Fourier Transform Infrared Spectroscopy Studies Research Articles

Extraction, Characterization, and Antimicrobial Activity of Chitosan from Horse Mussel Modiolus modiolus.

Chitin and chitosan have been proved to have enormous applications in biomedical, pharmaceutical, and industrial fields. The horse mussel, Modiolus modiolus, a refuse of the fishery industries at Thondi, is a reserve of rich chitin. The aim of this work is to extract chitosan from the horse mussel and its further characterization using Fourier transform infrared spectroscopy (FTIR), micro-Raman spectroscopy, X-ray diffraction (XRD), and elemental analysis. The result of FTIR studies revealed different functional groups of organic compounds such as out-of-plane bending (564 cm–1), C–O–C stretching (711 cm–1), and CH2 stretching (1174 cm–1) in chitosan. The degree of acetylation of the extracted chitosan was observed to be 57.43%, which makes it suitable as a biopolymer for biomedical applications. Prominent peaks observed with micro-Raman studies were at 484 cm–1 (14,264 counts/s), 2138 cm–1 (45,061 counts/s), and 2447 cm–1 (45,636 counts/s). XRD studies showed the crystalline nature of the polymer, and the maximum peak was observed at 20.04°. Elemental analysis showed a considerable decrease in the percentage of nitrogen and carbon upon the conversion of chitin to chitosan, while chitosan had a higher percentage of hydrogen and sulfur. The antibacterial activities of chitosan from the horse mussel were found to be efficient at a 200 μg/mL concentration against all the bacterial strains tested with a comparatively higher antibacterial activity against Escherichia coli (9 mm) and Bacillus subtilis (8 mm).

Poly(diallyldimethylammonium chloride)-grafted carboxylated-MWCNT as an additive in the polyethersulfone membrane

Surface modification of carbon nanotubes is a common method to improve their compatibility with polymer matrix in membranes. In this study, polyethersulfone (PES) nanocomposite membranes were prepared by incorporation of modified multi-walled carbon nanotubes (MWCNT). For this purpose, diallyldimethylammonium chloride was used as a monomer for the functionalization of carboxylated-MWCNT via in situ polymerization. Synthesized polymer possessed a positive charge on repeating unit, which increased the hydrophilicity of carboxylated-MWCNT. The properties and performances of the modified carboxylated-MWCNT and nanocomposite membranes were investigated by field emission scanning electron microscopy, thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FT-IR), contact angle measurement, salt, heavy metal, and dye removal, and fouling studies. The occurrence of the modification reaction was confirmed by FT-IR and TGA studies. Results showed that the incorporation of modified carboxylated-MWCNT into polyethersulfone membranes improved their performance in the separation of salts, heavy metal ions, and dyes. Furthermore, the surface hydrophilicity of membranes was improved by loading of modified carboxylated-MWCNT, and other properties like the pure water flux and anti-fouling resistance of PES membranes were refined remarkably. More importantly, the membranes containing modified additive showed pH sensitivity because of ammonium groups in the attached polymer chain.

Formulation of non-effervescent floating matrix tablets of metronidazole using <I>Abelmoschus esculentus</I> gum as binder and 2-camphanone as sublimating agent.

