This document summarizes research on the effect of polymeric nanoparticles on the stability of a biomimetic lung surfactant model. The research aims to develop a biomimetic lung surfactant model, analyze how different polymeric nanoparticles affect its stability, and understand nanoparticle localization. Results show that gelatin nanoparticles had little effect on model stability but decreased lipid domain size. Future work will test other nanoparticle types and fluorescence imaging to study localization.
Nanomaterials Article_Characterization of Hybrid Epoxy NanocompositesShelly Simcha
This document summarizes research on using different surface treatments of multi-walled carbon nanotubes (MWCNT) to improve the thermo-mechanical properties of epoxy nanocomposites. It reviews literature on MWCNT surface treatments including covalent methods like oxidation and non-covalent methods like surfactant adsorption and titania coating. Test results showed that small amounts (0.05-1 wt%) of MWCNT treated using these methods increased the glass transition temperature, storage modulus, and strength of epoxy composites, with titania coating of MWCNT giving increases of up to 30% and 10°C, respectively. Non-covalent treatments generally improved properties more than co
This document discusses the use of positron annihilation spectroscopy to analyze the free volume nanohole distribution in polymers and its correlation to the physico-chemical properties of polymers. It provides background on positron annihilation spectroscopy and how it can be used to measure free volume in polymers. The document then describes several studies that use this technique to analyze the influence of free volume properties on the swelling of polymer hydrogels, structure-property relationships in modified epoxy resins, and free volume and interfacial interactions in epoxy clay composites.
This document describes a study that analyzed electromagnetic radiation and radon signals recorded before 37 earthquakes in Greece between 2007-2015 with magnitudes over 5.0 on the local scale. The study applied fractal analysis to examine the signals for long-memory patterns and critical behavior. The results found that the majority of signals exhibited characteristic epochs with fractal organization, including continuous epochs in some one-month electromagnetic signals. Many signals showed successive segments consistent with fractional Brownian motion, indicating long-range dependence away from randomness. Switching between persistent and anti-persistent behavior in some signals was considered an enhanced precursor. The findings suggest the signals displayed characteristics of self-organized critical states in the last stages of earthquake preparation.
Reservoir Characterization from Abnormal Pressure in Parts of Eleme, Southea...Scientific Review SR
This document analyzes well log data from two wells, Wells A and B, in Eleme, Nigeria to characterize abnormal reservoir pressures. Well logs including density, sonic, and acoustic impedance were interpreted to determine zones of abnormal pressure. For Well A, abnormal pressure was found between 2185-2785m, and for Well B between 1805-2525m. These zones had densities greater than 1.07kg/cm3 and pressure gradients exceeding normal hydrostatic gradients for the area. Accurately determining abnormal pressure zones is important for safely drilling wells in the region.
This document summarizes a study on the effect of different solvent systems on poly(lactic acid) (PLA) nanofibres produced through electrospinning. PLA solutions were prepared using various single solvents and mixed solvent systems. Of the single solvents tested, only acetone produced continuous nanofibres, while the others resulted in beads. The addition of acetone to other solvents in a 50/50 mixture improved fibre production. Solutions of acetone/dimethylformamide and acetone/dimethylacetamide produced smooth, bead-free nanofibres with the narrowest diameter distribution. The mixed solvent systems had lower viscosity and surface tension but higher conductivity than single solvents, enabling better fibre formation
Environ Sci Technol. 2007 Dec 15;41(24):8240-7.
Major structural components in freshwater dissolved organic matter.
Lam B, Baer A, Alaee M, Lefebvre B, Moser A, Williams A, Simpson AJ.
Department of Chemistry, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4.
Dissolved organic matter (DOM) contains a complex array of chemical components that are intimately linked to many environmental processes, including the global carbon cycle, and the fate and transport of chemical pollutants. Despite its importance, fundamental aspects, such as the structural components in DOM remain elusive, due in part to the molecular complexity of the material. Here, we utilize multidimensional nuclear magnetic resonance spectroscopy to demonstrate the major structural components in Lake Ontario DOM. These include carboxyl-rich alicyclic molecules (CRAM), heteropolysaccharides, and aromatic compounds, which are consistent with components recently identified in marine dissolved organic matter. In addition, long-range proton-carbon correlations are obtained for DOM, which support the existence of material derived from linear terpenoids (MDLT). It is tentatively suggested that the bulk of freshwater dissolved organic matter is aliphatic in nature, with CRAM derived from cyclic terpenoids, and MDLT derived from linear terpenoids. This is in agreement with previous reports which indicate terpenoids as major precursors of DOM. At this time it is not clear in Lake Ontario whether these precursors are of terrestrial or aquatic origin or whether transformations proceed via biological and/ or photochemical processes.
PMID: 18200846 [PubMed - indexed for MEDLINE]
This document discusses various pre-formulation studies including analytical methods used to characterize drug substances and formulations. It describes techniques such as microscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA) that are used to investigate the physical and chemical properties of drugs and excipients alone and in combination. Specific application and procedures for each technique are provided with examples.
