777 ± 0.010, and −34.4 ± 3.1 to −10.2 ± 0.6 mV, respectively. The entrapment efficiency was found to be 84.64 ± 0.78%. TEM image confirmed formation of spherical nanoparticles. After 24 h, the formulations released 25.18%–56.63% and 54.38%–90.56% of loaded drug in phosphate buffer (6.8 pH) and 0.1 N HCl (pH 1.2), respectively. In HepG2 cell lines, the IC50 value of optimized formulation was recorded to be 38.12 μg/mL. XRD analysis confirmed amorphous form of loaded drug. The mean average surface roughness for magnetite and optimized formulation was found to be 5.27025 nm and 8.29138 nm, respectively. The magnetization saturation for magnetite and optimized was 28.58 emu/g and 25.46 emu/g, respectively. Electron paramagnetic resonance spectroscopy of pure magnetite indicated g-Lande factor of 4.30 (typical for Fe3+ ions). The g factor for optimized formulation was 4.24 suggesting superparamagnetic nature of the particles.