Process Parameter Optimization of a Polymer Derived Ceramic Coatings for Producing Ultra-High Gas Barrier

Silica is one of the most efficient gas barrier materials, and hence is widely used as an encapsulating material for electronic devices. In general, the processing of silica is carried out at high temperatures, i.e., around 1000 °C. Recently, processing of silica has been carried out from a polymer called Perhydropolysilazane (PHPS). The PHPS reacts with environmental moisture or oxygen and yields pure silica. This material has attracted many researchers and has been widely used in many applications such as encapsulation of organic light-emitting diodes (OLED) displays, semiconductor industries, and organic solar cells. In this paper, we have demonstrated the process optimization of the conversion of the PHPS into silica in terms of curing methods as well as curing the environment. Various curing methods including exposure to dry heat, damp heat, deep UV, and their combination under different environments were used to cure PHPS. FTIR analysis suggested that the quickest conversion method is the irradiation of PHPS with deep UV and simultaneous heating at 100 °C. Curing with this method yields a water permeation rate of 10−3 g/(m2⋅day) and oxygen permeation rate of less than 10−1 cm3/(m2·day·bar). Rapid curing at low-temperature processing along with barrier properties makes PHPS an ideal encapsulating material for organic solar cell devices and a variety of similar applications.

Luteolin-Loaded Elastic Liposomes for Transdermal Delivery to Control Breast Cancer: In Vitro and Ex Vivo Evaluations

The study aimed to prepare and optimize luteolin (LUT)-loaded transdermal elastic liposomes (LEL1-LEL12), followed by in vitro and ex vivo evaluations of their ability to control breast cancer. Various surfactants (Span 60, Span 80, and Brij 35), and phosphatidyl choline (PC) as a lipid, were used to tailor various formulation as dictated by “Design Expert® software (DOE). These were characterized for size, polydispersity index (PDI), and zeta potential. The optimized formulation (OLEL1) was selected for comparative investigations (in vitro and ex vivo) against lipo (conventional liposomes) and drug suspension (DS). Moreover, the in vitro anticancer activity of OLEL1 was compared against a control using MCF-7 cell lines. Preliminary selection of the suitable PC: surfactant ratio for formulations F1–F9 showed relative advantages of Span 80. DOE suggested two block factorial designs with four center points to identify the design space and significant factors. OLEL1 was the most robust with high functional desirability (0.95), minimum size (202 nm), relatively high drug release, increased drug entrapment (92%), and improved permeation rate (~3270 µg/cm2) as compared with liposomes (~1536 µg/cm2) over 24 h. OLEL1 exhibited a 6.2- to 2.9-fold increase in permeation rate as compared with DS (drug solution). The permeation flux values of OLEL1, and lipo were found to be 136.3, 64 and 24.3 µg/h/cm2, respectively. The drug disposition values were 670 µg, 473 µg and 148 µg, for OLEL1, lipo and DS, respectively. Thus, ex vivo parameters were significantly better for OLEL1 compared with lipo and DS which is attributed to the flexibility and deformability of the optimized formulation. Furthermore, OLEL1 was evaluated for anticancer activity and showed maximized inhibition as compared with DS. Thus, elastic liposomes may be a promising approach for improved transdermal delivery of luteolin, as well as enhancing its therapeutic efficacy in controlling breast cancer.

CFD Simulation of Syngas Combustion in a Two-Pass Oxygen Transport Membrane Reactor for Fire Tube Boiler Application

The oxygen transport membrane reactor technology enables the stable combustion of syngas and reduction in NOx emission. Applying the syngas combustion membrane reactor to fire tube boiler can integrate oxygen separation, syngas combustion, and steam generation in a single apparatus. In this study, a CFD model for oxygen permeation and syngas combustion in a two-pass LSCoF-6428 tubular membrane reactor for fire tube boiler application was developed to study the effects of the inlet temperature, the sweep gas flow rate, and the syngas composition on the reactor performance. It is shown that the inlet temperature has a strong effect on the reactor performance. Increasing the inlet temperature can efficiently and significantly improve the oxygen permeability and the heat production capacity. A 34-times increase of oxygen permeation rate and a doubled thermal power output can be obtained when increasing the inlet temperature from 1073 to 1273 K. The membrane temperature, the oxygen permeation rate, and the thermal power output of the reactor all increase with the increase of sweep gas flow rate or H2/CO mass ratio in syngas. The feasibility of the syngas combustion membrane reactor for fire tube boiler application was elucidated.