Nanomaterials Article_Characterization of Hybrid Epoxy NanocompositesShelly Simcha
This document summarizes research on using different surface treatments of multi-walled carbon nanotubes (MWCNT) to improve the thermo-mechanical properties of epoxy nanocomposites. It reviews literature on MWCNT surface treatments including covalent methods like oxidation and non-covalent methods like surfactant adsorption and titania coating. Test results showed that small amounts (0.05-1 wt%) of MWCNT treated using these methods increased the glass transition temperature, storage modulus, and strength of epoxy composites, with titania coating of MWCNT giving increases of up to 30% and 10°C, respectively. Non-covalent treatments generally improved properties more than co
This document discusses the use of positron annihilation spectroscopy to analyze the free volume nanohole distribution in polymers and its correlation to the physico-chemical properties of polymers. It provides background on positron annihilation spectroscopy and how it can be used to measure free volume in polymers. The document then describes several studies that use this technique to analyze the influence of free volume properties on the swelling of polymer hydrogels, structure-property relationships in modified epoxy resins, and free volume and interfacial interactions in epoxy clay composites.
This document describes a study that analyzed electromagnetic radiation and radon signals recorded before 37 earthquakes in Greece between 2007-2015 with magnitudes over 5.0 on the local scale. The study applied fractal analysis to examine the signals for long-memory patterns and critical behavior. The results found that the majority of signals exhibited characteristic epochs with fractal organization, including continuous epochs in some one-month electromagnetic signals. Many signals showed successive segments consistent with fractional Brownian motion, indicating long-range dependence away from randomness. Switching between persistent and anti-persistent behavior in some signals was considered an enhanced precursor. The findings suggest the signals displayed characteristics of self-organized critical states in the last stages of earthquake preparation.
Reservoir Characterization from Abnormal Pressure in Parts of Eleme, Southea...Scientific Review SR
This document analyzes well log data from two wells, Wells A and B, in Eleme, Nigeria to characterize abnormal reservoir pressures. Well logs including density, sonic, and acoustic impedance were interpreted to determine zones of abnormal pressure. For Well A, abnormal pressure was found between 2185-2785m, and for Well B between 1805-2525m. These zones had densities greater than 1.07kg/cm3 and pressure gradients exceeding normal hydrostatic gradients for the area. Accurately determining abnormal pressure zones is important for safely drilling wells in the region.
This document summarizes a study on the effect of different solvent systems on poly(lactic acid) (PLA) nanofibres produced through electrospinning. PLA solutions were prepared using various single solvents and mixed solvent systems. Of the single solvents tested, only acetone produced continuous nanofibres, while the others resulted in beads. The addition of acetone to other solvents in a 50/50 mixture improved fibre production. Solutions of acetone/dimethylformamide and acetone/dimethylacetamide produced smooth, bead-free nanofibres with the narrowest diameter distribution. The mixed solvent systems had lower viscosity and surface tension but higher conductivity than single solvents, enabling better fibre formation
Environ Sci Technol. 2007 Dec 15;41(24):8240-7.
Major structural components in freshwater dissolved organic matter.
Lam B, Baer A, Alaee M, Lefebvre B, Moser A, Williams A, Simpson AJ.
Department of Chemistry, University of Toronto Scarborough, Toronto, Ontario, Canada M1C 1A4.
Dissolved organic matter (DOM) contains a complex array of chemical components that are intimately linked to many environmental processes, including the global carbon cycle, and the fate and transport of chemical pollutants. Despite its importance, fundamental aspects, such as the structural components in DOM remain elusive, due in part to the molecular complexity of the material. Here, we utilize multidimensional nuclear magnetic resonance spectroscopy to demonstrate the major structural components in Lake Ontario DOM. These include carboxyl-rich alicyclic molecules (CRAM), heteropolysaccharides, and aromatic compounds, which are consistent with components recently identified in marine dissolved organic matter. In addition, long-range proton-carbon correlations are obtained for DOM, which support the existence of material derived from linear terpenoids (MDLT). It is tentatively suggested that the bulk of freshwater dissolved organic matter is aliphatic in nature, with CRAM derived from cyclic terpenoids, and MDLT derived from linear terpenoids. This is in agreement with previous reports which indicate terpenoids as major precursors of DOM. At this time it is not clear in Lake Ontario whether these precursors are of terrestrial or aquatic origin or whether transformations proceed via biological and/ or photochemical processes.
PMID: 18200846 [PubMed - indexed for MEDLINE]
This document discusses various pre-formulation studies including analytical methods used to characterize drug substances and formulations. It describes techniques such as microscopy, differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA) that are used to investigate the physical and chemical properties of drugs and excipients alone and in combination. Specific application and procedures for each technique are provided with examples.
Diffusion phenomena, Drug release and dissolution
The document discusses key concepts related to diffusion including:
1. Diffusion is the movement of molecules from an area of high concentration to low concentration.
2. Fick's laws of diffusion describe the flux and rate of change of concentration over time for diffusing substances.
3. Membrane permeability and factors like thickness influence diffusion rates in drug delivery applications like transdermal patches.
The document discusses sustained release dosage forms. It begins by introducing drug delivery systems and how newer technologies have led to various techniques for delivering drugs. It then discusses the ideal properties of a drug delivery system, including maintaining therapeutic drug levels over an extended period of time and targeting the site of action. The document goes on to define and compare different types of modified release dosage forms such as sustained release, controlled release, and timed/delayed release forms. It provides details on the advantages and limitations of sustained release dosage forms.
This document discusses various aspects of drug release and dissolution. It begins by defining the five types of dosage forms that can be characterized by in vitro release, including solid oral dosage forms. It then discusses key concepts like drug products, drug substances, drug release mechanisms for different release types (immediate, delayed, extended), and modified-release dosage forms. The document also provides the definitions and differences between dissolution-controlled systems, diffusion-controlled systems, and combined dissolution-diffusion systems. It introduces mathematical models for drug dissolution like the Noyes-Whitney equation and Hixson-Crowell cube root equation. Finally, it discusses factors that affect drug dissolution and release rates.
