scholarly journals Entrapment of α-Amylase in Agar Beads for Biocatalysis of Macromolecular Substrate

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Manu Sharma ◽  
Vinay Sharma ◽  
Dipak K. Majumdar
Keyword(s):  
Thermal Stability ◽  
Half Life ◽  
Thermal Inactivation ◽  
Scale Up ◽  
Physical Stability ◽  
Entrapment Efficiency ◽  
Substrate Affinity ◽  
Michaelis Constant ◽  
Size Dependent ◽  
Temperature Optima

Attempts have been made to optimize immobilization parameters, catalytic property, and stability of immobilized α-amylase in agar. The work compares natural entrapment efficiency of agar with the ionotropically cross-linked agar hydrogel, with the advantage of easy scale-up and cost and time effectiveness. Beads prepared with 3% (w/v) agar and 75 mM calcium chloride and hardened for 20 minutes were selected for further studies on the basis of entrapment efficiency (80%) and physical stability. Following entrapment, pH and temperature optima of enzyme were shifted from 6 to 6.5 and 50 to 55°C, respectively. Michaelis constant (Km) for both free and entrapped enzymes remained the same (0.83%) suggesting no change in substrate affinity. However, Vmax⁡ of entrapped enzyme decreased ~37.5-fold. The midpoint of thermal inactivation for entrapped enzyme increased by 8 ± 1°C implying its higher thermal stability. The entrapped enzyme in calcium agar bead had an Ea value of 27.49 kcal/mol compared to 17.6 kcal/mol for free enzyme indicating increased stability on entrapment. Half-life of enzyme increased ~2.2 times after entrapment in calcium agar at 60°C indicating stabilization of enzyme. The reusability of beads was size dependent. Beads with diameter <710 μm were stable and could be reused for 6 cycles with ~22% loss in activity.

Cationic Diclofenac Lipid Nanoemulsion for Improved Oral Bioavailability: Preparation, Characterization and In Vivo Evaluation

2015 ◽  
Vol 8 (2) ◽  
pp. 2874-2880
Author(s):  
Kishan Veerabrahma ◽  
Swapna Madishetty ◽  
Muzammil Afzal Syed ◽  
Prabhakar Kandadi
Keyword(s):  
Oral Bioavailability ◽  
Physical Stability ◽  
Cationic Lipid ◽  
Entrapment Efficiency ◽  
In Vivo Studies ◽  
Pharmacokinetic Parameters ◽  
In Vivo Evaluation ◽  
Drug Content ◽  
Lipid Nanoemulsion

Cationic nanoemulsions were reported to have increased bioavailability. The aim of present study was to prepare a cationic lipid nanoemulsion of diclofenac acid (LNEs) for improved oral bioavailability to treat arthritic conditions. The LNEs of diclofenac acid were prepared by using soya bean oil, egg lecithin, cholesterol and stearylamine. Stearylamine was used as positive charge inducer. The LNEs were processed by homogenization and ultrasonication. The formulation composition was selected based on earlier reports. The LNEs were characterized for size and zeta potential. The physical stability of LNEs was studied using autoclaving, centrifugal, desorption (dilution effect) stresses and on storage. The total drug content and entrapment efficiency were determined using HPLC. During in vivo studies in Wistar rats, the pharmacokinetic parameters of LNEs were compared with a prepared diclofenac suspension in sodium CMC mucilage. The selected formulations, F1, F2 and F3, were relatively stable during centrifugal stress, dilution stress and on storage. The drug content was found to be 2.38 ± 1.70 mg/ml for F1, 2.30 ± 0.82 mg/ml for F2, and 2.45 ± 0.66 mg/ml for F3. The entrapment efficiencies were 97.83 ± 0.53%, 97.87 ± 1.22% and 98.25 ± 0.21% for F1, F2 and F3 respectively. The cumulative percentage drug release from F1, F2 and F3 showed more release in pH 6.8 phosphate buffer than in pH 1.2 HCl. During oral bioavailability studies, the LNEs showed higher serum concentrations than a suspension. The relative bioavailability of the LNE formulations F1, F2 and F3 were found to be 2.35, 2.94 and 6.28 times that of F4 suspension and were statistically significant. Of all, the cationic lipid nanoemulsion (F3) was superior in improving bioavailability, when compared with plain emulsion (F1) and cholesterol containing LNE (F2). The study helps in designing the cationic oral nanoemulsions to improve the oral bioavailability of diclofenac.

