Novel manufacturing process of hollow polymer microspheres

Schmidt, Wolfgang; Roessling, Georg

doi:10.1016/j.ces.2006.03.021

Cited by 28 publications

(18 citation statements)

References 24 publications

(23 reference statements)

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“…They were first developed by Paul and Jones in 1953 and were prepared in silicone. 11 These microspheres have been commercially available for more than 30 years. Microspheres with an inorganic shell are used as fillers for cement and latex dispersions and for insulation.…”

Section: Introductionmentioning

confidence: 99%

Compressible magnetorheological fluids

Fuchs

Rashid

Liu

et al. 2009

J of Applied Polymer Sci

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A novel compressible magnetorheological fluid (CMRF) has been synthesized with additives that provide compressibility to the fluid. This CMRF has been designed to provide an elastic component to a magnetorheological fluid (MRF) that can be used as a springless damper. CMRF provides controllable compressibility to the MRF. The controllability of the fluid is achieved by the use of magnetic particles and an external magnetic field, and the fluid is made compressible by the addition of suspended compressible polymer particles. The compressibility of the fluid has been characterized with forcedisplacement measurements. This CMRF has controllable off-state viscosity and high shear yield stress. The incorporation of polymeric particles into the MRF also decreases the settling of iron particles and improves the redispersion of the fluid. To make the fluid more redispersible, the surface of the iron particles is coated with a high-temperature fluorinated polymer.

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Section: Introductionmentioning

confidence: 99%

Compressible magnetorheological fluids

Fuchs

Rashid

Liu

et al. 2009

J of Applied Polymer Sci

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“…When evaporation of solvents was complete, the hollow microspheres formed were separated by filtration, washed with n-hexane and dried in an air oven at 50 ºC for 12 hours before being stored in a desiccator. Schmidt and Roessling (2006) developed a novel manufacturing process of gas-filled, hollow, poly-butyl-2-cyanoacrylate (PBCA) microspheres in an aqueous phase. A novel two-step manufacturing process was developed to synthesize gas-filled hollow microspheres.…”

Section: Methods Of Preparation Of Hollow Microspheresmentioning

confidence: 99%

“…The diagrammatic representation of mechanism of formation of floating microspheres is given in the Figure 2. The inner porous FIGURE 1 -Scheme of the two-step process for the synthesis of gas-filled hollow microspheres (Schmidt, Roessling, 2006). structure was attributed to the inward diffusion of water, which resulted in the solidification of the polymer and the formation of several smaller pockets of dichloromethane rich entrapments which diffused out together with ethanol.…”

Section: Mechanism Of Formation Of Hollow Microspheresmentioning

confidence: 99%

Floating microspheres: a review

Mukund

Kantilal

Sudhakar

2012

Braz. J. Pharm. Sci.

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Gastric emptying is a complex process, one that is highly variable and that makes in vivo performance of drug delivery systems uncertain. A controlled drug delivery system with prolonged residence time in the stomach can be of great practical importance for drugs with an absorption window in the upper small intestine. The main limitations are attributed to the inter-and intra-subject variability of gastrointestinal (GI) transit time and to the non-uniformity of drug absorption throughout the alimentary canal. Floating or hydrodynamically controlled drug delivery systems are useful in such applications. Various gastroretentive dosage forms are available, including tablets, capsules, pills, laminated films, floating microspheres, granules and powders. Floating microspheres have been gaining attention due to the uniform distribution of these multiple-unit dosage forms in the stomach, which results in more reproducible drug absorption and reduced risk of local irritation. Such systems have more advantages over the single-unit dosage forms. The present review briefly addresses the physiology of the gastric emptying process with respect to floating drug delivery systems. The purpose of this review is to bring together the recent literature with respect to the method of preparation, and various parameters affecting the performance and characterization of floating microspheres.Uniterms: Floating microspheres. Emulsion solvent diffusion-evaporation method. Drug delivery system. Release modifiers.O esvaziamento gástrico é um processo complexo, com elevada variabilidade e responsável pela incerteza do desempenho dos medicamentos in vivo. Dessa forma, os sistemas de liberação modificada de fármacos, com tempo de residência prolongado no estômago, em especial, considerando aqueles fármacos com janela de absorção na porção superior do intestino delgado, apresentam fundamental importância. As principais limitações relativas à absorção do fármaco são, no geral, atribuídas à variabilidade inter e intra-paciente do tempo de trânsito gastro-intestinal (GI) e da não-uniformidade da absorção do fármaco na extensão do canal alimentar. Assim, justifica-se a utilização dos sistemas flutuantes ou hidrodinâmicos de liberação de fármacos. Vários medicamentos gastrorretentivos estão disponibilizados no mercado e incluem comprimidos, cápsulas, pílulas, filmes laminados, microesferas flutuantes, grânulos e pós. As microesferas flutuantes apresentam maior destaque em função da distribuição granulométrica uniforme dessas formulações de dose múltipla. Como resultado, a absorção do fármaco apresenta maior reprodutibilidade e os riscos associados à irritação local são reduzidos. Tais sistemas apresentam maior vantagem quando comparado às formulações de dose única. A presente revisão tem como objetivo apresentar as publicações recentes referentes aos métodos de preparação, os vários parâmetros que afetam o desempenho e a caracterização das microesferas flutuantes. Além disso, o presente trabalho aborda a fisiologia do processo de esvaziamento gást...

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“…It may be inferred that the agitation speed over the study range is not able to break up the bulk of the polymer into finer droplets 25,26 .…”

Section: Stirring Ratementioning

confidence: 99%

“…At lower emulsifier concentrations, droplets are more likely to collide and fused to form larger globules; it is insufficient to shield the entire droplet surface. At higher concentration of emulsifier, it reduces the encapsulation efficiency 25 . Hence, the optimum concentration of the emulsifier should be identified 33 .…”

Section: Emulsifier Concentrationmentioning

confidence: 99%

Microballoons: An Advance Avenue for Gastroretentive Drug Delivery System- A Review

Kumar

Kamboj

Chandra

et al. 2016

PBJ

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The purpose of writing this review on microballoons is to accumulate the recent literature with a special focus on the novel technological advancements in floating drug delivery system to achieve gastric retention. Microballoons (Hollow microsphere) promises to be a potential approach for gastric retention. Microballoons drug-delivery systems are based on noneffervescent system containing empty particles of spherical shape without core ideally having a size less than 200 micrometer. Microballoons drug delivery systems have shown to be of better significance in controlling release rate for drugs having site specific absorption. The floating microballoons showed gastroretentive controlled release delivery with efficient means of enhancing the bioavailability and promises to be a potential approach for gastric retention.Optimized hollow microspheres will find the central place in novel drug delivery, particularly in safe, targeted and effective in vivo delivery promises to be a potential approach for gastric retention. They are gastroretentive drug-delivery systems, which provide controlled release properties. The advantages, limitation, methods of preparation of hollow microsphere, applications, polymers used in hollow microspheres, characterizations of microballoons and formulation aspects with various evaluation techniques and marketed products are covered in detail.

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Novel manufacturing process of hollow polymer microspheres

Cited by 28 publications

References 24 publications

Compressible magnetorheological fluids

Compressible magnetorheological fluids

Floating microspheres: a review

Microballoons: An Advance Avenue for Gastroretentive Drug Delivery System- A Review

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