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2021 ◽  
Author(s):  
Yayi Yi

Summary Background The Coronavirus Disease 2019 (COVID-19) has swept the whole world with high mortality. Since aerosol transmission is the main route of transmission, wearing a mask serves as a crucial preventive measure. An important parameter to evaluate the performance of a mask is the bacteria filtration efficiency (BFE). Aerosol mean particle size (MPS) and positive quality control value are two key indexes of BFE system. Aim To study the major influence factors of the mean particle size of bacterial aerosols and positive quality control value of BFE system. Method and Results In this study, we investigated the influence of Anderson sampler, spray flow, medium thickness, and peristaltic pump flow on the MPS of bacterial aerosols and positive quality control value of BFE system, respectively. The results show that the machining accuracy of Anderson sampler has great influence on aerosol MPS and positive quality control value. With the increase of aerosol spray flow rate, the positive quality control value will increase gradually, but the effect on aerosol MPS is not a simple linear relationship. As the agar medium thickness increased, the positive quality control value and aerosol MPS increased gradually. With the increase of peristaltic pump flow, the positive quality control value increased gradually, while the aerosol MPS was basically in a downward trend. When the peristatic pump flow rate was 0.1mL/min, the spray flow rate was 7.2L/min, the agar plate thickness was 27mL, and the Anderson sampler of Beijing Mingjie was used for the experiment, the aerosol MPS and positive quality control value were both within the acceptable range and were the optimal parameters. Conclusions This study provides guidance for the manufacturers of the BFE system and improves the protective performance of masks, which is important for the human health, especially during the occurrence of viral pandemics such as "COVID-19".


Pharmaceutics ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1999
Author(s):  
Ryoka Goto ◽  
Shigehiro Yamada ◽  
Hiroko Otake ◽  
Yosuke Nakazawa ◽  
Mikako Oka ◽  
...  

We developed ophthalmic formulations based on nilvadipine (NIL) nanocrystals (NIL-NP dispersions; mean particle size: 98 nm) by using bead mill treatment and investigated whether the instillation of NIL-NP dispersions delivers NIL to the lens and prevents lens opacification in hereditary cataractous Shumiya cataract rats (SCRs). Serious corneal stimulation was not detected in either human corneal epithelial cells or rats treated with NIL-NP dispersions. The NIL was directly delivered to the lens by the instillation of NIL-NP dispersions, and NIL content in the lenses of rats instilled with NIL-NP dispersions was significantly higher than that in the ophthalmic formulations based on NIL microcrystals (NIL-MP dispersions; mean particle size: 21 µm). Moreover, the supply of NIL prevented increases in Ca2+ content and calpain activity in the lenses of SCRs and delayed the onset of cataracts. In addition, the anti-cataract effect in the lens of rats instilled with NIL-NP dispersions was also significantly higher than that in NIL-MP dispersions. NIL-NPs could be used to prevent lens opacification.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1871
Author(s):  
Baskaran Stephen Inbaraj ◽  
Leng-Huei Hua ◽  
Bing-Huei Chen

Resveratrol, a phenolic compound possessing vital biological activities such as anti-cancer, is present abundantly in grape skin, a waste produced during the processing of grape juice. The objectives of this study were to prepare resveratrol-gold nanoparticles and a resveratrol nanoemulsion from grape skin and study their inhibition effects on pancreatic cancer cells BxPC-3. The spherical-shaped citrate gold nanoparticles (GNPs) and resveratrol-gold nanoparticles (R-GNPs) were, respectively, prepared with a surface plasmon resonance peak at 528 and 538 nm, mean particle size of 20.8 and 11.9 nm, and zeta-potential at −32.7 and −66.7 mV, by controlling an appropriate concentration of citrate/resveratrol and gold chloride as well as stirring time and temperature. The resveratrol nanoemulsion, composed of soybean oil, Tween 80, and sucrose fatty acid ester in glycerol and water, possessed a high storage stability with a mean particle size of 14.1 nm, zeta-potential of −49.7 mV, and encapsulation efficiency of 95.5%. An antiproliferation study revealed that both R-GNPs and resveratrol nanoemulsion could effectively inhibit the growth of pancreatic cancer cells BxPC-3, with the latter showing a higher inhibition effect. Western blot analysis implied that both can down-regulate expressions of cyclin A, cyclin B, CDK1, and CDK2 and up-regulate expressions of p53 and p21, accompanied by enhancing cytochrome C expression, decreasing BcL-2 expression, increasing Bax expression, and leading to the elevation of caspase-8, caspase-9, and caspase-3 activities for cell apoptosis execution. Future research is needed to study the inhibition of pancreatic tumors in vivo by R-GNPs and resveratrol nanoemulsions.


