Chemical Engineering Commons^™

Comparative Analysis Of The Dissolution Performance Of Aspirin Tablets In The Usp Apparatus 2 And In A Minivessel Dissolution System, Annmarie C. Walker

Theses

Dissolution testing is a critical component of quality control procedures in the pharmaceutical industry in order to ensure that the final solid dosage forms have consistent dissolution properties. Dissolution tests are also routinely conducted to evaluate the in-vitro performance of solid dosage forms during pharmaceutical development, to aid in the behavior of formulations, and to optimize drug release from dosage forms.

The use of compendial dissolution test apparatus and techniques, such as the USP 2 (Paddle), to characterize the dissolution performance of oral drug delivery system is an established area of pharmaceutical science. However, this method is not always appropriate, …

Co2 Reduction Over Noble Metal/Carbon Nanotube Catalyst, Yuan Zhu

Dissertations

Carbon nanotube-based Pt/Pd and Ru catalysts, independently synthesized by a microwave reaction technique, show good catalytic activity for CO2 reduction in the contexts of dry reforming (DR) of methane (CH₄ + CO₂ -> 2CO + 2H₂) and reverse water gas shift (RWGS) (H2 + CO₂ -> CO + H₂O). Reaction temperatures range from 773 to 973 K, with system pressure at 30 psig. The feed molar ratios CH4/CO₂ and CO₂/H₂ are varied from 0.5 to 2.0. Reactant conversions in DR and RWGS are strongly influenced by temperature and feed …

Characterization Of Microporous Ectfe Membranes Exposed To Different Liquid Media And ?-Radiation And Nanoparticle Microfiltration Through Such Membranes, Na Yao

Dissertations

Microporous polymeric membranes are used in a variety of applications for separations, purification as well as barrier function. A major application is for microfiltration (MF). Changes in the properties of MF membranes exposed to acids, bases and organic solvents are of interest in semiconductor processing as well as in membrane contactor applications. Microfiltration membranes used for sterilization in beverage, biotechnology and pharmaceutical industries are sterilized by gamma radiation among others. Irradiation-induced degradation in membrane properties should be known. A variety of fluoropolymer-based microporous membranes are available with varying properties. Ethylene chlorotrifluoroethylene (ECTFE) membranes are a new addition and are of …

Formulation And Dissolution Of Polymer Strip Films For The Delivery Of Poorly Water-Soluble Drug Nanoparticles, Scott Matthew Krull

Dissertations

Polymer films have emerged as a promising platform for delivery of pharmaceutical products in recent years due to simplified processing, greater flexibility, and improved patient compliance over traditional solid dosage forms. However, the large majority of efforts have focused on incorporation of water-soluble drugs. The objective of this dissertation is to explore the robustness and versatility of the strip film platform for delivery of poorly water-soluble drug nanoparticles to ultimately develop a predictive model for drug release from such films.

The robustness of the polymer strip film platform to successfully deliver a variety of poorly water-soluble drug nanoparticles without the …

Assessment Of Nanocomposites Vs. Amorphous Solid Dispersions For Dissolution Enhancement Of Bcs Class Ii Drugs, Meng Li

Dissertations

Nanoparticle-based formulations (nanocomposites) and amorphous solid dispersions, shortly ASDs, are two major pharmaceutical formulation platforms used for the bioavailability enhancement of poorly water-soluble drugs. While they both have several advantages-disadvantages, a scientific comparative assessment of their drug release performance and dissolution mechanisms at different drug doses is not available. With the goal of addressing this issue, the dissertation aims to achieve three major objectives: (1) develop a processing-formulation understanding of wet media milling process for fast-efficient production of drug nanoparticles in stable nanosuspension form, (2) elucidate the impact of various classes dispersants on drug release rate and mechanisms during the …

Nanocomposite Thermite Powders With Improved Flowability Prepared By Mechanical Milling, Ci Huang

Theses

Nanocomposite thermite powders are of interest to develop varieties of reactive parts and components. Manufacturing these components requires tailoring properties of the thermite powders such as their particle size distributions, particle shapes, and powder flowability. For example, an improved flowability is desired to use these powders as feedstock in additive manufacturing. Arrested reactive milling (ARM) offers a versatile and practical approach for preparing various nanocomposite thermites with fully dense particles, which will retain their structures and mixedness between reactive components while being stored, handled, and processed. However, ARM products usually have broad particle size distributions, rock-like particle shapes, and poor …

