Bioinspired Viscoelastic Capsules: Delivery Vehicles and Beyond

Microcapsules are often used as individually dispersed carriers of active ingredients to prolong their shelf life or to protect premature reactions with substances contained in the surrounding. This study goes beyond this application and employs microcapsules as principal building blocks of macroscopic 3D materials with well‐defined granular structures. To achieve this goal and inspired by nature, capsules are fabricated from block‐copolymer surfactants that are functionalized with catechols, a metal‐coordinating motive. These surfactants self‐assemble at the surface of emulsion drops where they are ionically cross‐linked to form viscoelastic capsules that display a low permeability even toward small encapsulants. It is demonstrated that the combination of the mechanical strength, flexibility, and stickiness of the capsules enables their additive manufacturing into macroscopic granular structures. Thereby, they open up new opportunities for 3D printing of soft, self‐healing materials composed of individual compartments that can be functionalized with different types of spatially separated reagents.     

Supercooling Water in Cylindrical Capsules

An experimental apparatus was developed to investigate the supercooling phenomenon of water inside cylindrical capsules used for a cold storage process. The coolant is a water–alcohol mixture controlled by a constant temperature bath (CTB). Temperatures varying with time are measured inside and outside the capsule. Cylinders with an internal diameter and thickness of 45 and 1.5 mm, respectively, were made from four different materials: acrylic, PVC, brass, and aluminum. The supercooling period of the water and the nucleation temperature were investigated for different coolant temperatures. The supercooling and nucleation probabilities are shown as a function of the coolant temperature for the four different materials. Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A.     

New Metal Hydrides: A Survey

We propose a survey of the studies carried out in the field of metal hydrides at the Karpenko Physicomechanical Institute for the last 15 years (1985–2000). Our attention is mainly given to the fundamental and applied aspects of the use of new highly efficient hydrogen absorbers, their structure and properties, and the application of the hydrogenation–disproportionation–desorption–recombination route in processing alloys of rare-earth metals and zirconium (materials for improved permanent magnets and hydrogen-storage materials). The results of these studies were published in more than 60 papers. The last of these directions of investigations represents the results of scientific cooperation between the Physicomechanical Institute and the School of Metallurgy and Materials, University of Birmingham, started in 1992.     

Metal Halide Perovskite Nanorods: Shape Matters

Quasi-1D metal halide perovskite nanorods (NRs) are emerging as a type of materials with remarkable optical and electronic properties. Research into this field is rapidly expanding and growing in the past several years, with significant advances in both mechanistic studies of their growth and widespread possible applications. Here, the recent advances in 1D metal halide perovskite nanocrystals (NCs) are reviewed, with a particular emphasis on NRs. At first, the crystal structures of perovskites are elaborated, which is followed by a review of the major synthetic approaches toward perovskite NRs, such as wet-chemical synthesis, substrate-assisted growth, and anion exchange reactions, and discussion of the growth mechanisms associated with each synthetic method. Then, thermal and aqueous stability and the linear polarized luminescence of perovskite NRs are considered, followed by highlighting their applications in solar cells, light-emitting diodes, photodetectors/phototransistors, and lasers. Finally, challenges and future opportunities in this rapidly developing research area are summarized.     

Colorimetric Determination of Piroxicam in Capsules

A simple colorimetric procedure to quantify piroxicam in capsules has been developed. The method is based on the reaction between piroxicam and 4-aminoantipyrine producing an orange color which can be measured at 490 nm. The method is accurate and precise with a percent relative standard deviation of 0.8 based on 5 readings. The results compared very well with the results obtained using the HPLC procedure. The extraction of piroxicam from the capsule powder is very simple which requires only 4 minutes, versus a 30 minute mechanical shaking recommended by the USP-NF. The results of the decomposed samples were similar to the results obtained using the HPLC method.     

Metal induced crystallization: Gold versus aluminium

In this work metal induced crystallization was studied using aluminium and gold deposited over 150 nm amorphous silicon films grown by LPCVD. Aluminium and gold layers with thickness between 1 and 5 nm were deposited on the silicon films and after that, the samples were annealed at 500^∘C from 5 up to 30 h. When the crystallization is induced through a gold layer, the Si crystalline fraction is higher than when using aluminium. For samples crystallized for 30 h at 500^∘C with 2 nm of metal a crystalline fraction of 57.5% was achieved using gold and only 38.7% when using aluminium.     

