Is centrifugal ultrafiltration a robust method for determining encapsulation efficiency of pesticide nanoformulations?

Nanoscale ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 5410-5418
Author(s):  
Rocío López-Cabeza ◽  
Melanie Kah ◽  
Renato Grillo ◽  
Zuzana Bílková ◽  
Jakub Hofman
Keyword(s):  
Encapsulation Efficiency ◽  
Robust Method ◽  
Centrifugal Ultrafiltration

Encapsulation efficiency of nanoformulated pesticides is often determined by centrifugal ultrafiltration.

Optimization and Characterization of Aqueous Micellar Formulations for Ocular Delivery of an Antifungal Drug, Posaconazole

2020 ◽  
Vol 26 (14) ◽  
pp. 1543-1555 ◽  
Author(s):  
Meltem E. Durgun ◽  
Emine Kahraman ◽  
Sevgi Güngör ◽  
Yıldız Özsoy
Keyword(s):  
Particle Size ◽  
Zeta Potential ◽  
Size Distribution ◽  
Encapsulation Efficiency ◽  
Fungal Infections ◽  
In Vitro Release ◽  
Pluronic F127 ◽  
Glycol Succinate ◽  
Vitro Release

Background: Topical therapy is preferred for the management of ocular fungal infections due to its superiorities which include overcoming potential systemic side effects risk of drugs, and targeting of drugs to the site of disease. However, the optimization of effective ocular formulations has always been a major challenge due to restrictions of ocular barriers and physiological conditions. Posaconazole, an antifungal and highly lipophilic agent with broad-spectrum, has been used topically as off-label in the treatment of ocular fungal infections due to its highly lipophilic character. Micellar carriers have the potential to improve the solubility of lipophilic drugs and, overcome ocular barriers. Objective: In the current study, it was aimed optimization of posaconazole loaded micellar formulations to improve aqueous solubility of posaconazole and to characterize the formulations and to investigate the physical stability of these formulations at room temperature (25°C, 60% RH), and accelerated stability (40°C, 75% RH) conditions. Method: Micelles were prepared using a thin-film hydration method. Pre-formulation studies were firstly performed to optimize polymer/surfactant type and to determine their concentration in the formulations. Then, particle size, size distribution, and zeta potential of the micellar formulations were measured by ZetaSizer Nano-ZS. The drug encapsulation efficiency of the micelles was quantified by HPLC. The morphology of the micelles was depicted by AFM. The stability of optimized micelles was evaluated in terms of particle size, size distribution, zeta potential, drug amount and pH for 180 days. In vitro release studies were performed using Franz diffusion cells. Results: Pre-formulation studies indicated that single D-ɑ-tocopheryl polyethylene glycol succinate (TPGS), a combination of it and Pluronic F127/Pluronic F68 are capable of formation of posaconazole loaded micelles at specific concentrations. Optimized micelles with high encapsulation efficiency were less than 20 nm, approximately neutral, stable, and in aspherical shape. Additionally, in vitro release data showed that the release of posaconazole from the micelles was higher than that of suspension. Conclusion: The results revealed that the optimized micellar formulation of posaconazole offers a potential approach for topical ocular administration.

Improving Topical Skin Delivery of Monocrotaline Via Liposome Gel-based Nanosystems

2019 ◽  
Vol 16 (10) ◽  
pp. 940-950 ◽  
Author(s):  
Jiandong Yu ◽  
Zhi Chen ◽  
Yan-zhi Yin ◽  
Chaoyuan Tang ◽  
Enying Hu ◽  
...  
Keyword(s):  
Gradient Method ◽  
Encapsulation Efficiency ◽  
Ph Value ◽  
Topical Administration ◽  
Ph Gradient ◽  
Stability Factor ◽  
Buffer Solution ◽  
Skin Delivery ◽  
Skin Retention

Background: In this study, a liposomal gel based on a pH-gradient method was used to increase the skin-layer retention of monocrotaline (MCT) for topical administration. Methods: Using the Box-Behnken design, different formulations were designed to form liposome suspensions with optimal encapsulation efficiency (EE%) and stability factor (KE). In order to keep MCT in liposomes and accumulate in skin slowly and selectively, MCT liposome suspensions were engineered into gels. Results: A pH-gradient method was used to prepare liposome suspensions. The optimal formulation of liposome suspensions (encapsulation efficiency: 83.10 ± 0.21%) was as follows: MCT 12 mg, soybean phosphatidyl choline (sbPC) 200 mg, cholesterol (CH) 41 mg, vitamin E (VE) 5 mg, and citric acid buffer solution (CBS) 4.0 10 mL (pH 7.0). The final formulation of liposomal gels consisted of 32 mL liposome suspensions, 4.76 mL deionized water, 0.40 g Carbopol-940, 1.6 g glycerol, 0.04 g methylparaben, and a suitable amount of triethanolamine for pH value adjustment. The results of in vitro drug release showed that MCT in liposomal gels could be released in 12 h constantly in physiological saline as a Ritger-Peppas model. Compared with plain MCT in gel form, liposomal MCT in gel had higher skin retention in vitro. Conclusion: In this study, liposomal gels were formed for greater skin retention of MCT. It is potentially beneficial for reducing toxicities of MCT by topical administration with liposomal gel.