Binding of 3-phosphoglycerate leads to both activation and stabilisation of ADP-glucose pyrophosphorylase from apple leaves

2005 ◽  
Vol 32 (9) ◽  
pp. 839
Author(s):  
Rui Zhou ◽  
Lailiang Cheng
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Enzyme Activity ◽  
Inorganic Phosphate ◽  
Thermal Inactivation ◽  
Specific Activity ◽  
Apple Leaves ◽  
Apparent Homogeneity ◽  
Adp Glucose Pyrophosphorylase ◽  
High Concentrations

Apple leaf ADP-glucose pyrophosphorylase was purified 1436-fold to apparent homogeneity with a specific activity of 58.9 units mg–1. The enzyme was activated by 3-phosphoglycerate (PGA) and inhibited by inorganic phosphate (Pi) in the ADPG synthesis direction. In the pyrophosphorolytic direction, however, high concentrations of PGA (> 2.5 mm) inhibited the enzyme activity. The enzyme was resistant to thermal inactivation with a T0.5 (temperature at which 50% of the enzyme activity is lost after 5 min incubation) of 52°C. Incubation with 2 mm PGA or 2 mm Pi increased T0.5 to 68°C. Incubation with 2 mm dithiothreitol (DTT) decreased T0.5 to 42°C, whereas inclusion of 2 mm PGA in the DTT incubation maintained T0.5 at 52°C. DTT-induced decrease in thermal stability was accompanied by monomerisation of the small subunits. Presence of PGA in the DTT incubation did not alter the monomerisation of the small subunits of the enzyme induced by DTT. These findings indicate that binding of PGA renders apple leaf AGPase with a conformation that is not only more efficient in catalysis but also more stable to heat treatment. The physiological significance of the protective effect of PGA on thermal inactivation of AGPase is discussed.

scholarly journals Preparation, characterization and scale-up of sesamol loaded solid lipid nanoparticles

2012 ◽  
Vol 2 (1) ◽  
pp. 8 ◽  
Author(s):  
Vandita Kakkar ◽  
Indu Pal Kaur
Keyword(s):  
Solid Lipid Nanoparticles ◽  
Scale Up ◽  
Spherical Shape ◽  
Entrapment Efficiency ◽  
Lipid Nanoparticles ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Solid Lipid ◽  
Transmission Electron ◽  
The Brain

Sesamol loaded solid lipid nanoparticles (SSLNs) were prepared with the aim of minimizing its distribution to tissues and achieving its targeting to the brain. Three scale-up batches (100x1 L) of S-SLNs were prepared using a microemulsification technique and all parameters were statistically compared with the small batch (1x;10 mL). S-SLNs with a particle size of less than 106 nm with a spherical shape (transmission electron microscopy) were successfully prepared with a total drug content and entrapment efficiency of 94.26±2.71% and 72.57±5.20%, respectively. Differential scanning calorimetry and infrared spectroscopy confirmed the formation of lipidic nanoparticles while powder X-ray diffraction revealed their amorphous profile. S-SLNs were found to be stable for three months at 5±3°C in accordance with International Conference on Harmonisation guidelines. The SLN preparation process was successfully scaled-up to a 100x batch on a laboratory scale. The procedure was easy to perform and allowed reproducible SLN dispersions to be obtained.

Immobilization of ß-galactosidase from Kluyveromyces lactis on Eupergit® C and Properties of the Biocatalyst

2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Graciella da Silva Campello ◽  
Renata Aguirre Trindade ◽  
Tatiane Vieira Rêgo ◽  
Janaína Fernandes de Medeiros Burkert ◽  
Carlos André Veiga Burkert
Keyword(s):  
Thermal Stability ◽  
Ionic Strength ◽  
Batch Reactor ◽  
Kluyveromyces Lactis ◽  
Immobilized Enzymes ◽  
Maximum Activity ◽  
Lactose Hydrolysis ◽  
Substrate Affinity ◽  
Burman Design ◽  
Plackett Burman Design