Group4.plasma surface modification of polylactic acid to promoteRoy Rodriguez Solano
Plasma surface modification of polylactic acid (PLA) films was investigated using a dielectric barrier discharge (DBD) operating at medium pressure in different atmospheres. After plasma treatment, water contact angle measurements showed increased hydrophilicity of the PLA surface. X-ray photoelectron spectroscopy revealed an increased oxygen content on treated surfaces. Cell culture tests found that plasma treatment improved initial fibroblast cell attachment and morphology compared to untreated PLA, though no difference in proliferation was observed after 7 days. Plasma treatment in air was determined to be the most economical option for modifying PLA surfaces to enhance cell interactions.
Vesicular Dosage Forms - Evaluation of vesicular dosage formsSagar Savale
The document discusses various vesicular dosage forms including liposomes, niosomes, and multiple emulsions. It provides details on their characterization including evaluating shape and lamellarity using techniques like atomic force microscopy, transmission electron microscopy, and NMR. It also discusses determining size and size distribution using methods like light scattering, measuring surface charge via zeta potential, and assessing encapsulation efficiency. The document outlines characterizing these drug delivery systems through physical, chemical, and biological tests and providing an overview of niosomes and multiple emulsions.
The document discusses the two-step process of pulmonary surfactant adsorption to an air-water interface. The initial step slowly reduces surface tension to around 35-50 mN/m. The later step then accelerates further to the final tension of around 25 mN/m. Experiments show that lysophosphatidylcholine (LPC) and DSPE-PEG inhibit the later fusion step by disrupting lipid structure and stability, but have mixed effects on the initial step, either delaying or accelerating the rate. This supports a model where the initial step involves decreased lipid ordering, while the later step requires formation of a negatively curved stalk structure through vesicle fusion.
Optimization of Fibronectin Micro-contact Printing Protocol for PotentialLaura McGimpsey
This study optimized a micro-contact printing protocol to pattern fibronectin for potential nanoparticle uptake studies using endothelial cells. Different weights were tested during the micro-contact printing process and 20 grams was found to produce the most uniform fibronectin intensity across patterned areas and provided the most accurate coverage of the targeted 2500 μm2 area. This optimized 20 gram weight protocol will be adopted for future studies analyzing how cell cytoskeletal alignments influenced by patterned areas affect nanoparticle uptake in endothelial cells.
This document discusses experiments performed using dipalmitoyl-phosphatidic acid (DPPA) as a model system to study the properties of aerosols and their interaction with ocean surface films. DPPA was chosen because its components mimic those in ocean surface films. The document describes setting up a Langmuir trough to compress DPPA monolayers on water and salt water subphases and measure the changes in surface pressure. Preliminary data on the surface pressure-area isotherms of DPPA are presented, and future work is proposed to further study DPPA behavior under different conditions.
1. The document analyzes the degradation of PLGA and PGA-co-PDL polymeric nanoparticles (NPs) in simulated lung fluid (SLF) for pulmonary drug delivery applications.
2. Results showed PLGA NPs reduced in size over time, indicating degradation, while PGA-co-PDL NPs aggregated and increased in size.
3. PLGA NPs produced a more acidic environment as they degraded, which could potentially cause more inflammation than PGA-co-PDL NPs in vivo.
Osmotic drug delivery uses the osmotic pressure of drug or other solutes (osmogens or osmagents) for controlled delivery of drugs. Osmotic drug delivery has come a long way since Australian physiologists Rose and Nelson developed an implantable pump in 1955.
Roadshow2014 - presentazione Giovanna Fragneto (4 giugno 2014)Roadshow2014
The document summarizes Giovanna Fragneto's presentation on using neutron scattering techniques like diffraction, SANS, and reflectometry to study soft matter and biological structures. It provides examples of using these techniques to determine the structure of RNA complexes, membrane proteins, lipid bilayers, and protein adsorption on surfaces. Neutron scattering is well-suited for these applications because it is non-destructive and hydrogen and deuterium have similar scattering lengths, allowing selective deuteration for contrast variation.
This document describes a study that characterized the major and minor groove environments of DNA using fluorescent probes. Specifically:
- Fluorescent oligonucleotides were created by incorporating a dansyl fluorophore into the major groove at specific sites.
- The fluorescence properties of these probes were used to estimate that the dielectric constant of the major groove is around 55D, compared to 20D for the minor groove.
- Binding of the minor groove ligand netropsin could be quantitatively monitored by changes in fluorescence of the dansyl group in the major groove, suggesting an information network between the two grooves.
Ab experiments of fluid flow in polymer microchannelShaelMalik
1) The document discusses a computational fluid dynamics (CFD) study of droplet formation in a microfluidic cross-junction when the dispersed phase is a non-Newtonian fluid.
2) Simulations were performed using OpenFOAM to model droplet formation of xanthan gum solutions (shear thinning) in canola oil (Newtonian) across varying xanthan concentrations.
3) The results show that increasing the xanthan concentration leads to longer thread detachment times, wider thread widths at the junction entrance, and smaller dimensionless droplet diameters, demonstrating the impact of shear thinning behavior on droplet formation.
