Nanoparticles for Drug Delivery: Review of the Formulation and Process Difficulties Illustrated by the Emulsion-Diffusion Process

2006 ◽  
Vol 6 (9) ◽  
pp. 2664-2681 ◽  
Author(s):  
D. Moinard-Checot ◽  
Y. Chevalier ◽  
S. Briançon ◽  
H. Fessi ◽  
S. Guinebretière
Keyword(s):  
Drug Delivery ◽  
Diffusion Process ◽  
Process Development ◽  
Colloidal Suspensions ◽  
Polymeric Membrane ◽  
Physical Mechanisms ◽  
Pharmaceutical Application ◽  
Simple Scaling ◽  
Soft Particles

The elaboration of nanoparticles aqueous suspensions aimed at the drug delivery and related process development appear as difficult tasks, due to specificities related to the nanometric size. Such small sizes are required for specific applications in pharmacy. The switch of micrometric to nanometric field represents an actual challenge and cannot be considered as a simple scaling-down of chemical engineers. Ideas and concepts developed first in nanosciences have been adapted to the pharmaceutical application in drug delivery. In spite of drastic constraints due to pharmaceutical application, some parameters allow the control. A brief and not exhaustive review of the state-of-the-art on polymer particles used in the drug delivery field is presented. Attention was more particularly paid on preparation processes and their constraints by describing advantages and drawbacks of each process. The adaptation to the pharmaceutical field, the difficulties and pitfalls which are shared, with most research works in nanoscience, are illustrated thanks to our own results on nanocapsules obtained by "emulsion-diffusion" process presented as a case-study. Thanks to these results, we illustrate the peculiar features and difficulties encountered regarding nanocapsules preparation and characterization. Indeed, such a process allows to prepare nanocapsules of few hundreds nanometers diameter having an oil core surrounded by a polymeric membrane. The characterization of such soft particles colloidal suspensions is often difficult and involves heavy investigation techniques in order to highlight physical mechanisms leading to the nanocapsule properties. This is a key step regarding the final properties as a drug delivery system.

Process development and material characterization of Cu-Cu thermo-compression bonding (TCB) for high-conductivity electrical interconnects.

2016 ◽  
Vol 2016 (1) ◽  
pp. 000203-000208 ◽  
Author(s):  
Adeel Bajwa ◽  
Niteesh Marathe ◽  
SivaChandra Jangam ◽  
Saptadeep Pal ◽  
Ping-Yu Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Parameter Optimization ◽  
Electrical Resistance ◽  
Material Characterization ◽  
Process Development ◽  
Intermetallic Formation ◽  
Physical Mechanisms ◽  
Electrical Interconnects ◽  
Metal Metal

Abstract In this work, we focus on metal-metal Thermo-Compression Bonding (TCB) for realizing assembly of dielets to a silicon interconnect fabric (IF). The popular metal choices include bare Cu, Cu plated with Au and Au. Our approach simplifies the metallurgies used in classic chip-to-package assemblies by avoiding the use of solder and the concomitant issues of intermetallic formation such as electrical resistance and brittleness. In this paper, we address TCB parameter optimization and material characteristics of these metal-metal TCB joints. The roles of two physical mechanisms on Cu-Cu interface voiding i.e. surface roughness prior to TCB, oxide presence at bonding interface are evaluated in detail.

Characterization of Unfilled Tungsten Plugs on a 0.35μm CMOS Multilevel Metallization Process

1996 ◽  
Author(s):  
H. Sur ◽  
S. Bothra ◽  
Y. Strunk ◽  
J. Hahn
Keyword(s):  
Process Development ◽  
Process Integration ◽  
Wafer Level ◽  
Electrical Failure ◽  
Analysis Techniques ◽  
Integration Approach ◽  
Intermetal Dielectric ◽  
Metallization Process ◽  
Section Analysis