A Simplified Protocol for the Stereospecific Nickel-Catalyzed C–S Vinylation Using NiX2 Salts and Alkyl Phosphites

Synthesis ◽  
2019 ◽  
Vol 52 (02) ◽  
pp. 311-319
Author(s):  
Austin D. Marchese ◽  
Bijan Mirabi ◽  
Egor M. Larin ◽  
Mark Lautens
Keyword(s):  
Cross Coupling ◽  
Robust Method ◽  
Alkyl Phosphites

A Ni-catalyzed C–S cross-coupling using only NiI2 (0.5–2.5 mol%) and P(OiPr)3 (2.0–10.0 mol%) is reported. Using an air-stable Ni(II) precatalyst, and a cheap and commercially available ligand, a scalable and robust method was developed to cross-couple various thiophenols and styryl bromides, including some sterically encumbered thiols, an α-bromocinnamaldehyde as well as a thiolation-cyclization.

scholarly journals Microencapsulation ofβ-Carotene by Spray Drying: Effect of Wall Material Concentration and Drying Inlet Temperature

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Luiz C. Corrêa-Filho ◽  
Maria M. Lourenço ◽  
Margarida Moldão-Martins ◽  
Vítor D. Alves
Keyword(s):  
Antioxidant Activity ◽  
Spray Drying ◽  
Encapsulation Efficiency ◽  
Fruits And Vegetables ◽  
Wall Material ◽  
Inlet Temperature ◽  
Carotene Content ◽  
Arabic Gum ◽  
Air Inlet ◽  
Adverse Environmental Conditions

Carotenoids are a class of natural pigments found mainly in fruits and vegetables. Among them,β-carotene is regarded the most potent precursor of vitamin A. However, it is susceptible to oxidation upon exposure to oxygen, light, and heat, which can result in loss of colour, antioxidant activity, and vitamin activity. Thus, the objective of this work was to study the microencapsulation process ofβ-carotene by spray drying, using arabic gum as wall material, to protect it against adverse environmental conditions. This was carried out using the response surface methodology coupled to a central composite rotatable design, evaluating simultaneously the effect of drying air inlet temperature (110-200°C) and the wall material concentration (5-35%) on the drying yield, encapsulation efficiency, loading capacity, and antioxidant activity. In addition, morphology and particles size distribution were evaluated. Scanning electron microscopy images have shown that the particles were microcapsules with a smooth surface when produced at the higher drying temperatures tested, most of them having a diameter lower than 10μm. The conditions that enabled obtaining simultaneously arabic gum microparticles with higherβ-carotene content, higher encapsulation efficiency, and higher drying yield were a wall material concentration of 11.9% and a drying inlet temperature of 173°C. The systematic approach used for the study ofβ-carotene microencapsulation process by spray drying using arabic gum may be easily applied for other core and wall materials.

scholarly journals Patch antenna sensor for wireless ice and frost detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryan Kozak ◽  
Kasra Khorsand ◽  
Telnaz Zarifi ◽  
Kevin Golovin ◽  
Mohammad H. Zarifi
Keyword(s):  
Resonant Frequency ◽  
Patch Antenna ◽  
Wide Band ◽  
Power Lines ◽  
Ice Thickness ◽  
Ice Accretion ◽  
Robust Method ◽  
Frequency Shifts ◽  
Resonant Amplitude ◽  
Recorded Data

AbstractA patch antenna sensor with T-shaped slots operating at 2.378 GHz was developed and investigated for wireless ice and frost detection applications. Detection was performed by monitoring the resonant amplitude and resonant frequency of the transmission coefficient between the antenna sensor and a wide band receiver. This sensor was capable of distinguishing between frost, ice, and water with total shifts in resonant frequency of 32 MHz and 36 MHz in the presence of frost and ice, respectively, when compared to the bare sensor. Additionally, the antenna was sensitive to both ice thickness and the surface area covered in ice displaying resonant frequency shifts of 2 MHz and 8 MHz respectively between 80 and 160 μL of ice. By fitting an exponential function to the recorded data, the freezing rate was also extracted. The analysis within this work distinguishes the antenna sensor as a highly accurate and robust method for wireless ice accretion detection and monitoring. This technology has applications in a variety of industries including the energy sector for detection of ice on wind turbines and power lines.