The aim of this study was to formulate non-effervescent floating drug delivery system of metronidazole tablets using Abelmoschus esculentus (Okra) (AE) gum as a binder and 2-camphanone (camphor®) as the sublimating agent. Granules were prepared by wet granulation technique using varying concentrations of AE gum (2, 4, 6 and 8% w/w) admixed with 1%w/w acrylate methacrylate copolymer. A 30 %w/w of 2-camphanone was used as the sublimating agent. The granules were characterized for micromeritic properties. And thereafter, compressed at a compression pressure of 25 N/m2 using a Manesty single punch tableting machine. The metronidazole tablet was then sintered at 70oC for 12 h. Drug-excipient compatibility study was done using Fourier Transform Infra-red Spectroscopy (FTIR). Tablets were evaluated for floating lag time, in-vitro buoyancy and release kinetics. FTIR studies showed that the excipients and the active pharmaceutical ingredient (API) i.e. metronidazole, were compatible. All the granules were free flowing, with Carr’s index ≤ 15 %, Hausner ratio ≤ 1.18 and angle of repose of ≤ 33.5o. The tablets had hardness and friability values of 5.0-9.5 N and 0.4-0.8% respectively. The floating lag time was 0 s showing that the tablets floated immediately after immersion in the simulated gastric fluid. The maximum % release (m∞) and time to achieve it (t∞) were ≥ 88 % and ≥ 10 h, respectively. Release exponent (n) for all the formulations had values >0.45, hence their release was by non-Fickian diffusion. Non-effervescent floating matrix tablets of metronidazole were formulated using AE gum as the binder and 2-camphanone as the sublimating agent. The formulated floating tablets had increased in-vitro retention time, which indicated potential for sustained release of the drug. If well developed, this may help reduce the oral dosing frequency and encourage patient adherence to the drug therapy.
 Keywords: Non-effervescent, Abelmoschus esculentus, 2-camphanone, floating

Enhancement of catalytic toluene combustion over Pt–Co3O4 catalyst through in-situ metal-organic template conversion

A Pt–Co3O4 catalyst named Pt–Co(OH)2–O was prepared by metal-organic templates (MOTs) conversion and used for catalytic oxidation of toluene. Through the conversion, the morphology of catalysts transformed from rhombic dodecahedron to nanosheet and the coated Pt nanoparticles (NPs) were more exposed. The Binding energy shift in XPS test indicates that the strong metal-support strong interaction (SMSI) has enhanced, and the physicochemical changes caused by it are characterized by other techniques. At the same time, Pt–Co(OH)2–O showed the best catalytic performance (T50 = 157 °C, T90 = 167 °C, Ea = 40.85 kJ mol−1, TOFPt = 2.68 × 10−3 s−1) and good stability. In addition, the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) studies have shown that because SMSI weakened the Co–O bond, the introduction of Pt NPs can make the migration of oxygen in the catalyst easier. The change of binding energy change and the content of various species in the quasi in situ XPS experiment further confirmed that the Pt–Co(OH)2–O catalyst has stronger SMSI, resulting in its stronger electron transfer ability and oxygen migration ability, which is conducive to catalytic reactions. This work provides new ideas for the development of supported catalysts and provides a theoretical reference for the relevant verification of SMSI.

Formulation and Evaluation of Atenolol Nanocrystals Using 3(2) Full Factorial Design

Background: Atenolol is a commonly used antihypertensive drug of class III BCS category. It suffers from the problem of poor intestinal absorption or permeability thus low bioavailability. The objective of the present study was to enhance the permeability of atenolol by using a suitable technique, which is economical and devoid of using any organic solvent. Methods: The nanocrystal technology by high-pressure homogenization was chosen for this purpose, which is a less expensive and simple method. In this technique, no organic solvent was used. The study was further aimed to characterize prepared nanocrystals in the solid state by Fourier Transform Infrared Spectroscopy (FTIR), Powder X-Ray Diffraction (PXRD) patterns, particle size, zeta potential, %yield and drug permeation study through isolated goat’s intestine. An in-vivo study was carried out to determine the pharmacokinetic property in comparison to pure drug powder using rats as experimental animals. The formulation design was optimized by a 3(2) factorial design. In these designs, two factors namely surfactant amount (X1) and speed of homogenizer (X2) were evaluated on three dependent variables namely particle size (y1), zeta potential (y2) and production yield (y3). Results: PXRD study indicated the presence of high crystal content in the prepared formulation. These nanocrystal formulations were found with a narrow size range from 125 nm to 652 nm and positive zeta potential of 16-18 mV. Optimized formulations showed almost 90% production yield. Permeability study revealed 90.88% drug release for optimized formulation in comparison to the pure drug (31.22%). The FTIR study also exposed that there was no disturbance in the principal peaks of the pure drug atenolol. This confirmed the integrity of the pure drug and its compatibility with the excipients used. A significant increase in the area under the concentration-time curve Cpmax and MRT for nanocrystals was observed in comparison to the pure drug. The higher values of the determination coefficient (R2) of all three parameters indicated the goodness of fit of the 3(2) factorial model. The factorial analysis also revealed that speed of homogenizer had a bigger effect on particle size (-0.2812), zeta potential (-0.0004) and production yield (0.0192) whereas amount of surfactant had a lesser effect on production yield (-370.4401), zeta potential (-43.3651) as well as particle size (-6169.2601). Conclusion: It is concluded that the selected method of nanocrystal formation and its further optimization by factorial design was effective to increase the solubility, as well as permeability of atenolol. Further, the systematic approach of factorial design provides rational evaluation and prediction of nanocrystals formulation on the selected limited number of smart experimentation.