Thermal Swing Membrane Based Method For Co2 Capture From Flue Gas, Mukesh Kumar Kamad

Theses

Carbon dioxide, a greenhouse gas and a major contributor to global warming, is released in large amounts by flue gases. To limit climate change, such CO₂ emissions have to be reduced, CO₂ captured and sequestered. Conventional monoethanolamine (MEA)-based absorption techniques are costly due to high capital cost and high energy consumption since the absorbent has to be regenerated at a high temperature ~ 120°C. A temperature swing membrane absorption (TSMAB) process was described by Mulukutla et al. (2015) using a novel membrane contactor, novel absorbents and a cyclic process. In this device, the absorbent is on the shell …

Investigation Of Nh3 And No Adsorption Over Cu/Sapo-34 And Cu/Aloo3 Catalysts For Nh3–Scr System, Basil Rawah

Theses

In this study, Copper supported on SAPO-34 molecular sieves or alumina is prepared via an incipient wetness impregnation method for ammonia selective catalytic reduction (NH₃-SCR). These NH₃-SCR catalysts are characterized by pulse chemisorption, temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD) with three different conditions (NH₃, NO, combined NH₃-NO) to evaluate the adsorption of ammonia and nitric oxide. Cu/SAPO-34 catalyst has shown higher ammonia adsorption capacity compared to Cu/Al₂O₃ catalyst. The Cu/SAPO-34 adsorption is enhanced due to the strong acidity and high surface area of SAPO-34 molecular sieves. NO adsorption …

Power Dissipation And Power Correlations For A Retreatblade Impeller Under Different Baffling Conditions, Chadakarn Sirasitthichoke

Theses

Glass-lined stirred reactors and tanks are commonly used in the pharmaceutical industry because of their corrosion resistance, ease of cleanliness and minimization of product contamination. Most industrial glass-lined tank reactors are provided with a torispherical tank bottom and a retreat curve impeller with low impeller clearance from the vessel bottom. The power, P, dissipated by the impeller is a critical process parameter to mixing processes to achieve the desired mixing effect, especially since the power per unit volume, P/V, directly controls mass transfer processes and other mixing phenomena. However, little information has been published about the power dissipation and the …

High Performance Lattice Boltzmann Method Yield-Stress Calculations Based On Intravital Images Of Clot Formation In Live Mice, Vishnu Deep Chandran

Theses

Thrombo-embolic infarction is the major cause of mortality and morbidity in the United States, causing over 1 million strokes, heart attacks and other life-threatening thrombotic events each year in the United States. Conversely, deficiencies in these processes result in severe bleeding risks. The ability to access hydrodynamics stresses at which thrombus structure is likely to embolize can provide insight into the thrombogenesis process. Interestingly, the viscoelastic behavior exhibited by the thrombus resembles that of a Bingham fluid - a material that behaves as a rigid body at low stresses but flows as a viscous fluid when the stress exceeds critical …

Eis Analysis Of Shear Enhanced Microfluidic Lab-On-A-Chip Device, Mehnaz Mursalat

Theses

Electrochemical sensors and biosensors have received much attention owing to the feasibility demonstrated regarding instrumental simplicity, decent cost, and portability during the detection of a wide range of biological and pharmaceutical macromolecules. Carbon-based nanomaterials, including carbon nanotubes, have garnered tremendous interest for their unique thermal, mechanical, electronic and catalytic properties while designing these sensors. Whenever the macromolecules interact with a bio-recognition element on the electrode transducer surface, a measurable change in the electrical current or potential takes place. To achieve lower limits of detection, the use of sensor surfaces modified with nanostructured materials such as nanotubes, or nanoparticles is becoming …

Real Time, Integrated, Paper Based Temperature Sensor For Lab On A Chip Device, Vignesh Shekhar

Theses

Temperature measurement and manipulation is a critical factor in a wide range of applications like Point Of Care Diagnostics (POC's), Polymerase Chain Reaction (PCR), Temperature Gradient Focusing (TGF) to cite few prominent examples. In the past decade, researchers have used various techniques to sense and control the temperature in microfluidic systems. The primary challenge has been the twin problem of integration and accuracy using minimal equipment while keeping it simple. In this study, an equipment free fabrication of the temperature sensor using filter paper impregnated with p-type colloidal PbS quantum dots is demonstrated. This sensor is later integrated into line …