Simulation and experiment analysis of relationship between voids and permeability of composites

Due to the significant weight reduction advantage, aerospace composite tanks have become the focus of international competition of spacecraft. However, the permeation of small molecules at low temperature caused by the internal voids of composites is one of the key technical problems which restrict the engineering application of composite tanks. In this study, a combination of theoretical research and experimental research was adopted. By changing the curing pressures of the composites’ autoclave process, laminates with different porosities were prepared and tested for low-temperature permeability. Based on the grayscale processing and median filtering methods, a permeability prediction model with the true voids morphology of composite materials was established. Based on the random medium theory, the random voids model of composites was built to study the effect of void size and shape on the permeability of laminates. The results showed that the finite element analysis of composites, permeability based on the real voids morphology model was in good agreement with the experimental results, which proved the feasibility of this method. The permeation rate of laminates increased with the raised of porosity, and the internal porosity of the laminates could be diminished by improving the curing pressure so as to reduce the permeation of the composite components. Under the condition of a certain porosity, the laminates with small, stripe voids had a higher permeation rate than the laminates with large, circular voids.

PHARMACEUTICAL WORLD OF PERMEATION ENHANCERS

The drugs with poor solubility results in delayed absorption which consequently affects the bioavailability. There are many drugs which are having good therapeutic value but not used commercially because of this reason. The permeation enhancers are therefore being utilized to counter this problem. There are many such synthetic and natural materials which have the ability to enhance the drug permeation rate. The essential oils, alcohols, terpenes, azoles and many other chemical derivatives have the capability to be used for permeation enhancer. The present review work suggested the role of permeation enhancer in the pharmaceutical world.

Piroxicam Percutaneous Permeation from Gels Through Membrane Models of Shed Snakeskin and Cellulose

Skin has a very important role in determining percutaneous absorption of active substance in topical administration. Study on percutaneous permeation of piroxicam from gel had been conducted using Franz Diffusion Cell with membrane model of shed snakeskin and cellulose. Piroxicam gels were made using Aqupec HV-505 base with 0; 2.5; 5; and 7.5% of DMSO as an enhancer. The results showed that the most stable gel preparation was the one with 5% DMSO (F2), so it was used for further investigation to which percutaneous permeation test. The permeation test was conducted in preparation without and with 5% DMSO (F2) in vitro through shed snakeskin and cellulose membranes. The results showed that F2 increased the permeation rate by as much as 0.0281% per minute. In comparison, the permeation rate of formulation without DMSO (F0) was 0.012% per minute. It can be concluded that DMSO can increase piroxicam penetration through shed snakeskin. Permeation study using cellulose membrane on formula F2 revealed permeation rate as much as 0.006% per minute whereas that without DMSO (F0) was 0.0112% per minute.Keywords: DMSO, cellulose membrane, percutaneous permeation, piroxicam, shed snakeskin.

EMERGING GAMUT OF CARDIOVASCULAR NANOMEDICINE: FUTURE IS BRIGHT

The aim of cardiovascular nanomedicine- CVN is to reduce off-target toxicity issues with therapeutic selectivity to the heart .The lipophilic barrier of the cellular membranes should be circumvented to deliver cargo inside the cell. Lipidbased NPs, which show low side effects and greater ability to passively accumulate at tissues with higher vascular permeability (enhanced permeation rate), have been largely used since the earlier times of cardiovascular nanomedicine-CVN. Polymeric NPs, silica NPs, carbon nanotubes, polymeric micelles, quantum dots, nanobers and nanocrystals represent other examples of nano-formulations for controlled drug delivery. NP-loaded drugs are expected to be protected from systemic degradation, show reduced toxicity and immunogenicity, possess ameliorated pharmacokinetics and increased half-life and exhibit increased bioavailability and precise bio distribution. Nanodrug formulations are expected to enhance selective delivery to the site of interest and benet from a lower clearance from the body. Nanotechnology represents a convergent discipline in which the margins separating research areas, such as chemistry, biology, physics, mathematics and engineering become blurred with the much needed emergence of integrated science as a new discipline.