This document discusses testing the chemical resistance of PEDOT (poly(3,4-ethylenedioxythiophene)) coated on textile substrates via vapor phase polymerization. Samples were submerged in various organic and inorganic solvents for up to 72 hours. 10% sodium hydroxide most significantly increased electrical resistance over time, removing the PEDOT layer. Tetrahydrofuran removed the PEDOT layer within 24 hours. Weight loss correlated with decreasing conductivity. Scanning electron microscopy images showed PEDOT removal from sodium hydroxide and THF treated samples.
This document discusses osmotic drug delivery systems. It begins with an introduction to how osmotic drug delivery uses osmotic pressure for controlled drug delivery. It then covers the basic principles of osmosis, classification of osmotic delivery systems, factors affecting drug release, and basic components. The document lists advantages like achievable zero-order release and independence from gastric conditions. Disadvantages include potential for dose dumping. Materials used in formulation are also outlined.
The document discusses improving the performance of photopolymer resins used in 3D printing through oxygen desensitization. It examines adding visco enhancers and antioxidants to photopolymer resins to protect the ruthenium catalyst from deactivating in the presence of oxygen. Testing found that increasing the resin viscosity by 30x improved its ambient lifespan by over 100x. Adding the antioxidant 4-methoxyphenol (MEHQ) at 0.1-0.2 wt.% also improved performance by 9x. Raman spectroscopy confirmed MEHQ was the most effective antioxidant at protecting the catalyst compared to others tested. The modifications aim to allow photopolymer resins to polymerize after longer exposures to ambient oxygen levels.
The document discusses targeted drug delivery using polymeric nanoparticles. It defines targeted drug delivery and introduces various concepts like bioavailability, drug receptors, and mechanisms of targeting like passive and active targeting. It describes different carrier systems used for targeted delivery, including vesicular systems, microparticles, cellular carriers, and polymer-based systems. The document also discusses factors affecting nanoparticle biodistribution, various techniques for producing polymeric nanoparticles, and methods of surface modification to reduce nanoparticle uptake by the mononuclear phagocytic system and increase blood circulation time.
Diffusion phenomena, Drug release and dissolution
The document discusses key concepts related to diffusion including:
1. Diffusion is the movement of molecules from an area of high concentration to low concentration.
2. Fick's laws of diffusion describe the flux and rate of change of concentration over time for diffusing substances.
3. Membrane permeability and factors like thickness influence diffusion rates in drug delivery applications like transdermal patches.
The document discusses sustained release dosage forms. It begins by introducing drug delivery systems and how newer technologies have led to various techniques for delivering drugs. It then discusses the ideal properties of a drug delivery system, including maintaining therapeutic drug levels over an extended period of time and targeting the site of action. The document goes on to define and compare different types of modified release dosage forms such as sustained release, controlled release, and timed/delayed release forms. It provides details on the advantages and limitations of sustained release dosage forms.
This document discusses various aspects of drug release and dissolution. It begins by defining the five types of dosage forms that can be characterized by in vitro release, including solid oral dosage forms. It then discusses key concepts like drug products, drug substances, drug release mechanisms for different release types (immediate, delayed, extended), and modified-release dosage forms. The document also provides the definitions and differences between dissolution-controlled systems, diffusion-controlled systems, and combined dissolution-diffusion systems. It introduces mathematical models for drug dissolution like the Noyes-Whitney equation and Hixson-Crowell cube root equation. Finally, it discusses factors that affect drug dissolution and release rates.
Group4.plasma surface modification of polylactic acid to promoteRoy Rodriguez Solano
Plasma surface modification of polylactic acid (PLA) films was investigated using a dielectric barrier discharge (DBD) operating at medium pressure in different atmospheres. After plasma treatment, water contact angle measurements showed increased hydrophilicity of the PLA surface. X-ray photoelectron spectroscopy revealed an increased oxygen content on treated surfaces. Cell culture tests found that plasma treatment improved initial fibroblast cell attachment and morphology compared to untreated PLA, though no difference in proliferation was observed after 7 days. Plasma treatment in air was determined to be the most economical option for modifying PLA surfaces to enhance cell interactions.
Vesicular Dosage Forms - Evaluation of vesicular dosage formsSagar Savale
The document discusses various vesicular dosage forms including liposomes, niosomes, and multiple emulsions. It provides details on their characterization including evaluating shape and lamellarity using techniques like atomic force microscopy, transmission electron microscopy, and NMR. It also discusses determining size and size distribution using methods like light scattering, measuring surface charge via zeta potential, and assessing encapsulation efficiency. The document outlines characterizing these drug delivery systems through physical, chemical, and biological tests and providing an overview of niosomes and multiple emulsions.
The document discusses the two-step process of pulmonary surfactant adsorption to an air-water interface. The initial step slowly reduces surface tension to around 35-50 mN/m. The later step then accelerates further to the final tension of around 25 mN/m. Experiments show that lysophosphatidylcholine (LPC) and DSPE-PEG inhibit the later fusion step by disrupting lipid structure and stability, but have mixed effects on the initial step, either delaying or accelerating the rate. This supports a model where the initial step involves decreased lipid ordering, while the later step requires formation of a negatively curved stalk structure through vesicle fusion.