Author(s):  
Vaishak Ramesh Sagar ◽  
Samuel Lorin ◽  
Johan Göhl ◽  
Johannes Quist ◽  
Christoffer Cromvik ◽  
...  

Abstract Selective laser melting (SLM) process is a powder bed fusion additive manufacturing process that finds applications in aerospace and medical industries for its ability to produce complex geometry parts. As the raw material used is in powder form, particle size distribution (PSD) is a significant characteristic that influences the build quality in turn affecting the functionality and aesthetics aspects of the product. This paper investigates the effect of PSD on the printed geometry for 316L stainless steel powder, where three coupled in-house simulation tools based on Discrete Element Method (DEM), Computational Fluid Dynamics (CFD), and Structural Mechanics are employed. DEM is used for simulating the powder bed distribution based on the different powder PSD. The CFD is used as a virtual testbed to determine thermal parameters such as heat capacity and thermal conductivity of the powder bed viewed as a continuum. The values found as a stochastic function of the powder distribution is used to analyse the effect on the melted zone and deformation using Structural Mechanics. Results showed that mean particle size and PSD had a significant effect on the packing density, melt pool layer thickness, and the final layer thickness after deformation. Specifically, a narrow particle size distribution with smaller mean particle size and standard deviation produced solidified final layer thickness closest to nominal layer thickness. The proposed simulation approach and the results will catalyze in development of geometry assurance strategies to minimize the effect of particle size distribution on the geometric quality of the printed part.


2021 ◽  
Vol 01 ◽  
Author(s):  
Jiaojiao Zhang ◽  
Xinghua Zhao ◽  
Cuiying Ren ◽  
Yujia Kang ◽  
Shi Ding ◽  
...  

Background: Allergic Rhinitis (AR) is a kind of systemic inflammatory response caused by a variety of allergic sources, which is mediated by immunoglobulin IgE. The major clinical manifestations including nasal congestion, itchy, runny nose, sneezing and so on. It affects the patient's normal life seriously. Using the nasal spray is the main way to treat and relieve symptoms allergic rhinitis. Triamcinolone acetonide was the first choice for treatment of allergic rhinitis medicine[1], because it has a very good treatment effect and less adverse reactions, but the solubility is poor[2], so we prepared it into supramolecular inclusion to increase the solubility[3], then promote the absorption of triamcinolone in the nasal cavity, and improving the bioavailability of the drug. Objective: The aim of the study was to improve triamcinolone acetonide solubility, So we prepared it into supramolecular inclusion to promote the absorption of triamcinolone in the nasal cavity, and improving the bioavailability of the drug. Methods: The supramolecular inclusion solids of triamcinolone cyclodextrin were prepared by freeze-drying method[4], and the preparation conditions of triamcinolone acetonide- hydroxypropyl -β -cyclodextrin supramolecular inclusion was as follows: the feed ratio of host to guest was 12:1, the inclusion time was 2h, and the temperature was 50℃. Results: The supramolecular inclusion complex was characterized by differential scanning calorimetry and scanning electron microscopy to verify that the supramolecular inclusion complex had been formed[5]. The results of infrared spectrum showed that triamcinolone acetonide molecules had entered the cavity of the cyclodextrin to form the supramolecular inclusion complex with the cyclodextrin[6], and phase solubility experiment showed that HP-β-CD had solubilization effect on triamcinolone acetonide. The mean particle size measured values of triamcinolone-HP-β-CD supramolecular inclusion compound is 13.61±1.03nm, much less than triamcinolone acetonide nasal spray, and the triamcinolone-HP-β-CD supramolecular inclusion nasal spray is 1.09±0.01, whith is smaller than triamcinolone acetonidewhich, too. This means triamcinolone-HP-β-CD supramolecular inclusion nasal spray has more uniform contact with the nasal cavity, which is better for absorption greatly improved its bioavailability and provided a new therapeutic agent for patients with allergic rhinitis. Discussion: In this study, triamcinolone acetonid-hydroxypropyl-β-cyclodextrin supramolecular inclusion complex was successfully synthesized, and then triamcinolone acetonide cyclodextrin nasal spray was successfully developed. Data shows that the mean particle size measured values and the ellipticity of triamcinolone-HP-β-CD supramolecular inclusion nasal spray are much less than triamcinolone acetonide nasal spray, this means triamcinolone-HP-β-CD supramolecular inclusion nasal spray has more uniform contact with the nasal cavity, so, triamcinolone-HP-β-CD supramolecular inclusion nasal spray is better for absorption, can greatly improved its bioavailability, also, provided a new therapeutic agent for patients with allergic rhinitis. In addition, the experimental results of nasal spray on guinea pig AR model showed that triamcinolone-HP-β-CD supramolecular inclusion nasal spray nasal spray had a significant inhibitory effect on guinea pig allergic rhinitis, and the effect was most obvious in the medium-dose and high-dose groups.