Advanced Subcompartmentalized Microreactors: Polymer Hydrogel Carriers Encapsulating Polymer Capsules and Liposomes

The design of compartmentalized carriers for advanced drug delivery systems or artificial cells and organelles is of interest for biomedical applications. Herein, a polymer carrier microreactor that contains two different classes of subcompartments, multilayered polymer capsules and liposomes, is presented. 50 nm‐diameter liposomes and 300 nm‐diameter polymer capsules are encapsulated into a larger polymer carrier capsule, demonstrating control over the spatial positioning of the subcompartments, which are either ‘membrane‐associated’ or 'free‐floating’ in the aqueous interior. Selective and spatially dependent degradation of the 300 nm‐diameter subcompartments (without destroying the structural integrity of the enzyme‐loaded liposomes) is also shown, by performing an encapsulated enzymatic reaction using the liposomal subcompartments. These findings cover several important aspects toward the development of engineered compartmentalized carrier vessels for the creation of artificial cell mimics or advanced therapeutic delivery systems.     

Metal materials biodegradation: a chronoamperometric study

The aim of this work is to illustrate the use of a reliable electrochemical technique — chronoamperometry — for the study of the biodegradation process that metal alloys suffer in the human body. The designedin vitro experiments, simulating in a short period the situationin vivo, can be used to quantify the materials corrosion resistance. Data on the amount of released materials can also be obtained which is valuable information for research on biocompatibility.     

Disintegrating Agents in Hard Gelatin Capsules. Part II: Swelling Efficiency

Abstract

The wicking and swelling properties of pure disintegrants were investigated from plugs prepared under conditions similar to those used in encapsulation of powder mixtures into hard gelatin capsules. Pure AcDiSol exhibited the greatest wicking and swelling action followed by Primojel, Polyplasdone-XL 10 and corn starch. The swelling properties of pure disintegrants correlated best with the swelling of formulation mixtures and the efficiency of these materials in enhancing the dissolution of hydrochlorothiazide. A change in the penetrating liquid from dilute acid to water altered the liquid uptake and swelling of AcDiSol and Primojel but not those of Polyplasdone-XL 10 and corn starch. The extent of swelling per unit volume of liquid absorbed, defined as the swelling efficiency, varied with time and type of disintegrant. The swelling efficiencies of pure AcDiSol and corn starch were unaffected by the nature of the penetrating liquid while Primojel and Polyplasdone-XL 10 exhibited greater efficiencies in water than in dilute acid. All disintegrants lost part of their efficiency when incorporated in capsule formulations, especially in very hydrophilic matrices. The rate of wicking action could be a limiting step in the rate and extent of swelling of a disintegrant and hence hinder its efficacy in hard gelatin capsules.     

金属粉末注射成形的原理与发展趋势

金属粉末注射成形技术是一种高效的近净成形技术,适用于生产小型的、具有复杂形状的零部件。本文综述了金属粉末注射成形技术的发展历程;概述了金属粉末注射成形原理,包括粉末和粘结剂的选择、混炼,注射成形及后续的脱脂、烧结;并介绍了金属粉末微注射成形技术的技术特点、注射工艺和微注射成形的应用;分析了金属粉末注射成形技术的局限性;展望了金属粉末注射成形技术的发展趋势,认为预制复合粉末有助于解决混炼和注射造成的成分不均匀,减小烧结过程由于收缩不均匀导致的制件变形,且应开发新的粘结剂和脱脂工艺以减少脱脂后其在材料中的残留和碳化,开发少粘结剂注射成形工艺。     

美国对药用胶囊的严格监管

美国一颗胶囊的监管没有哪家胶囊企业希望自己的名字出现在美国食品和药物管理局(FDA)的警告信中。对于全球制药业来说,1931年一项不起眼的发明,有着特别的价值。那年在美国,在一家名为帕克—戴维斯(Parke-Davis)的公司一度也是全球最大的制药企业,工程师阿     