Optimization of Fibronectin Micro-contact Printing Protocol for PotentialLaura McGimpsey
This study optimized a micro-contact printing protocol to pattern fibronectin for potential nanoparticle uptake studies using endothelial cells. Different weights were tested during the micro-contact printing process and 20 grams was found to produce the most uniform fibronectin intensity across patterned areas and provided the most accurate coverage of the targeted 2500 μm2 area. This optimized 20 gram weight protocol will be adopted for future studies analyzing how cell cytoskeletal alignments influenced by patterned areas affect nanoparticle uptake in endothelial cells.
This document discusses experiments performed using dipalmitoyl-phosphatidic acid (DPPA) as a model system to study the properties of aerosols and their interaction with ocean surface films. DPPA was chosen because its components mimic those in ocean surface films. The document describes setting up a Langmuir trough to compress DPPA monolayers on water and salt water subphases and measure the changes in surface pressure. Preliminary data on the surface pressure-area isotherms of DPPA are presented, and future work is proposed to further study DPPA behavior under different conditions.
1. The document analyzes the degradation of PLGA and PGA-co-PDL polymeric nanoparticles (NPs) in simulated lung fluid (SLF) for pulmonary drug delivery applications.
2. Results showed PLGA NPs reduced in size over time, indicating degradation, while PGA-co-PDL NPs aggregated and increased in size.
3. PLGA NPs produced a more acidic environment as they degraded, which could potentially cause more inflammation than PGA-co-PDL NPs in vivo.
Osmotic drug delivery uses the osmotic pressure of drug or other solutes (osmogens or osmagents) for controlled delivery of drugs. Osmotic drug delivery has come a long way since Australian physiologists Rose and Nelson developed an implantable pump in 1955.
Roadshow2014 - presentazione Giovanna Fragneto (4 giugno 2014)Roadshow2014
The document summarizes Giovanna Fragneto's presentation on using neutron scattering techniques like diffraction, SANS, and reflectometry to study soft matter and biological structures. It provides examples of using these techniques to determine the structure of RNA complexes, membrane proteins, lipid bilayers, and protein adsorption on surfaces. Neutron scattering is well-suited for these applications because it is non-destructive and hydrogen and deuterium have similar scattering lengths, allowing selective deuteration for contrast variation.
This document describes a study that characterized the major and minor groove environments of DNA using fluorescent probes. Specifically:
- Fluorescent oligonucleotides were created by incorporating a dansyl fluorophore into the major groove at specific sites.
- The fluorescence properties of these probes were used to estimate that the dielectric constant of the major groove is around 55D, compared to 20D for the minor groove.
- Binding of the minor groove ligand netropsin could be quantitatively monitored by changes in fluorescence of the dansyl group in the major groove, suggesting an information network between the two grooves.
Ab experiments of fluid flow in polymer microchannelShaelMalik
1) The document discusses a computational fluid dynamics (CFD) study of droplet formation in a microfluidic cross-junction when the dispersed phase is a non-Newtonian fluid.
2) Simulations were performed using OpenFOAM to model droplet formation of xanthan gum solutions (shear thinning) in canola oil (Newtonian) across varying xanthan concentrations.
3) The results show that increasing the xanthan concentration leads to longer thread detachment times, wider thread widths at the junction entrance, and smaller dimensionless droplet diameters, demonstrating the impact of shear thinning behavior on droplet formation.
This document discusses testing the chemical resistance of PEDOT (poly(3,4-ethylenedioxythiophene)) coated on textile substrates via vapor phase polymerization. Samples were submerged in various organic and inorganic solvents for up to 72 hours. 10% sodium hydroxide most significantly increased electrical resistance over time, removing the PEDOT layer. Tetrahydrofuran removed the PEDOT layer within 24 hours. Weight loss correlated with decreasing conductivity. Scanning electron microscopy images showed PEDOT removal from sodium hydroxide and THF treated samples.
This document discusses osmotic drug delivery systems. It begins with an introduction to how osmotic drug delivery uses osmotic pressure for controlled drug delivery. It then covers the basic principles of osmosis, classification of osmotic delivery systems, factors affecting drug release, and basic components. The document lists advantages like achievable zero-order release and independence from gastric conditions. Disadvantages include potential for dose dumping. Materials used in formulation are also outlined.
The document discusses improving the performance of photopolymer resins used in 3D printing through oxygen desensitization. It examines adding visco enhancers and antioxidants to photopolymer resins to protect the ruthenium catalyst from deactivating in the presence of oxygen. Testing found that increasing the resin viscosity by 30x improved its ambient lifespan by over 100x. Adding the antioxidant 4-methoxyphenol (MEHQ) at 0.1-0.2 wt.% also improved performance by 9x. Raman spectroscopy confirmed MEHQ was the most effective antioxidant at protecting the catalyst compared to others tested. The modifications aim to allow photopolymer resins to polymerize after longer exposures to ambient oxygen levels.
The document discusses targeted drug delivery using polymeric nanoparticles. It defines targeted drug delivery and introduces various concepts like bioavailability, drug receptors, and mechanisms of targeting like passive and active targeting. It describes different carrier systems used for targeted delivery, including vesicular systems, microparticles, cellular carriers, and polymer-based systems. The document also discusses factors affecting nanoparticle biodistribution, various techniques for producing polymeric nanoparticles, and methods of surface modification to reduce nanoparticle uptake by the mononuclear phagocytic system and increase blood circulation time.
