Solidifying Essential Balm into Electrospun Core-sheath Nanofibers for Prolonged Release

2020 ◽  
Vol 1 (1) ◽  
pp. 122-131
Author(s):  
Kun Zhao ◽  
Yao-Yao Yang ◽  
Shi-Xiong Kang ◽  
Deng-Guang Yu
Keyword(s):  
Shelf Life ◽  
Rate Ratio ◽  
Physical Stability ◽  
Core Layer ◽  
Flow Rate Ratio ◽  
Prolonged Release ◽  
Slowing Down ◽  
The Core ◽  
High Volatility ◽  
Microscopy Images

Background: Essential Balm (EB) is a commonly used medicine with high volatility and short shelf-life during storage. Objective: Slowing down the volatilization rate of EB and exploring the effect of fiber on the volatilization rate of EB. Methods: In this study, electrospinning technology was used to convert the liquid EB into solid EB in order to improve the balm’s storage and longevity. Results: Specifically, core-sheath nanofibers coated with EB were prepared by traditional coaxial electrospinning technology, in which polyvinylpyrrolidone K90 was used as polymer sheath to reduce the volatilization of EB in the core layer. Scanning electron microscopy images showed that the core-sheath flow rate ratio is proportional to the sizes and number of spindles. EB was successfully placed into the fibers and showed good compatibility with the carriers. Infrared spectroscopy indicated the presence of a hydrogen bond between them. Volatility tests showed that all prepared composites could delay the volatility of EB and improve its physical stability. Conclusion: This methodology can be applied toward increasing the shelf-life of liquid drugs by using core-sheath nanofibers. The core-sheath fibers with good morphology are more propitious to delay the volatilization rate of EB.

Determination of flow rate ratio for plate valve operating in two-phase medium

1989 ◽  
Vol 25 (7) ◽  
pp. 394-396
Author(s):  
V. E. Shcherba ◽  
I. S. Berezin ◽  
S. S. Danilenko ◽  
I. E. Titov ◽  
P. P. Filippov
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Flow Rate Ratio ◽  
Two Phase ◽  
Plate Valve ◽  
Phase Medium

Effect of the argon/monomer flow-rate ratio on the flowability trend of PECVD-processed micropowder

2017 ◽  
Vol 328 ◽  
pp. 480-487 ◽  
Author(s):  
V.R. Giampietro ◽  
M. Gulas ◽  
P. Rudolf von Rohr
Keyword(s):  
Flow Rate ◽  
Rate Ratio ◽  
Flow Rate Ratio

scholarly journals Effect of Shelf Life on the Physical Stability of Suspended Ophthalmic Solutions

2021 ◽  
Vol 141 (6) ◽  
pp. 869-876
Author(s):  
Yuichiro Nakada ◽  
Mizuki Yamaguchi ◽  
Saori Deguchi ◽  
Kazunori Inaba ◽  
Noriaki Nagai
Keyword(s):  
Shelf Life ◽  
Physical Stability ◽  
Ophthalmic Solutions

Face Wrinkling and Core Strength in Sandwich Construction

1960 ◽  
Vol 64 (591) ◽  
pp. 164-167 ◽  
Author(s):  
S. Yusuff
Keyword(s):  
High Stress ◽  
Core Layer ◽  
High Strength ◽  
Bending Rigidity ◽  
Core Strength ◽  
Surface Smoothness ◽  
Lightweight Material ◽  
The Core ◽  
Sandwich Construction ◽  
Strength Material

The effect of initial waviness on the wrinkling of faces in sandwich construction is studied. Formulae are derived to determine the failing stress when the faces wrinkle due to failure of the core in tension, compression or shear. The importance of core strength requirements in maintaining surface smoothness is noted. A comparison of theory with experiments is made, and the agreement between the two is found to be reasonably good.A sandwich construction consists of two thin face layers of high-strength material and a thick core layer of lightweight material. The function of the core is twofold. Firstly, it increases the bending rigidity of the faces and second, it stabilises them so that they will not wrinkle until high stress is reached.

Free Vibration Analysis of Symmetric Sandwich Beams

2017 ◽  
Vol 872 ◽  
pp. 399-404
Author(s):  
Zakaria Ibnorachid ◽  
Khalid El Bikri ◽  
Lhoucine Boutahar
Keyword(s):  
Sandwich Beam ◽  
Free Vibration Analysis ◽  
Core Layer ◽  
Equation Of Motion ◽  
Geometrical Parameters ◽  
Symmetric Vibration ◽  
Materials Properties ◽  
The Core ◽  
Validation Of Results ◽  
Good Agreement

The aim of the present work is to study the linear free symmetric vibration of three-layer sandwich beam using the energy method. The zigzag model is used to describe the displacement field. The theoretical model is based on the top and bottom layers behave as Euler-Bernoulli beams while the core layer as a Timoshenko beam. Based on Hamilton’s principle, the governing equation of motion sandwich beam is obtained in order to calculate the linear frequency parameters. Two types of boundary conditions simple supported-simple-supported (SS-SS) and clamped-clamped (C-C) under the influence of materials properties and geometrical parameters are studied. The validation of results is done by comparing with another studies, which available in the literature and found good agreement between the studies.

Fabrication of Gellan Gum Tubular Structure Using Coaxial Needles: A Study on Wall Thickness and Encapsulation

2018 ◽  
Author(s):  
Ilhan Yu ◽  
Roland Chen ◽  
Samantha Grindrod
Keyword(s):  
Wall Thickness ◽  
Rate Ratio ◽  
Gellan Gum ◽  
Flow Rate Ratio ◽  
Tubular Structures ◽  
Extrusion Speed ◽  
Extrusion Rate ◽  
Coaxial Needle ◽  
Thermal Crosslinking ◽  
Phosphate Buffered Saline

Tubular structures of hydrogel are used in a variety of applications such as 3D cell culturing for delivery of nutrient supplies. The wall thickness of the tube determines the speed of diffusion or delivery rate. In this study, we aimed to fabricate tubular structures with varying of wall thicknesses using a thermal-crosslinking hydrogel, gellan gum, with the coaxial needle approach. The wall thickness is controlled by changing the flow rate ratio between the inner (phosphate-buffered saline) and outer needles (gellan gum). A simulation model was developed to estimate the proper extrusion speed to allow the gellan gum to be extruded around its glass transition temperature. While keeping the extrusion rate of gellan gum fixed, different PBS extrusion rates were tested to investigate the printability to form continuous tubular structures, range of printable wall thickness, and possibility to form tubes with closed ends to encapsulate fluid or drug inside the tube. The ranges of printable wall thickness with two pairs of coaxial needle were identified. It was found that at about 200% of the baseline PBS extrusion speed, a maximum of 20% difference in wall thickness can be achieved, while a close end can still be formed.

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