2021 ◽  
pp. 1-62
Author(s):  
Mei Han ◽  
Scott A. Braun

AbstractThis study addresses the global distribution of precipitation mean particle size using data from the Global Precipitation Measurement (GPM) mission. The mass-weighted mean diameter, Dm, is a characteristic parameter of the precipitation particle size distribution (PSD), estimated from the GPM Combined Radar-Radiometer Algorithm (CORRA) using data from GPM’s dual-frequency precipitation radar and microwave imager. We examine Dm in individual precipitation systems in different climate regimes and investigate a six-year (2014-2020) global climatology within 70° N/S.The vertical structure of Dm is demonstrated with cases of deep convection, frontal rain and snow, and stratocumulus light rain. The Dm values, detectable by GPM, range from ~0.7 mm in stratocumulus precipitation to >3.5 mm in the ice layers of intense convection. Within the constraint of the 12-dBZ detectability threshold, the smallest annual mean Dm (~ 0.8 mm) are found in the eastern oceans, and the largest values (~ 2 mm) occur above the melting levels in convection over land in summer. The standard deviation of the annual mean is generally < 0.45 mm below 6 km.Climate regimes are characterized with Dm annual/seasonal variations, its convective/stratiform components, and vertical variabilities (2-10 km). The US Central Plains and Argentina are associated with the largest Dm in a deep layer. Tropical Africa has larger Dm and standard deviation than Amazon. Large convective Dm occurs at high latitudes of Eurasia and North America in summer; the southern hemisphere high latitudes have shallower systems with smaller Dm. Oceanic storm tracks in both hemispheres have relatively large Dm, particularly for convective Dm in winter. Relatively small Dm occurs over tropical oceans, including ITCZ, requiring further investigation.


Author(s):  
SANDIP MALI ◽  
NISHANT OZA

Objective: The aim of the present study was to optimize long-acting injectable (LAI) microspheres of Paliperidone palmitate (PP) for treatment of schizophrenia using face-centered central composite design (FC-CCD). Methods: In this study, poly lactic-co-glycolic acid (PLGA) based LAI microspheres of paliperidone palmitate (PP) were formulated by using FC-CCD. LAI microspheres were developed by using oil in water (O/W) emulsion solvent evaporation technique. On the basis of preliminary trials, FC-CCD was employed to check effect of independent variables such as drug polymer ratio (X1), homogenization speed (X2) and rate of addition (X3). While mean particle size (Y1), drug loading (Y2), entrapment efficiency (Y3), burst release (Y4), and drug release on day 60 (Y5) were considered as dependent variables and statistically evaluation performed by using design expert 12 software. Morphology of prepared microspheres was studied by using the scanning electron microscopy (SEM) technique, while particle size was analyzed by laser diffraction technique. In vitro drug release studies were performed using a controlled temperature shaking water bath apparatus. Fourier transforms infrared spectroscopy (FTIR) and differential scanning calorimetric (DSC) study were performed to analyze any changes in crystal behavior or to detect any chemical bonding between ingredients. 13C NMR and 1H NMR techniques were used to analyze end-capping and monomer ratio in developed microspheres. Results: The factorial batches mean particle size was found to be 38 µm to 104 µm and drug loading were found between 27.2 % to 47.2%. Mathematical modelling of drug release kinetics revealed that near zero-order drug release of checkpoint formulations. Endcap analysis and molar ratio of formulated microspheres were found to be ester end cap and ~75:25, respectively. Morphologically all the prepared samples were found to be spherical in shape and smooth surface. FTIR data showed no significant interactions occurred between drug and excipients. The actual responses of checkpoint formulations were observed within 5% variation of predicted values. Conclusion: The prepared microspheres showed promising results of morphology, particle size, drug loading, entrapment efficiency, burst release and drug release on day 60. The successful predictive designs models were achieved from employed FC-CCD.