Development and evaluation of stimulus-sensitive microgels for controlled drug delivery

The novelty of the present work was focused on the synthesis of pH- and temperature-responsive cross-linked poly(methacrylic acid-co-acrylamide) (p(MAA-co-AM)) microgels for controlled drug delivery. A series of cross-linked microgels was successfully prepared by inverse-suspension polymerization using N,N′-methylenebisacrylamide as a cross-linking agent and potassium persulfate as an initiator. The swelling of the microgels was investigated as a function of pH (2.1 and 7.4) and temperature (20–50°C). The prepared microgels were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy (SEM), particle size analysis and drug-release behavior analysis. FTIR and thermal studies confirmed the formation of a new cross-linked p(MAA-co-AM) polymer. SEM revealed that the microgels were made of spherical, slightly rough and cross-linked particles. To study the controlled-drug-release behavior of microgels, captopril was successfully loaded as a model drug by using an in situ method. The maximum in vitro drug release was up to 96 and 55% at pH 7.4 and 2.1, respectively. All formulations showed pH-dependent drug release following the Higuchi model of drug-release mechanism. In light of the results obtained from the study, it was concluded that p(MAA-co-AM) microgels have potential applications in release of drugs in a controlled manner with respect to pH and temperature.

Polyethylene Glycol (PEG) Modified Porous Ca5(PO4)2SiO4 Bioceramics: Structural, Morphologic and Bioactivity Analysis

Bioceramics are class of biomaterials that are specially developed for application in tissue engineering and regenerative medicines. Sol-gel method used for producing bioactive and reactive bioceramic materials more than those synthesized by traditional methods. In the present research study, the effect of polyethylene glycol (PEG) on Ca5(PO4)2SiO4 (CPS) bioceramics was investigated. The addition of 5% and 10% PEG significantly affected the porosity and bioactivity of sol-gel derived Ca5(PO4)2SiO4. The morphology and physicochemical properties of pure and modified materials were evaluated using scanning electron microscopy (SEM), X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. The effect of PEG on the surface area and porosity of Ca5(PO4)2SiO4 was measured by Brunauer–Emmett–Teller (BET). The results obtained from XRD and FTIR studies confirmed the interactions between PEG and CPS. Due to the high concentration of PEG, the CPS-3 sample showed the largest-sized particle with an average of 200.53 µm. The porous structure of CPS-2 and CPS-3 revealed that they have a better ability to generate an appetite layer on the surface of the sample when immersed in simulated body fluid (SBF) for seven days. The generation of appetite layer showed the bioactive nature of CPS which makes it a suitable material for hard tissue engineering applications. The results have shown that the PEG-modified porous CPS could be a more effective material for drug delivery, implant coatings and other tissue engineering applications. The aim of this research work is to fabricate SBF treated and porous polyethylene glycol-modified Ca5(PO4)2SiO4 material. SBF treatment and porosity of material can provide a very useful target for bioactivity and drug delivery applications in the future.