Preparation and characterization of nimesulide loaded cellulose acetate hydro...Jing Zang
This document summarizes a study that prepared nimesulide-loaded cellulose acetate hydrogen phthalate nanoparticles using the salting out technique. The effect of drug concentration and polymer concentration on nanoparticle size, shape, and uniformity was investigated. Increasing the polymer concentration decreased nanoparticle size and improved uniformity. Drug concentration did not affect size. Nanoparticles were characterized using SEM, zeta potential analysis, and photon correlation spectroscopy. The mean nanoparticle size was 548.2 nm with a zeta potential of -19.8 mV, indicating stability.
We present a micro fluidic device that allows rapid and defined delivery of discrete and homogeneous reagents or samples to allow kinetic studies of surface-tethered biomolecules. We developed an Electro Osmotic Flow (EOF) based device consisting of an asymmetric Y-junction with an incorporated fast, pressure driven valve, two embedded measurement electrodes and reservoirs. The EOF is used to circumvent kinetic limitations on reagent transport to the surface of these tethered biomolecules due to the slow diffusion across parabolic concentration gradients in conventional pressure-driven flow devices. Using Fluorescein isothiocyanate (FITC) as the pH sensitive surface-immobilized biomolecules, we show that the reagent solution can be repeatedly exchanged within milliseconds, and that by using a synchronized triggering scheme we can monitor the reaction of our sensor biomolecules to the change of the environment on a time scale of 10ms.
characterization of Nanoparticles note.pdfyusufzako14
This document discusses characterization techniques for nanoparticles. It begins with an introduction to nanoparticles and then describes various methods to characterize their size, shape, surface charge, drug entrapment efficiency, release kinetics, and stability. Specifically, it details techniques like dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and in vitro drug release studies using apparatus like basket and paddle systems or dialysis methods. The document provides examples and diagrams to explain characterization parameters and instrumentation.
1. Effect of polymeric nanoparticles
on the stability of a biomimetic
model of the lung surfactant
Weiam Daear MSc. Student
Supervisor: Dr. Elmar Prenner
University of Calgary
Alberta, Canada
1
2. 1. Introduction: Drug Delivery Routes
2
Mitragotri, S. 2008. The Bridge 38(4): 5-12
Parenteral delivery:
Intravenous. Delivery
through injections.
Transdermal delivery:
Delivery through skin patches
or lotions.
Oral delivery:
Liquid or pill delivery through ingestion. Large
blood supply but subject to pH degradation.
Pulmonary delivery:
Delivery through the lungs using aerosols.
Close proximity to blood circulation
(Heart).
Nasal delivery:
Delivery through the nasal cavity.
Close proximity to the brain.
Ocular delivery:
Delivery through
the eyes e.g. eye drops.
• There is no one route that is better than the other, it all depends on the nature of the
drug and the target location.
3. 1. Introduction: Pulmonary Drug Delivery Route
• The distance between the air and the
blood is around 500-800 nm.
• Lung surfactant is the first point of
interaction of the pulmonary delivery
route.
• Lung surfactant is a monolayer consisting
of:
– 90% lipids
• 10% neutral lipids
(e.g. Cholestrol)
• 80% phospholipids
– 10% surfactant proteins
• A major role of the lung surfactant is to
reduce the surface tension to values
closer to zero in order to prevent lung
collapse.
Piknova, B. et al. 2002 Current Opinion in Structural Biology
Agassandian M. and Mallampalli R.K. 2013 Biochemica et Biophysica Acta 1831:612-625
3
4. Drug
Targeting molecule
• There is a constantly growing need
for an optimal drug delivery with high
efficiency, specificity, and stability.
• Drugs can be either be encapsulated
or adsorbed onto the surface of
nanoparticles (NPs). Nanoparticles
are generally within few hundred
nanometers in size.
• Advantages of using NPs as drug
delivery vehicles:
– Can penetrate tissues/cells of target organ
– Ability to exhibit controlled release
1. Introduction: Nanoparticles for Drug Delivery
4
Peer, D. et al. 2007 Nature Nanotechnology 5: 751-760
5. 1. Introduction: Nanoparticles for Drug Delivery
• Examples of Nanoparticles (NPs):
– Polymeric NPs
• Gelatin
• Poly(lactide-co-glycolic acid), PLGA
• Poly-n-(butyl)cyanoacrylates, PBCA
– Dendrimers
• Chain of repeating molecules
– Liposomes/micelles
• Lipid based
5
PLGA
PBCA
Peer, D. et al. 2007 Nature Nanotechnology 5: 751-760
This research focuses on polymeric NPs due
to their high stability, biocompatibility and
biodegradability.
6. 2. Research Goals
• Goal 1:
– Develop a biomimetic model of the lung surfactant.
• Goal 2:
– Analyze and understand how the nature of polymeric
nanoparticles affect the stability of the lung surfactant monolayer.
• Gelatin, PLGA, and PBCA nanoparticles
• Goal 3:
– Understand the localization of different polymeric nanoparticles
with the lung surfactant monolayer.
6
7. • Lung surfactant lipid analysis:
– Postle et al. performed mass spectroscopy analysis on the lipid composition of the lung surfactant.
The major lipid classes are phosphatidylcholines (PCs) and phosphatidylglycerols (PGs).
– Based on the results, the 16:0/16:0 and 16:0/18:1 PCs and PGs were chosen for biomimetic model.