Novel Experimental Method For The Determination Of The Minimum Agitation Speed For Solids Suspension In Flat-Bottomed Stirred Tank Reactors, Shriarjun Shastry

Theses

Knowledge of the minimum agitation speed, Njs, required to suspend finely divided solids in vessels stirred by an impeller is a critical parameter to properly operate industrial tanks in a large number of industrial operations. The most common experimental approach to measure N_js is that of Zwietering’s (Chem. Eng. Sci., 1958, 8, 244-253), consisting of visually inspecting the tank bottom and visually determining the impeller agitation speed at which the solids are observed to rest on the tank bottom for no more than 1-2 seconds before being swept away. This method is quite reliable, but a method …

Processing Of Cds/Cdte Solar Cell And The Growth Model Of Cdte Thin Film, Guogen Liu

Dissertations

Cadmium telluride is the only thin film photovoltaic (PV) technology to surpass crystalline silicon PV in the cost. The most common CdTe solar cells consist of a simple p-n heterojunction structure containing a p-doped CdTe layer and n-doped cadmium sulfide (CdS) layer, which acts as a window layer. Cadmium Sulfide (CdS) thin films are often deposited on glass substrates coated with TCO layers by the close-spaced sublimation (CSS) or sputter techniques in industrial because of in-line production integration. It is seldom reported that CdS is deposited by the chemical bath deposition (CBD) batch process. The bottleneck of CBD for commercial …

Experimental And Modeling Studies In Membrane Distillation, Lin Li

Dissertations

A variety of microporous hydrophobic flat sheet membranes of polyvinylidene fluoride (PVDF) and expanded-polytetrafluoroethylene (e-PTFE) are studied to evaluate the influence of membrane properties on their performance in desalination by direct contact membrane distillation (DCMD) and vacuum membrane distillation (VMD) processes. The membrane thickness is varied between 23 μm to 125 μm; the pore size is varied from 0.05 μm to 0.45 μm. The porosity is generally high in the range of 0.7 - 0.8. DCMD experiments are performed over a hot brine temperature range of 65 °C to 85 °C and distillate temperature at 25 °C for various brine …

Dissolution Kinetics Of Model Api In Molten Polymer Excipients During Batch Processing, Shen Ji

Theses

In the pharmaceutical industrial application field, hot-melt extrusion (HME) has been recently introduced to develop new solid dosage forms and products. By dissolving the poorly–soluble active pharmaceutical ingredients (API) into water-soluble polymers, the bioavailability of the Class II (with low solubility and high permeability in water) API in Biopharmaceutical Classification System (BCS) could be significantly improved in the body. For readily water-soluble API, HME provides a new approach to produce a controlled release drug system. Hence, pharmaceutical HME is a promising processing method in the pharmaceutical industry.

However, HME has not been widely applied into the pharmaceutical industry. The thermal …

Preparation, Ignition And Combustion Of Reactive Metal-Sulfur Nanocomposites, Ziyue Zhong

Theses

Mechanical milling is applied to synthesize reactive metal-sulfur nanocomposites. Specifically, magnesium-sulfur, aluminum-sulfur and zirconium-sulfur nanocomposite powders are prepared. Each powder particle contained homogeneously mixed sulfur and respective metal. These materials are expected to be stable in room air. They are also expected to release sulfur upon ignition; the released sulfur may serve as a biocidal agent. The ignition temperatures of the three prepared sulfur-bearing materials fall in a range of 750 - 1000 K. All prepared materials are successfully ignited in electrostatic discharge experiment as well as in a constant volume explosion experiment. The most sensitive material to spark ignition …

Development And Analysis Of Aluminum-Ptfe Reactive Composite Material, Siva Kumar Valluri

Theses

The shortcomings of micron sized aluminum due to the oxide barrier and two phase loses pose a hindrance for its efficient use as a fuel. In this study a fluoropolymer; Teflon’s inclusion in micron sized -325 mesh aluminum is suggested as a replacement to aluminum. Aluminum Teflon based energetic material see great potential for use in pyrotechnics, propellants and even explosives. A composite with composition Al-PTFE (90-10 wt. %) is prepared through Cryomilling and is shown to be a better method of preparation as compared to room temperature milling. The prepared materials are studied to identify best conditions. The analysis …