Preparation and characterization of gel polymer electrolyte based on PVA-K2CO3

ABSTRACT In this study, electrolyte materials were synthesized by mixing a highly conducting salt (K2CO3) with the poly(vinyl alcohol) (PVA) in different proportions (from 10 to 50 wt.%). The synthesized electrolyte was characterized using Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FESEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) for their functional groups, morphology, thermal stability, glass transition temperature (Tg ), ionic conductivity, and potential window, respectively. Characterization results show that the complex formation between PVA and K2CO3 salt has been established by FTIR spectroscopic study, which indicates the detailed interaction between PVA and the salts in PVA-K2CO3 composites while the amorphous nature of the electrolyte after incorporation of the salts has been confirmed by FESEM analysis. Similarly, TGA and DSC analysis revealed that both decomposition temperature and Tg of the synthesized electrolytes decrease with the addition of K2CO3 due to the strong plasticizing effect of the salt. The results confirm that the electrolytes have sufficient thermal stability for supercapacitor operation, as well as an amorphous phase to effectively deliver high ionic conductivity. The highest ionic conductivity of 4.53 × 10−3 S cm−1 at 373 K and potential window of 2.7 V was exhibited by PK30 (30 wt.% K2CO3), which can be considered as high value for solid-state electrolytes which are superior to those electrolytes from PVA salts earlier reported. The results similarly show that the prepared electrolyte is temperature-dependent as conductivity increase with increase in temperature. Based on these properties, it can be imply that the PVA-K2CO3 gel polymer electrolyte (GPE) could be a promising electrolyte candidate for EDLC applications. The results indicate that the PVA-K2CO3 as a new electrolyte material has great potential in practical applications of portable energy-storage devices.

Highly Selective Aromatization of Octane over Pt-Zn/UZSM-5: The Effect of Pt-Zn Interaction and Pt Position.

The effects of Zn-Pt interaction and Pt dispersion over a uniform compact cylindrical shape ZSM-5 (UZSM-5) on the catalytic octane aromatization performance are investigated. The comparison between different Pt- and Zn-modified ZSM-5 catalysts demonstrates the significance of ZSM-5 morphology and, more importantly, the metal distributions on it. For the UZSM-5 support, Pt atoms prefer to occupy the sites within its inner pores, resulting in high selectivity to xylenes during the octane aromatization. The Zn deposit in inner pores and higher dispersion of Pt lead to the spillover of Pt sites to the external surface, which is critical for the activation of octane to produce reaction intermediates that are further converted to aromatics over the inner pore catalytic sites. These effects are evidenced by a diffuse reflection infrared Fourier transform spectroscopy study of CO adsorbed on the catalyst surface. In situ X-ray absorption fine structure spectra are collected to probe the coordination number and the chemical environment of Pt and Zn atoms in the catalysts during the octane aromatization reaction. Pt and Zn are well dispersed and stable during the reaction, and a partial reduction of Pt during the reaction is observed. A theoretical study using the density functional theory method predicts that the reaction and transition-state intermediates upon octane activation are better stabilized by Pt(111) of Pt external surface sites with a smaller activation barrier, indicating their significance in C-H activation. This hypothesis is further evidenced by comparing the octane aromatization performance of various modified catalysts through varying Zn loading, blocking inner pores, and covering the external catalytic sites with SiO2.