Abstract The main goal of this study was to investigate the immobilization of commercial ß-galactosidase from Kluyveromyces lactis (Lactozym®) on Eupergit® C. A Plackett-Burman design was proposed. The ionic strength and pH were the variables that presented significant effect (p<0.1) on immobilization. The increase in the ionic strength from 0.1 to 1.5 M and the increase in pH from 6.6 to 7.4 represented an increase of 28.56% and a reduction of 18.19% in the immobilization yield, respectively. At 25°C, pH 6.6, ionic strength of 1.5 M, immobilization for 8 h, 1 mM of divalent magnesium ion and 0.4 mL of enzyme added, reached 85% immobilization yield. The free and immobilized enzymes were characterized. pH and temperature profiles showed maximum activity at pH 6.6 and 45°C, for both free and immobilized enzymes. There was a gain in thermal stability with enzyme immobilization and there was an increase of about four times in the half-life of the immobilized derivative at 45°C (from 0.43 h to 1.78 h). This greater thermal stability was also made clear through the calculation of thermodynamic parameters (ΔH, ΔG and ΔS). Km values, 30.33 mM and 104.00 mM for free and immobilized enzymes, respectively, represented a reduction in substrate affinity after immobilization, possibly owing to stereo-conformational factors. In a batch reactor for lactose hydrolysis from cheese whey, an increase in lactose conversion with immobilization was observed at 40°C and 45°C (90.43% and 65.36%, respectively) in relation to the free enzyme (84.17% and 39.58%, respectively).

scholarly journals Immobilization of Mutant Phosphotriesterase on Fuller’s Earth Enhanced the Stability of the Enzyme

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 983
Author(s):  
Wahhida Latip ◽  
Victor Feizal Knight ◽  
Ong Keat Khim ◽  
Noor Azilah Mohd Kasim ◽  
Wan Md Zin Wan Yunus ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Metal Ions ◽  
Half Life ◽  
Industrial Applications ◽  
Free Enzyme ◽  
High Tolerance ◽  
Tween 40 ◽  
Fuller’S Earth ◽  
The Stability ◽  
Biochemical Features

Immobilization is a method for making an enzyme more robust in the environment, especially in terms of its stability and reusability. A mutant phosphotriesterase (YT PTE) isolated from Pseudomonas dimunita has been reported to have high proficiency in hydrolyzing the Sp and Rp-enantiomers of organophosphate chromophoric analogs and therefore has great potential as a decontamination agent and biosensor. This work aims to investigate the feasibility of using Fuller’s earth (FE) as a YT PTE immobilization support and characterize its biochemical features after immobilization. The immobilized YT PTE was found to show improvement in thermal stability with a half-life of 24 h compared to that of the free enzyme, which was only 8 h. The stability of the immobilized YT PTE allowed storage for up to 4 months and reuse for up to 6 times. The immobilized YT PTE showed high tolerance against all tested metal ions, Tween 40 and 80 surfactants and inorganic solvents. These findings showed that the immobilized YT PTE became more robust for use especially with regards to its stability and reusability. These features would enhance the future applicability of this enzyme as a decontamination agent and its use in other suitable industrial applications.

scholarly journals Preparation of PP-g-(AA-MAH) Fibers Using Suspension Grafting and Melt-Blown Spinning and its Adsorption for Aniline

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2157
Author(s):  
Zhouyang Lian ◽  
Yiyang Xu ◽  
Jie Zuo ◽  
Hui Qian ◽  
Zhengwei Luo ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nuclear Magnetic Resonance ◽  
Scale Up ◽  
Deionized Water ◽  
Optimal Conditions ◽  
Functional Monomers ◽  
Grafting Ratio ◽  
Spectroscopic Analyses ◽  
The Matrix ◽  
Monomer Content

This paper uses polypropylene (PP) as the matrix and acrylic acid (AA) and maleic anhydride (MAH) as functional monomers to prepare PP-g-(AA-MAH) fibers by suspension grafting and melt-blown spinning technology that are easy to industrially scale-up. The fibers can be used to adsorb aniline. Results showed that the grafting ratio reached the maximum of 12.47%. The corresponding optimal conditions were grafting time of 3 h, AA: MAH = 0.75, total monomer content of 55%, benzoyl peroxide 1.4%, xylene concentration of 6 mL/g PP, and deionized water content of 8 mL/g PP. Owing to its good fluidity and thermal stability, the product of suspension grafting can be used for melt-blown spinning. Infrared spectroscopic and nuclear magnetic resonance spectroscopic analyses indicated that AA and MAH were successfully grafted onto PP fibers. After grafting, the hydrophilicity of PP-g-(AA-MAH) fiber increased. Therefore, it had higher absorptivity for aniline and the adsorption capacity could reach 42.2 mg/g at 45 min and pH = 7. Moreover, the PP-g-(AA-MAH) fibers showed good regeneration performance.