Author(s):  
Ashish Y. Pawar ◽  
Khanderao R. Jadhav ◽  
Komal D. Ahire ◽  
Tushar P. Mahajan

The aim of the present work was to formulate and evaluate Miconazole nitrate (MN) polymeric nanoparticles (NPs) for systemic delivery of the active ingredient after topical administration. The Solvent evaporation approach was used to make nanoparticles for topical delivery of MN. Particle size, entrapment efficiency and SEM were all measured in MN-SLN. A consistent size distribution (PI 0.300) was used to generate aqueous NPs dispersions with a mean particle size less than 250 nm. After 3 months of storage, the produced semi-solid systems had a mean particle size of less than 250 nm and a PI of less than 0.500. The F5 formulation was been chosen as the model formulation from among the nine nanoparticle formulations developed (F1 to F9). The reason for this was that, according to the ICH stability guidelines, formulation F5 was judged to be optimal and stable. The F5 formulations of miconazole nanoparticles shows the highest entrapment efficiency (93.28%) and drug loading (86.64%). In conclusion, there are two major advantages of using miconazole nanoparticle drug delivery systems. i.e., they are topical preparations that assemble in the hair follicles and wrinkles to produce a systemic and local action. It is possible that nanoparticles will be the most effective treatment for fungal skin infections.


2021 ◽  
Author(s):  
Parisa Soraya Asa ◽  
Shahla Mirzaeei

Background: Ciprofloxacin (CIP) is a broad-spectrum antibiotic, used to treat various bacterial infections. Administration of conventional oral dosage forms of CIP is associated with multiple challenges such as short residence time of the drug in the gastrointestinal tract which could reduce bioavailability and effectiveness of the drug. This study aimed to design and develop novel floating microspheres for the sustained release of CIP in the stomach over 24 hours after oral administration, besides evaluating the effect of different variables on the characteristics of developed microspheres. Methods: Microspheres were developed by the solvent-evaporation method utilizing cellulose acetate and polyvinyl alcohol, then characterized for physicochemical properties including bulk density, buoyancy, and entrapment efficacy. The drug-excipient compatibility was evaluated by Fourier-transform infrared spectroscopy and the Scanning electron microscopy was used to observe the morphology of microspheres. The effects of the drug to polymer ratio, polymer concentration, and the pace of stirring through the preparation process, on the size and release rate were also evaluated. Results: Morphology analysis indicated round-shape microspheres with a mean particle size between 66-344 µm. The polydispersity index of prepared formulations was determined to be in the range of 0.129 to 0.230. It was observed that at higher polymer concentrations the drug release rate from microspheres decreased while the mean particle size increased. Increasing the drug to polymer ratio and decreasing the stirring speed increased the mean particle size. All formulations showed more than 70% cumulative drug release in the prolonged period of 24 h while remaining buoyant in the meantime. The formulations followed Higuchi and Korsmeyer-Peppas kinetics and release the drug by diffusion mechanism. Conclusions: Based on the results obtained from in vitro release study besides floating properties the prepared microspheres could be considered suitable for enhanced sustained-release of CIP following the oral administration.


Author(s):  
MD AAMER QUAZI ◽  
NAZIA KHANAM

Objective: Innovative enhancement of therapeutic window of Metformin hydrochloride (MFH) and bioavailability through mucoadhesive microspheres by polymeric inculcation of hydroxypropyl methylcellulose K4M grade (HPMC K4M), hydroxypropyl methylcellulose K100M grade (HPMC K100M) and Kollidon SR grade (KS). Methods: Controlled release system was developed by incorporating semi-synthetic and synthetic polymers by modified solvent evaporation technique. Fabrication of mucoadhesive microspheres was designed by the implementation of experimental designs to obtain most optimum concentration of selected factors. The method was optimized by Box Behnken design (BBD) with selected factors as concentrations of semi-synthetic and synthetic polymer with stirring speed influence for the obtained responses that were mean particle size (Y1) entrapment efficiency of drug (Y2) and percent mucoadhesion (Y3). Microspheres were characterized for particle size, entrapment efficiency of drug, ex-vivo mucoadhesion study, in vitro study, Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD) detection and H1 Nuclear magnetic resonance (NMR) quantification for optimized formulation. Results: Implementation of response surface method software for BBD yielded stable microspheres with mean particle size 274 µm, entrapment efficiency of drug 85.07% and percent mucoadhesion 67.03% for optimized formulation F5. Conclusion: Bridging of MFH with the highly innovative combination of semi-synthetic and synthetic polymers yielded stable, cost-effective microspheres with improved bioavailability with controlled-release effect as till date no literature is available that provide information with selected polymeric combination and analytical characterization.


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