Abstract An investigation into metallization/interconnect failures during the process development phase of an advanced 0.35μm CMOS ASIC process is presented. The corresponding electrical failure signature was electrical shorting on SRAM test arrays and subsequently functional/Iddq failures on product-like test vehicles. Advanced wafer-level failure analysis techniques and equipment were used to isolate and identify the leakage source as shorting of metal lines due to tungsten (W) residue which was originating from unfilled vias. Further cross-section analysis revealed that the failing vias were all exposed to the intermetal dielectric spin-on glass (SOG) material used for filling the narrow spaces between metal lines. The outgassing of the SOG in the exposed regions of the via prior to and during the tungsten plug deposition is believed to be the cause of the unfilled vias. This analysis facilitated further process development in eliminating the failure mechanism and since then no failures of this nature have been observed. The process integration approach used to eliminate the failure is discussed.

Biopolymers with Medical Applications Optimized method for obtaining chitosan-based delivery systems

2018 ◽  
Vol 69 (7) ◽  
pp. 1756-1759 ◽  
Author(s):  
Luminita Confederat ◽  
Iuliana Motrescu ◽  
Sandra Constantin ◽  
Florentina Lupascu ◽  
Lenuta Profire
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Average Diameter ◽  
Delivery Systems ◽  
Cross Linking ◽  
Low Molecular Weight ◽  
Polymeric Systems ◽  
Chitosan Microparticles ◽  
Degree Of Swelling

The aim of this study was to optimize the method used for obtaining microparticles based on chitosan � a biocompatible, biodegradable, and nontoxic polymer, and to characterize the developed systems. Chitosan microparticles, as drug delivery systems were obtained by inotropic gelation method using pentasodiumtripolyphosphate (TPP) as cross-linking agent. Chitosan with low molecular weight (CSLMW) in concentration which ranged between 0.5 and 5 %, was used while the concentration of cross-linking agent ranged between 1 and 5%. The characterization of the microparticles in terms of shape, uniformity and adhesion was performed in solution and dried state. The size of the microparticles and the degree of swelling were also determined. The structure and the morphology of the developed polymeric systems were analyzed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM).The average diameter of the chitosan microparticles was around 522 �m. The most stable microparticles were obtained using CSLMW 1% and TPP 2% or CSLMW 0.75%and TPP 1%. The micropaticles were spherical, uniform and without flattening. Using CSLMW in concentration of 0.5 % poorly cross-linked and crushed microparticles have been obtained at all TPP concentrations. By optimization of the method, stable chitosan-based micropaticles were obtained which will be used to develop controlled release systems for drug delivery.

Hydrogel-clay Nanocomposites as Carriers for Controlled Release

2020 ◽  
Vol 27 (6) ◽  
pp. 919-954 ◽  
Author(s):  
Raluca Ianchis ◽  
Claudia Mihaela Ninciuleanu ◽  
Ioana Catalina Gifu ◽  
Elvira Alexandrescu ◽  
Cristina Lavinia Nistor ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Hybrid Materials ◽  
Pharmaceutical Formulations ◽  
Tree Of Life ◽  
Present Review ◽  
Clay Nanocomposites ◽  
Delivery Platform ◽  
Complex Hybrid

The present review aims to summarize the research efforts undertaken in the last few years in the development and testing of hydrogel-clay nanocomposites proposed as carriers for controlled release of diverse drugs. Their advantages, disadvantages and different compositions of polymers/biopolymers with diverse types of clays, as well as their interactions are discussed. Illustrative examples of studies regarding hydrogel-clay nanocomposites are detailed in order to underline the progressive researches on hydrogel-clay-drug pharmaceutical formulations able to respond to a series of demands for the most diverse applications. Brief descriptions of the different techniques used for the characterization of the obtained complex hybrid materials such as: swelling, TGA, DSC, FTIR, XRD, mechanical, SEM, TEM and biology tests, are also included. Enlightened by the presented data, we can suppose that hydrogel-clay nanocomposites will still be a challenging subject of global assiduous researches. We can dare to dream to an efficient drug delivery platform for the treatment of multiple affection concomitantly, these being undoubtedly like ”a tree of life” bearing different kinds of fruits and leaves proper for human healing.

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