Cell-Like Capsules with “Smart” Compartments

Eukaryotic cells have inner compartments (organelles), each with distinct properties and functions. One mimic of this architecture, based on biopolymers, is the multicompartment capsule (MCC). Here, MCCs in which the inner compartments are chemically unique and “smart,” i.e., responsive to distinct stimuli in an orthogonal manner are created. Specifically, one compartment alone is induced to degrade when the MCC is contacted with an enzyme while other compartments remain unaffected. Similarly, just one compartment gets degraded upon contact with reactive oxygen species generated from hydrogen peroxide (H₂O₂). And thirdly, one compartment alone is degraded by an external, physical stimulus, namely, by irradiating the MCC with ultraviolet (UV) light. All these specific responses are achieved without resorting to complicated chemistry to create the compartments: the multivalent cation used to crosslink the biopolymer alginate (Alg) is simply altered. Compartments of Alg crosslinked by Ca²⁺ are shown to be sensitive to enzymes (alginate lyases) but not to H₂O₂ or UV, whereas the reverse is the case with Alg/Fe³⁺ compartments. These results imply the ability to selectively burst open a compartment in an MCC “on-demand” (i.e., as and when needed) and using biologically relevant stimuli. The results are then extended to a sequential degradation, where compartments in an MCC are degraded one after another, leaving behind an empty MCC lumen. Collectively, this work advances the MCC as a platform that not only emulates key features of cellular architecture, but can also begin to capture rudimentary cell-like behaviors.     

Specific Capacitance and Cyclic Stability of Graphene Based Metal/Metal Oxide Nanocomposites:A Review

Graphene has become a worldwide admired material among researchers and scientists equally due to its unique richness in mechanical strength,electrical conductivity,optical and thermal properties.Researchers have explored that the composite materials based on graphene and metal/metal oxide nanostructures possess excellent potential for energy storage technologies.In particular,supercapacitors based on such composite materials have engrossed the extreme interest of researchers for its rapid charging/discharging time,safe operation and longer cyclic constancy.Till now,several fabrication techniques for composite materials and their energy storage applications have been explored.Here,specially,we have concentrated on the hottest research progress for the fabrication of graphene oxide and metal/metal oxide nanocomposites.We also emphasized on the characteristics and properties of supercapacitors fabricated using these composite materials.Moreover,our study is focused on the specific capacitance and cyclic stability of various composites to haul out the most efficient material for supercapacitor applications.     

Dissolution Test for Silymarin Tablets and Capsules

Silybine (SBN), isosilybine (ISBN), silycristine (SCN), silydianine (SDN), and taxifoline (TXF) are the main active flavonoids commonly found in the dried fruits of Silybum marianum, Gaertner (Compositae). Concentrations of these compounds, except TXF, are usually expressed together as silymarin content. This paper describes a simple dissolution test developed to estimate silymarin (Sl) in pharmaceutical formulations. Five commercial products were tested using this new method (including tablets, sugar tablets, and capsules): two from Argentina, one from Brazil, one from Spain, and one from Italy. Results demonstrated that, provided the dosage form disintegrates, amounts dissolved range from 50 to 90% of the labeled value. Products were analyzed by high performance liquid chromatography (HPLC) and UV spectrophotometry.     

云南白药胶囊药品的交互包装设计

目的为了提升云南白药胶囊产品有效信息的传达和使用安全性,为我国传统药品包装设计研究提供新的思路和方法。方法采用问卷调查、眼动实验和行为实验,分析评价云南白药胶囊现有的包装设计,并对其进行针对性的改进。结果眼动热点图表明,外包装的正反面信息不能得到有效传达;问卷调查分析表明,外包装的药品规格、用量、禁忌等信息关注频率与重视程度严重不对等;行为实验说明保险子不方便拿取。结论得出了消费者购买可能性与眼动指标注视次数的回归方程式:Y=3.057+0.018X1,并将其应用于对云南白药胶囊的改进设计中,采用白色和绿色为主体色,对背面信息进行色彩的有效分区呈现,实现了信息的有效传达;内包装采用与外包装卡扣在一起的结构,防止儿童误食。     

Bioavailability of Eight Brands of Ampicillin Capsules

Abstract

An in vivo absorption study was performed in a crossover fashion on 6 healthy volunteers (4 males and 2 females) to compare the bioavailability of 8 brands of ampicillin capsules. Absorption was assessed by a urinary excretion method in which the drug was assayed chemically. Statistical analysis of the results was carried out to evaluate the significance of differences between brands and between subjects. Results of the analysis of variance indicated no significant differences between the tested brands of ampicillin capsules. However, significant differences between brand A and brand B were found on using the student t-test. A significant intersubject variation was also found between the volunteers participated in the present study.