3. Research Methods
Postle A.D. et al. 2001Comparative Biochemistry and Physiology Part A 129: 65-73
7
8. 3. Research Methods
• Lung surfactant lipid biomimetic model: (mol ratios)
– 45 1,2-dipalmitoylphosphatidyl-choline, DPPC
– 1 1,2-dipalmitoylphosphatidyl-glycerol, DPPG
– 8 1-palmitoyl-2-oleoylphosphatidyl-choline, POPC
– 6 1-palmitoyl-2-oleoylphosphatidyl-glycerol, POPG
• The double bond introduces fluidity to the lipid. The two major
driving factors in the model are : The Overall charge and Fluidity.
8
16:0 /16:0 PC (DPPC)
Overall charge: 0PC
16:0/16:0 PG (DPPG)
Overall charge: -1PG
Overall charge: -1
16:0/18:1Δ9 PG (POPG)
PG
16:0/18:1Δ9 PC (POPC)
Overall charge: 0PCDouble bond
Postle A.D. et al. 2001Comparative Biochemistry and Physiology Part A 129: 65-73
2 % Cholesterol of the
total lipid weight
+
9. • Studies on the lung surfactant is done using a Langmuir Trough.
– A movable barrier is used to mimic compression of the lung surfactant during exhalation.
– Monolayer compression causes an increase in surface pressure recorded by a sensor.
3. Research Methods: Langmuir Trough
Pressure Sensor
Movable Barrier
Aqueous layer
Lipids deposited on aqueous layer
10. 3. Research Methods: Langmuir Trough
He and Li 2007 Advances in Colloid and Interface Science 131: 91-98
10
• The change in surface pressure as the area changes with compression is recorded as a
Pressure – Area isotherms (π-A isotherms).
• As the monolayer is being compressed, it undergoes different lipid phases.
• G: Gaseous phase
• LE: Liquid Expanded
• LC: Liquid Condensed
Area per molecule
G phase
LE phase
LE-LC
LC phase
Collapse
• Further compression results in monolayer
collapse (multilayer structures) which is
known as “Collapse Pressure”.
• Surface pressure and surface tension are
inversely proportional.
• A decrease in collapse pressure is a measure
of monolayer stability.
Direction of compression
11. 3. Research Methods: Brewster Angle Microscopy
• Brewster Angle Microscopy (BAM)
– Allows visualization of the lateral domain organization of the monolayer.
– Plane polarized light is directed at the air-water interface at the Brewster angle
where no light is reflected. This angle (θ) is determined through Snell’s law:
tanθ = n2/n1
– For the air-water interface, θ is equal to 53.1º,
Image adapted from www.ksvnima.com
11
12. 4. Results: DPPC system
12
• As shown by Lai et al., collapse pressure
of pure DPPC is around 60 mN/m. This
collapse pressure is not reduced
significantly with the addition of gelatin
NPs.
• This indicates that gelatin NPs had no
effect on the stability of DPPC.
DPPC, overall
charge: 0
Lai, P. et al. 2009 Journal of Biomedical Technology 6(2): 145-152
This paper shows the effect of gelatin NPs on
the major lung surfactant lipid constituent,
DPPC. I want to test the effect on other
major lipid classes and associated complex
mixtures for the development of a
biomimetic lung surfactant model.
13. 4. Results: DPPC system
• DPPC interaction with gelatin NPs:
• At a surface pressure of ~7 mN/m:
– Gelatin NPs decreased the size of the DPPC lateral domains.
– The decrease in the DPPC domain size is correlated to the concentration of NPs
being added.
13
DPPC:Nanoparticles
(30:1 w/w)DPPC
DPPC:Nanoparticles
(11:1 w/w)
Bar: 50 µm
DPPC, overall
charge: 0
Lai, P. et al. 2009 Journal of Biomedical Technology 6(2): 145-152
14. • POPC interaction with gelatin NPs:
• Collapse pressure of POPC is not reduced
by the addition of gelatin NPs.
• This indicates that gelatin NPs have no
effect on the stability of POPC.
• Small reduction in molecular area due to
the addition of gelatin NPs indicate minor
lipid loss to the aqueous layer.
4. Results: POPC system
14
0
5
10
15
20
25
30
35
40
45
50
0 50 100 150 200 250 300
SurfacePressure(mN/m)
Area (Ų/molecule)
POPC
POPC + NPs
POPC, overall
charge: 0
15. • POPC interaction with gelatin NPs :
• At a surface pressure of ~5 mN/m:
– Gelatin NPs had a minor effect on the POPC monolayer lateral organization.
– When comparing DPPC to POPC, the major difference is the level of acyl chain
saturation (fluidity). This mono-unsaturation prevents the formation of domains.
4. Results: POPC system
15Bar: 50 µm
POPC
POPC:Nanoparticle
(10:1 w/w)
Bright spots due to addition of NPs
POPC, overall
charge: 0
16. 16
4. Results: Binary PC system
16
• Binary PC (45 DPPC+ 8 POPC)
interaction with gelatin NPs:
• Collapse pressure of Binary PC is not
reduced by the addition of gelatin NPs.
• This indicates that gelatin NPs have no
effect on the stability of Binary PC system.
• A significant shift in the π-A isotherm to
larger molecular areas is observed. This
indicates NP adsorption/insertion into the
monolayer film.
-10
0
10
20
30
40
50
60
70
0 50 100 150 200 250
SurfacePressure(mN/m)
Area (Ų/molecule)
Binary PC
Binary PC with NPs
DPPC, overall
charge: 0
POPC, overall
charge: -1
17. 1717
• Binary PC interaction with gelatin NPs:
• At surface pressures of ~ 13 mN/m and 25 mN/m:
– Gelatin NPs decreased the frequency of the lateral domains observed.