Corrosion inhibition of mild steel in hydrochloric acid by leaves extract of Tephrosia purpurea

The poor corrosion resistance of mild steel makes serious issues (on both economical and safety aspects) in many industries and, the use of corrosion inhibitors is the opt solution to combat mild steel corrosion. The present study investigated the corrosion inhibition behavior of Tephrosia purpurea (T. purpurea) leaves extract on mild steel corrosion in 1 N HCl solution using gravimetric, electrochemical and surface morphological techniques such as Potentiodynamic polarization, Electrochemical Impedance technique (EIS), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). The leaves extract of T. purpurea was characterized using UV-Visible (UV-Vis), Fourier-Transform Infrared Spectroscopy (FT-IR) and Gas Chromatography–Mass Spectrometry (GC-MS). The results derived from gravimetric and electrochemical studies showed the ability of T. purpurea as good corrosion inhibitor for mild steel in 1 N HCl, and it has been found that the inhibition efficiency (I.E in %) increases with increase in concentration of leaves extract molecules. The maximum inhibition efficiency of 95.4% was observed at 300 ppm extract concentration, above which there was no drastic change in inhibition efficiency. From Tafel graphs, it is noticed that the T. purpurea leaves extract exhibited mixed-type corrosion inhibition performance, Nyquist and Bode plots confirmed the single charge transfer mechanism of corrosion inhibition process. It was also obtained that, the adsorption of inhibitor molecules obeys Langmuir adsorption isotherm. The inhibition is mainly due to the adsorption of inhibitor molecules on the mild steel electrode surface, which was confirmed by FT-IR, SEM and AFM studies. From all the experimental results, it is concluded that the leaves extract of T. purpurea performed as a good corrosion inhibitor for mild steel in 1 N Hydrochloric acid medium.

Synthesis of Rice Husk-Derived Magnetic Biochar Through Liquefaction to Adsorb Anionic and Cationic Dyes from Aqueous Solutions

Rice husk-mediated magnetic biochar (RH-MBC) was manufactured in the present study by liquefaction method. It is applied on the anionic and cationic dyes to investigate their dye adsorption capacity from aqueous solutions. Characterization of the prepared materials has been conducted by the Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope, energy-dispersive X-ray, transmission electron microscopy, Brunauer–Emmett–Teller, vibrating sample magnetometer and point of zero charge (PZC) analysis. From the analyses, it is revealed that the manufactured RH-MBC is super-magnetic and more porous with higher surface area compared with its parent materials. After investigating the adsorption data with different adsorption isotherm and kinetic models, the data were best-fitted with Freundlich model and pseudo-second-order model. The present material shows higher adsorption capacity for representative cationic dye CV (80.04 mg/g) rather than the anionic dye EBT (5.09 mg/g). From the FTIR, XRD, PZC and isotherm studies, it is revealed that the dyes adsorption onto the RH-MBC mainly happened due to the presence of the functional groups like C–O, Fe3O4, –OH, C=C and C–O. It is concluded that the novel functionalized RH-MBC is an approach to use the waste material (rice husk) to use for wastewater treatment and highly efficient for cationic dyes adsorption. Additionally, due to its super-magnetic properties, it is easily separable by using external magnetic field.

Zinc-tetraphenylporphyrin grafted on functionalised mesoporous SBA-15: synthesis and utilisation for nitroaldol condensation

Functional free-tetraphenylporphyrin (TPP) molecule was prepared by simple one-step method and subsequently zinc ion was introduced in the cavities of TPP (Zn-TPP). The prepared functional free Zn-TPP was grafted by covalent bonding of zinc with amine functionality present on the internal surface of organo-functionalised mesoporous SBA-15 molecular sieves through axial position. The resultant material was completely characterised using various analytical and spectroscopic techniques including Fourier-transform infrared spectroscopy (FT-IR), ultraviolet–visible spectroscopy, proton nuclear magnetic resonance, X-ray powder diffraction, thermo-gravimetry–differential thermal analysis, 13C magic-angle spinning nuclear magnetic resonance (MAS-NMR), N2 physisorption studies, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The presence of organo-functionality and Zn-TPP on the surface was confirmed by conducting 13C MAS-NMR and FT-IR studies. Often, zinc containing functional porphyrin derivatives have shown as potential biological, luminescent properties, whereas in the present studies the functional free Zn-TPP and heterogenised functional-free Zn-TPP materials (SBA-15-AM-Zn-TPP) explored for the first time as catalytic materials for nitroaldol condensation under varying reaction conditions. The present functional free Zn-TPP has an advantage of ease on preparation and strong interaction on the surface linker through axial position, which made it a potential catalyst for aldol condensation and exhibit promising catalytic activity.