Oxidation Kinetics Of Metallic Powders, Hongqi Nie

Dissertations

Aluminum and magnesium are widely used in pyrotechnic formulations and other energetic materials; they are also common components of reactive alloys, e.g., Al-Mg and B-Mg, and others, which are potential fuels for explosives and propellants. Reaction mechanisms and oxidation kinetics of aluminum, magnesium and Al-Mg alloy powders in different oxidizing environments are investigated using thermo-analytical measurements. New methods of data processing are developed, relying on measured particle size distributions of the reactive spherical powders. It became possible to identify the reaction interface location for many heterogeneous metal oxidation processes; for several reactions, detailed kinetic descriptions are obtained.

For aluminum powders, …

Custom Engineered Nanomaterials For Energetics And Energy Applications, Ani Abraham

Dissertations

Recent interest in reactive material has shifted to more custom formulations targeting specific applications. In this work, preparation and characterization of nanomaterials used for several energetics and energy applications are addressed.

The main challenge of this effort is to design and prepare nanomaterials which have significant improvements associated with combustion dynamics, reaction rates, sensitivity, biocidal effectiveness, moisture stability, and are environmentally safer over the existing energetics. Nanomaterials that are used to defeat stockpiles of chemical and biological weapons, modify ionosphere properties for transmission of optical and radio signals, and for energy storage are prepared under room or cryogenic temperatures via …

Laboratory Studies Of The Biodegradation Of Chemically Dispersed Oil: Effect Of Droplet Size And Nutrient Amendment, Christopher D'Ambrose

Dissertations

Oil spills could have devastating effects on the shorelines, and for this reason, chemical dispersants are commonly used to disperse the oil slick in the water column, preventing it from reaching the shorelines. However, the long term fate of dispersed oil depends on its biodegradation by indigenous microorganisms, which in turn depends on the concentration of nutrients in water and on the droplet size distribution.

Using water from the shorelines of Atlantic City, we placed the water with oil and dispersant inside EPA Baffled Flasks and placed them on rotatory shakers. We selected two speeds: high (250 rpm) and low …

Synthesis Of A Renewable Sourced Thermotropic Polyester With 2,5-Furandicarboxylic Acid, Alicia Marie Marguerite Hurst

Theses

With the rapid depletion of non-renewable sourced materials, unpredictable fluctuations in the prices of fossil fuels, and increased environmental awareness the need to develop biobased materials grows ever more desperate. Furan derivatives sourced from hexoses provide a promising solution for replacing petrochemical based materials. One furan derivative in particular, 2,5-furandicarboxylic acid (FDCA), is especially promising due to its structural similarity to terephthalic acid and potential for use in the production of polyesters similar to PET, PPT, and PBT. This study investigated the synthesis, thermal and liquid crystalline properties of a totally renewable sourced thermotropic polyester based on FDCA. Fructose was …

Computational And Experimental Determination Of The Hydrodynamics In A Stirred Unbaffled Vessel Provided With Angle-Mounted Axial Impellers, Ji Ma

Theses

In most industrial applications, stirred tanks and reactors are typically provided with baffles to improve their mixing characteristics. However, in a number of pharmaceutical production facilities unbaffled vessels are commonly used. The absence of baffles is preferred in such cases because it reduces the potential for contamination and makes cleaning the vessel between batches easier. However, the lack of baffles also has a negative impact on the system’s hydrodynamics since it often results in poor mixing of the batch, especially if the impeller is centrally placed, since the liquid in such a system is subject to a strong tangential flow, …

A Preliminary Investigation Of The Sterile-Filterability Of Bcs Class Ii Drug Nanosuspensions Prepared Via Wet Stirred Media Milling, Parul Ohri

Theses

Drug nanoparticles can achieve targeting capabilities, enhanced dissolution rates and improved bioavailability when injected intravenously. Sterile filtration of drug nanoparticle suspensions (nanosuspensions) is critically needed for administration by intravenous delivery route. Avoiding gamma irradiation and high temperatures, sterile filtration could be an effective process to sterilize drug nanosuspensions. On the other hand, two major challenges must be tackled: drug particles must at least be smaller than the filter pore size and minimum amount of non-toxic stabilizers must be used to prevent side effects like pain on the injection site. The aim of this study is to prepare naproxen (NPX) nanosuspensions …