Bar: 50 µm
DPPC+POPC
Binary PC:Nanoparticle
(10:1 w/w) DPPC+POPC
Binary PC:Nanoparticle
(10:1 w/w)
At 13 mN/m At 25 mN/m
4. Results: Binary PC system DPPC, overall
charge: 0
POPC, overall
charge: -1
18. 4. Results: DPPG system
18
-10
0
10
20
30
40
50
60
0 50 100 150 200SurfacePressure(mN/m)
Area (Ų/molecule)
DPPG
DPPG + NPs
• DPPG interaction with gelatin
NPs:
• Collapse pressure of DPPG is reduced by
~ 5 mN/m due to the addition of gelatin
NPs.
DPPG, overall
charge: -1
19. 4. Results: DPPG system
191919
Bar: 50 µm
DPPG
DPPG:Nanoparticle
(10:1 w/w) DPPG
DPPG:Nanoparticle
(10:1 w/w)
At 10 mN/m At 30 mN/m
• DPPG interaction with gelatin NPs:
• At a surface pressures of ~ 10 mN/m and 30 mN/m:
– Gelatin NPs did not have an effect on the observed domain size but appear to
localize at the edges of the domains. (arrows indicate localization)
DPPG, overall
charge: -1
20. 4. Results: Quaternary system
20
4 lipid system interaction with gelatin
NPs:
• Collapse pressure of 4 lipid system is not
reduced by the addition of gelatin NPs.
• Small reduction in molecular area due to
the addition of gelatin NPs indicate change
in lipid packing or minor lipid loss to the
aqueous layer.
-10
0
10
20
30
40
50
60
0 20 40 60 80 100 120
SurfacePressure(mN/m)
Area (Ų/molecule)
4 lipid
4 lipid + NPs
Complex mixture-1 (48 DPPC+ 8 POPC+ 1 DPPG+ 6 POPG)
DPPC, overall
charge: 0
POPC, overall
charge: -1
DPPG, overall
charge: -1
POPG, overall
charge: -1
21. 4. Results: Quaternary system
21
• 4 lipid system interaction with gelatin NPs:
• At surface pressures of 15 mN/m and 30 mN/m:
– Gelatin NPs appear to have an effect on domain size and frequency.
Bar: 50 µm
4 lipid
4 lipid:Nanoparticle
(10:1 w/w) 4 lipid
4 lipid:Nanoparticle
(10:1 w/w)
At 15 mN/m At 30 mN/m
Bar: 50 µm
DPPC, overall
charge: 0
POPC, overall
charge: -1
DPPG, overall
charge: -1
POPG, overall
charge: -1
22. 4. Results: Quinary system
22
-10
0
10
20
30
40
50
60
0 20 40 60 80 100 120
SurfacePressure(mN/m)
Area (Ų/molecule)
4 lipid + Chol
4 lipid + Chol + NPs
4 lipid system + Cholesterol
interaction with gelatin NPs:
• Collapse pressure of 4 lipid+Cholesterol
system is not reduced by the addition of
gelatin NPs.
• Small reduction in molecular area due to
the addition of gelatin NPs indicate change
in lipid packing or minor lipid loss to the
aqueous layer.
• The plateau indicated by the arrow ( )
resembles that seen with BLES (Bovine
Lipid Extract Surfactant).
DPPC, overall
charge: 0
POPC, overall
charge: -1
DPPG, overall
charge: -1
POPG, overall
charge: -1
Complex mixture-2 (48 DPPC+ 8 POPC+ 1 DPPG+ 6 POPG + 2%w/w Cholesterol )
23. • 4 lipid system + Cholesterol interaction with gelatin NPs:
• At surface pressures of 25 mN/m
– When comparing this system to the 4 lipid system, it can be concluded that
Cholesterol appears to have a significant effect on domain formation.
– Gelatin NPs had a minor effect on the POPC monolayer lateral organization.
4. Results: Quinary system
2323
Bar: 50 µm
4 lipid+Chol
4 lipid+Chol:Nanoparticle
(10:1 w/w)
DPPC, overall
charge: 0
POPC, overall
charge: -1
DPPG, overall
charge: -1
POPG, overall
charge: -1
24. 5. Conclusions
• Isotherms indicate there is no destabilization with the addition of gelatin NPs.
• BAM allowed the visualization of lateral domain organization.
• Increasing the fluidity of the lipid system through a single double bond (DPPC
POPC) appears to prevent lateral domain formation.
• Binary PC system pressure-area isotherm shift to the larger with the addition of NPs
indicating an insertion/adsorption mode of gelatin NP localization.
• With other measured systems, the addition of gelatin NPs slightly increased the area
indicating an effect on lipid packing or lipid loss to the aqueous layer.
• The addition of Cholesterol to the 4 lipid system affects lipid packing and prevents
the formation of the observable lateral domains.
24
25. 6. Future Directions
25
• Test how the different chemical nature of polymeric NPs affect the
observed results.
– PLGA and PBCA NPs
• Use fluorescence imaging of NPs to test the localization of NPs
within the lung surfactant.
26. 7. Acknowledgement
26
o Funding by Queen Elizabeth II Graduate Scholarship
o Special Thanks to:
• Dr. Elmar Prenner, University of Calgary (Supervisor),
• Sigma Xi for providing such an opportunity, and
• Mohamed Hassanin for help with creating the presentation site.