A COMPARATIVE ASSESSMENT OF VESICULAR FORMULATIONS: TRANSFERSOMES AND CONVENTIONAL LIPOSOMES LOADED IVABRADINE HYDROCHLORIDE

2020 ◽  
pp. 51-55
Author(s):  
GITA CHAURASIA ◽  
NARENDRA LARIYA
Keyword(s):  
Drug Release ◽  
Physical Stability ◽  
Physical Appearance ◽  
Spherical Shape ◽  
Entrapment Efficiency ◽  
Tween 80 ◽  
Molar Ratio ◽  
Drug Release Study ◽  
Release Study

Objective: Ivabradine hydrochloride (IH), a benzazepine derivative used to treat cardiovascular disease angina pectoris. In this study IH-loaded novel carrier systems transfersomes (TFs) and conventional liposomes (CLs) were developed and compared for their efficacy to enhance the stability of drugs from degradation. Methods: TFs formulations (TF-1, TF-2 and TF-3) were prepared by using different biocompatible surfactants; tween-80 (TW), span-80(S) and sodium deoxycholate (SC) in the concentration ratio of 15 parts with 85 parts of soy phosphatidylcholine as phospholipid by thin-film hydration method. These vesicles were compared with CLs formulation (L-1) prepared in 7:3 molar ratio of soy phosphatidylcholine: cholesterol by following the same method. These vesicles were compared for physical appearance, vesicle shape, and size, percentage drug entrapment efficiency (%DEE), deformability index (DI), in vitro percentage cumulative drug release study, and physical stability studies. The chosen optimized novel carriers were observed under scanning electron microscopy. Results: The compared data demonstrated that the physical appearance for all vesicles was turbid and had a spherical shape. The size distribution was in the range of 129.0 nm to 273.5 nm in vesicles. The %DEE (79.0±0.94) and DI (35.0±1.9) was found maximum in TF-1 formulation that was 2.3 times higher than L-1 formulation. The in vitro percentage cumulative drug release study followed second-order polynomial kinetics that was 2.0 times higher than L-1and 2.9 times higher than the plain drug in 30 min (90.4±0.06%) from TF-1. The vesicles were found to be stable at refrigeration conditions. Conclusion: Thus, amongst of all vesicles TW loaded TFs (TF-1) was chosen as an excellent novel vesicular carrier for hydrophilic drugs due to its higher deformability behavior than CLs that protects the certain drugs from biodegradation and provides stability.

scholarly journals Studies in Finishing Effects of Clay Mineral in Polymers and Synthetic Fibers

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Faheem Uddin
Keyword(s):  
Thermal Stability ◽  
Clay Mineral ◽  
Physical Stability ◽  
Polymeric Materials ◽  
Strength Properties ◽  
Research Literature ◽  
Synthetic Fibers ◽  
Peak Heat Release Rate ◽  
Recent Modification ◽  
Significant Research

The use of clay mineral in modifying the properties of polymeric material is improved in application. The current interest in modifying the polymeric materials, particularly polyethylene, polypropylene, polystyrene, and nylon using clay mineral for improved flame retardancy, thermal stability, peak heat release rate, fracture, and strength properties generated significant research literature. This paper aims to review some of the important recent modification achieved in the performance of polymeric materials using organoclay mineral. Degradation of clay mineral-polymer (nm) composite is discussed with appropriate known examples. Clay mineral (nm) loading of 5 wt.% to 7 wt.% that was significantly smaller than the percent loading of conventional fillers in polymeric materials introduced significant improvement in terms of thermal and physical stability. An attempt is made to emphasize flammability and thermal stability and to indicate the areas that are relatively little explored in modification of fiber-forming polymers to enhance further research interest.

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