In-situ polymerised PLA-SEP bionanocomposites: effect of silanol groups on the properties of PLA

Poly(lactic acid)-Sepiolite bionanocomposites (PLA-SEP BNCs) with different weight percentages of SEP starting from 1 to 7 wt.% were synthesized by following in-situ polymerization technique. BNCs were characterized by fourier transform infrared spectroscopy (FT-IR), wide angle x-ray diffraction (WAXD), 29Si-nuclear magnetic resonance spectroscopy analysis (29Si-NMR). FT-IR studies indicated the existence of hydrogen bonding between SEP and PLA whereas WAXD analysis indicated the formation of BNCs. 29Si-NMR analysis supported existence of hydrogen bonding between SEP and PLA. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) confirmed that there was no significant agglomeration of SEP in BNCs. Upon incorporation of SEP, melting point of PLA increased. Melting point of PLA and SP7 indicated the formation of β- and α- crystals respectively.

Synthesis and Characterization of Silica Aerogel from Rice Husk with Ambient Pressure Drying Method

Rice husk has become global concern due to the environmental problem since it has been dumped and open burned that contributed to the emissions of carbon dioxide to the atmosphere. Therefore, utilization of rice husk to other useable product such as silica aerogel for adsorption has been study recently due to the silica content in rice husk is about 60% and this material is sustainable and cost effective. Silica aerogel was prepared from rice husk ash and dried by using ambient pressure drying method with addition of tetraethyl orthosilicate (TEOS) due to its capability to prevent the gel from crack and increase the porosity of gel to increase the capacity of adsorption process. The silica aerogel was further characterized by using Fourier Transform Infrared spectroscopy (FTIR), Elemental Anaylzer (EA) and Scanning Electron Microscopic (SEM). The results show that the silica aerogel was successfully synthesized using rice husk ash. The FTIR studies reveal that silica aerogel produced consist of amorphous silica with Si-O-Si bonding and stretching’s. From EA analysis, the carbon in the rice husk decreasing when turn into silica aerogel due to the burning of carbon content in the preparation of silica. The SEM studies confirm that the silica aerogel has a porous structure and has ability to for the application adsorption process such as carbon dioxide adsorption, methylene blue adsorption and others application.

Annealed effects of poly- o- toluidine (POT) nanomaterial at different temperatures


 
 
 Poly-O-Toluidine (POT) nanomaterials were prepared by using chemical oxidative polymerization method. The polymerization process was carried out using the monomer o- toluidine (1M), ammonium peroxydisulphate (APS) (0.5M) as oxidant and the dopant sulphuric acid (3M). The resultant polymer materials are heat treated at various temperatures such as 200°C, and 400°C. The prepared POT materials are characterized by using different Spectroscopic techniques, Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet Visible (UV-VIS) Spectrometry, Particle Size Analyser (PSA), and biological application like Anti-Bacterial activities. The FTIR study shows the various functional groups in POT. The optical properties of prepared polymer material band gap, electron transition are calculated by using UV-VIS techniques. The PSA studies are revealed that the measurement of the size distribution of individual particles in a POT nanomaterials. The antibacterial activity of the POT nanomaterials are indicates that the several microorganisms. These POT nanomaterials are used to examines that the Chemical, optical, size of the nanomaterials and antibacterial activity for different Bactria.
 