Hydrodynamics, Dissolution, And Mass Transfer Effects In Different Dissolution Testing Apparatuses And Laboratory Systems, Bing Wang

Dissertations

Dissolution testing apparatuses and shaker flasks agitated by shaker tables are laboratory systems routinely found in many laboratories at most companies and agencies, and especially in pharmaceutical companies. These devices are commonly used in a number of applications, from drug development to quality control. Despite their common use, these systems have not been fully investigated from an engineering perspective in order to understand their operation characteristics. For example, the hydrodynamics of many of these systems have received little attention until relatively recently, and only over the last few years have some of these systems, such as the USP dissolution testing …

Principles And Applications Of Mechanical Dry Coating - Review And State-Of-The-Art, Sayani Bhaumik

Theses

Dry Coating of powders to form composite particulates has been firmly established and has garnered interest both in academia and industry due to its myriad applications. This thesis work is an attempt to map the progress of the dry coating technology from its incipient years in the '80s to the thriving practice in the present day. Dry coating is a relatively simple approach to coat powders with specific guest particles via mechanical means to produce composites with desired tailor-made properties, without the constraints of harmful emissions or huge capital investment. Composite particulates with enhanced flowability, high-temperature resistant properties, and modified …

The Kinetics Of Drug Dissolution In Polymers During Hot-Melt Extrusion, Huayang Fang

Theses

Extrusion has been a most important and widely used continuous process in polymer processing for over one hundred and fifty years. However, it has only been recently applied and adopted by the pharmaceutical industry to prepare solid oral dosage formulations with increased bioavailability for the poorly-water soluble drugs and controlled release characteristics for the water-soluble drugs. In pharmaceutical Hot-melt extrusion poorly water soluble drug particulates are mixed with water soluble polymer excipient particulates and fed in the extruder, where the polymer is melted, after which the drug particulates begin to dissolve into the polymer melt. Extrusion-generated mixing accelerates dissolution process. …

Experimental Determination Of The Agitation Requirements For Solids Suspension In Dissolution Systems Using A Mini Paddle Apparatus, Yang Song

Theses

Dissolution testing is a critical step in quality control of manufactured final products in the pharmaceutical industry. The United State Pharmacopeia (USP) Dissolution Testing Apparatus 2 (paddle) is the most widely used dissolution test devices in the pharmaceutical industry to formulate solid drug dosage forms and to develop quality control specifications for its manufacturing process.

Mini vessels and mini paddle dissolution testing systems are smaller versions of the USP 2 Apparatus. The concept of the mini paddle apparatus is similar to that of the USP 2 setup but it is scaled down about to 1/5 of the volume and 40% …

Effect Of Impeller Submergence On Power Dissipation And Solids Suspension In Mixing Systems Equipped With Pitch-Blade Turbines, Yufeng Song

Theses

Mixing and dispersion of solids in a liquid is a process frequently encountered in the pharmaceutical industry and often conducted in cylindrical baffled tanks stirred by mechanical impellers. In operations where the liquid level is decreased (as often which emptying the tank) the process must be stopped when the solids are no longer suspended. In this work, the minimum agitation to suspend solids (Njs) when the liquid level was lowered, and the impeller submergence S_b changed as a result were determined for the case of a six-blade, pitch-blade turbine (6-PBT) impeller. The power consumed by the impeller …

Experimental Determination Of Solids Suspension With Angled Impeller In A Pharmaceutical Mixing Vessel, Yingxi Tang

Theses

Angled-mounted impellers are commonly used in a number of pharmaceutical industry applications, from laboratory reactors to full-scale tanks. In these systems, the impeller is not centrally and vertically mounted, as in most stirred vessels, but it enters the vessel, and is therefore immersed in the fluid, at an angle from the vertical. This arrangement provides some baffling effects that would not otherwise exist if the impeller was centrally mounted.

One common requirement for such systems is that they are capable of suspending small solids dispersed in the liquid. Therefore, it is critical to know the value of the minimum agitation …