641 What Is the Most Reliable Way to Secure A Surgical Drain?

2021 ◽  
Vol 108 (Supplement_2) ◽  
Author(s):  
B Hughes ◽  
J Stallard ◽  
S Jivan
Keyword(s):  
Suture Material ◽  
Suture Techniques ◽  
Robust Method ◽  
Suturing Technique ◽  
The Moment ◽  
Tissue Reactions ◽  
Surgical Drain

Abstract Introduction Surgical drains are used by many specialities, we aim to determine the most robust method of securing them by comparing suturing technique, material and fixation angle. Method A Blake’s drain was inserted into a piece of pork belly and secured using a standard ‘three half hitch’ technique with 3.0 Silk, EthilonTM and ProleneTM . For each suture type, drains were sutured in line, at 45 and 90 degrees to the course of the drain. The force needed for the suture to failure was measured and each repeated 3 times. Different suture techniques were then used to determine the strongest fixation. Results With the drain exiting inline the moment of failure was, on average, 1.25kg for silk, 3.5kg for EthilonTM and 4.0kg for ProleneTM. Increasing drain fixation angle required more force for the suture to fail. With EthilonTM and ProleneTM, the suture snapped before the drain slipped. Three half hitches was the strongest technique. Conclusions Suture material, technique and drain fixation angle had an impact on suture strength with ProleneTM outperforming Silk. We advocate using a ‘three half hitch’ technique with 3.0 ProleneTM to secure a surgical drain. It offers superior strength whilst reducing the risk of localised tissue reactions.

Ultrasonic cavitation driven fabrication of organic solvent free lignin/prochloraz nano capsules to promote resistance to photolysis and rain wash, and provide extended release performance

Holzforschung ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jingtian Chen ◽  
Miao Wang ◽  
Yong Qian ◽  
Shanyuan Tan ◽  
Huan Wang ◽  
...  
Keyword(s):  
Organic Solvent ◽  
Uv Irradiation ◽  
Encapsulation Efficiency ◽  
Extended Release ◽  
Ultrasonic Cavitation ◽  
Solvent Free ◽  
Loading Capacity ◽  
One Pot ◽  
Continuous Release ◽  
Mango Leaves

Abstract Lignin is a natural macromolecular sun blocker and provides an ideal protection material for pesticides that have poor photostability. In this study, alkali lignin/prochloraz capsules (AL-P) were prepared via one-pot ultrasonic cavitation. The results demonstrated that the produced AL-P were uniform spheres with sizes of 170–375 nm. The prochloraz encapsulation efficiency (EE) and loading capacity (LC) reached as high as 91.8 and 98.5%, respectively. Adding a small of surfactant reduced the size of the capsules, but both EE and LC were decreased. AL-P exhibited excellent extended release performance. The cumulative release of AL-P in the first 45 h was 76.1% and continuous release was maintained after 96 h. The resulting AL-P have improved photostability under UV irradiation radiation. Finally, AL-P capsules were sprayed on the mango leaves and bananas to act as preservatives, AL-P capsules had stronger rain wash resistance and were better preserved demonstrating their industrial applicability. Together, organic solvent free AL-P capsules demonstrate a method to improve the efficiency of photosensitive pesticides.

scholarly journals Mixing Oil-Based Microencapsulation of Garlic Essential Oil: Impact of Incorporating Three Commercial Vegetable Oils on the Stability of Emulsions

Foods ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1637
Author(s):  
Yunjiao Zhao ◽  
Rui Liu ◽  
Cuiping Qi ◽  
Wen Li ◽  
Mohamed Rifky ◽  
...  
Keyword(s):  
Essential Oil ◽  
Vegetable Oils ◽  
Encapsulation Efficiency ◽  
Ostwald Ripening ◽  
Corn Oil ◽  
Whey Protein Concentrate ◽  
Diallyl Disulfide ◽  
Active Components ◽  
The Stability ◽  
Garlic Essential Oil

The active components in garlic essential oil are easily degradable, which limits its application in the food industry. Vegetable oils (VOs) were used to improve the stability of garlic essential oil (GEO) emulsion. The volatile compounds of GEO and its mixtures with vegetable oils (VOs), including corn oil (CO), soybean oil (SO), and olive oil (OO) indicated that GEO-VO mixtures had a higher percentage of Diallyl disulfide and Diallyl trisulfide than pure GEO. Adding an appropriate amount of VOs promoted the GEO emulsion (whey protein concentrate and inulin as the wall materials) stability in order of CO > SO > OO. Evaluation of the encapsulation efficiency, controlled release, and antimicrobial activity of GEO-VO microcapsules showed that the GEO was successfully entrapped and slowly released with active antibacterial activities on both E. coli and S. aureus. Collectively, these results implied that VOs, especially for 20% CO, improved the stability of GEO emulsions and the encapsulation efficiency of GEO microcapsules. The mechanism might be related to (1) the regulating effect of density difference between oil and water phases on prevention to gravitational separation, (2) the promotion to the compatibility of GEO and VOs to inhibit the phase separation caused by Ostwald ripening.

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