 

CATIONIC NANOSTRUCTURED LIPID CARRIERS: OPTIMIZATION OF ZETA POTENTIAL AND EVALUATION

Objective: To fabricate, optimize and evaluate, Lipid-based cationic nanoparticulate dispersed system to improve the bio-adhesion property for ophthalmic use.
 Methods: Lipid-based cationic nanoparticulate dispersed system was fabricated by melt emulsification ultrasonication method and Box-Behnken design was utilized for optimization of formulation through the Design-Expert® program. The concentration of stabilizer, liquid lipid and Cetyltrimethylammonium Bromide (CTAB) was selected as variables (factors) while particle size, zeta potential and polydispersity index (PDI) were selected as a response for optimization purpose. Characterization of particle properties was performed using Transmission Electron Microscopy (TEM), Photon correlation spectroscopy (PCS). Fourier-transform infrared spectroscopy (FT-IR) was performed to study chemical interaction among ingredients. Rhodamine B entrapped CNLC formulation was used to study the interaction of NLC and CNLC on a three-dimensional and two-dimensional ocular tissue model for cell uptake and penetration properties.
 Results: Cationic nanostructured lipid carrier system was successfully fabricated by melt emulsification ultrasonication method. Characterization of nanoparticulate system using PCS revealed particle size in the range of 113.1 to 274.2 nm, PDI in a range of 0.147 to 0.280, while zeta potential in the range of 7.2 to 49.8 mV. The validation of statistical design suggested that it was suitable for navigation of design space. TEM imaging confirmed the results of PCS characterization. FT-IR study suggested a minimal chemical interaction among ingredients in CNLC. Confocal laser microscopic imaging for the interaction of NLC and CNLC on a three-dimensional and two-dimensional ocular tissue model revealed good penetration and bio-adhesion properties.
 Conclusion: The fabricated Cationic nanostructured lipid carrier system was found to be the potential ophthalmic novel drug delivery system with good bio-adhesion and penetration properties.

Heterogeneous Chemistry of CaCO3 Aerosols with HNO3 and HCl.

Calcite (CaCO3) aerosols often serve as an idealized proxy for calcium-rich mineral dust. Their use has also previously been proposed for stratospheric solar radiation management (SSRM). Little is known about the heterogeneous chemistry of calcite aerosols with trace gases HNO3 and HCl and therefore their potential impact on stratospheric ozone (O3). Here we report the results of an experimental study of the uptake of HNO3 and HCl onto submicron CaCO3 particles in two different flow reactors. Products and reaction kinetics were observed by impacting aerosolized CaCO3 onto ZnSe windows, exposing them to the reagent gases at a wide range of concentrations, at 296 K and under dry conditions, and analyzing the particles before and after trace gas exposure using Fourier transform infrared spectroscopy (FTIR). A Ca(OH)(HCO3) termination layer was detected in the form of a HCO3- peak in the FTIR spectra, indicating a hydrated surface even under dry conditions. The results demonstrate the reaction of HNO3 with Ca(OH)(HCO3) to produce Ca(NO3)2, water, and CO2. HCl reacted with Ca(OH)(HCO3) to produce CaCl2 and also water and CO2. The depletion of the Ca(OH)(HCO3)/Ca(CO3) signal due to reaction with HNO3 or HCl followed pseudo-first-order kinetics. From the FTIR analysis, the reactive uptake coefficient for HNO3 was determined to be in the range of 0.013 ≤ γHNO3 ≤ 0.14, and that for HCl was 0.0011 ≤ γHCl ≤ 0.012 within the reported uncertainty. The reaction of HCl with airborne CaCO3 aerosols was also studied in an aerosol flow tube coupled with a quadrupole chemical ionization mass spectrometer (CIMS) under similar conditions to the FTIR study, and γHCl was determined to be 0.013 ± 0.001. Following previous modeling studies, these results suggest that the reactions of HCl and HNO3 with calcite in the stratosphere could ameliorate the potential for stratospheric solar radiation management to lead to stratospheric ozone depletion.

Synthesis and Characterization of Naringenin-Loaded Chitosan-Dextran Sulfate Nanocarrier

The present study focused on synthesis and characterization of polymeric nanocarrier for the hydrophobic drug, naringenin (Nar), using chitosan (CS) and dextran sulfate (DS). CSDS-Nar and blank CSDS nanoparticles were prepared by complex coacervation technique. The nanoparticles were characterized by scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), and dynamic light scattering (DLS). Cytotoxicity evaluation of blank CSDS and CSDS-Nar was performed by MTT assay after 24-h incubation. The nanoparticles were observed to have spherical morphology. The size and zeta potential of the CSDS-Nar were ~ 337.2 ± 48.27 nm and − 34.4 ± 7.45 mV, respectively. The interactions between polymer and drug were confirmed by FTIR studies. The in vitro drug release studies showed that 80% of free naringenin was released rapidly at 36 h. On the other hand, 51% naringenin was released from CSDS-Nar at 36 h. MTT assay demonstrated that at higher dose, the cell viability of MCF-7 cells was 45% and 8% after CSDS and CSDS-Nar treatment, respectively. Hence, the empirical findings of the study suggest that CSDS nanocarrier could be utilized as a promising and ideal carrier for delivery of naringenin and similar hydrophobic drugs to cancer cells.

Carvedilol-loaded polyvinylpyrrolidone electrospun nanofiber film for sublingual delivery

The study aimed to prepare and evaluate carvedilol loaded polyvinylpyrrolidone (PVP) and polyethylene glycol 400 (PEG 400) electrospun nanofibers for sublingual drug delivery. The fabricated formulation was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy (FT-IR) and molecular docking techniques. Prepared nanofibers film was analyzed in terms of surface morphology, thickness, folding endurance, and drug release profile. The results indicated that carvedilol was amorphous in the fibers form and an average diameter of 745 ± 57 nm with a smooth cylinder cross-link structure. Both FT-IR and molecular docking studies demonstrated that hydrogen bonding contributed to drug-polymer intermolecular interaction. The drug dissolution and permeation were much higher than those of the physical mixture. Overall the developed fast dissolving electrospun polymeric film is a promising delivery carrier for carvedilol sublingual delivery.

Preparation, Characterization and Antibacterial Evaluation of Soy Protein Isolate Biopolymeric Films Loaded with Nalidixic Acid

Glycerol plasticized soy protein isolate (SPI) films at different contents (1 to 5% w/w w.r.t SPI) of nalidixic acid (NA) were fabricated by solution casting method. SPI films and NA incorporated SPI films were structurally and mechanically characterized by Fourier transform infrared spectroscopy (FTIR) and mechanical properties, respectively. Thermomechanical and water uptake studies were also carried out for NA incorporated SPI films. The results from FTIR study indicated the presence of NA in SPI as evidenced by generation of two additional peaks at 1259 cm− 1 and 800 cm− 1 attributed to C–C stretching vibration and the deformation of the heterocyclic aromatic ring, respectively. At 4% NA, the tensile stress and tensile modulus of SPI films increased from 5.18 MPa to 8.57 MPa and 57.14 MPa to 93.90 MPa, respectively. Antibacterial activity of NA incorporated SPI films against E. coli and L. monocytogenes were studied. The antibacterial studies of NA incorporated SPI film showed the clear zone of inhibition against both the bacteria. Docking studies were performed for SPI in order to evaluate their binding affinity with NA and similar type of aromatic acids such as mandelic and benzilic acid with which SPI films have been prepared earlier by our group. After docking, the ligands in form of aromatic acids were evaluated according to their binding energy and the interaction pattern between SPI and aromatic acids. The docking results indicated that nitrogen containing heterocyclic ring moiety remained intact during interaction of SPI and NA. This work will be helpful in fabricating NA incorporated SPI film from the renewable resources with significant antibacterial properties and reasonable mechanical properties.