Engineering Commons^™

Theoretical Prediction Of Drug Release In Gi Tract From Spherical Matrix Systems, Naga Lakshmi Ramana Susarla

Dissertations

The significance of controlled release drug delivery systems (CRDDS) lies in their ability to deliver the drug at a steady rate thus reducing the dosage interval and providing a prolonged pharmacodynamic effect. But despite the steadily increasing practical importance of these devices, little is known regarding their underlying drug release mechanisms. Mathematical modeling of these drug delivery systems could help us understand the underlying mass transport mechanisms involved in the control of drug release. Mathematical modeling also plays an important role in providing us with valuable information such as the amount of drug released during a certain period of time …

Effects Of Operating And Geometric Variables On Hydrodynamics And Tablet Dissolution In Standard And Modified Dissolution Testing Apparatuses 2, Yimin Wang

Dissertations

Dissolution testing is routinely conducted in the pharmaceutical industry to provide critical in vitro drug release information for quality control purposes, and especially to assess batch-to-batch consistency of solid oral dosage forms such as tablets. Among the different types of apparatuses listed in the United States Pharmacopoeia (USP), the most commonly used dissolution system for solid dosage forms is the USP Dissolution Testing Apparatus 2, consisting of an unbaffled, hemispherical-bottomed vessel equipped with a 2-blade radial impeller.

Despite its extensive use in industry and a large body of work, some key aspects of the hydrodynamics of Apparatus 2 have received …

Multifunctional Reactive Nanocomposite Materials, Demitrios Stamatis

Dissertations

Many multifunctional nanocomposite materials have been developed for use in propellants, explosives, pyrotechnics, and reactive structures. These materials exhibit high reaction rates due to their developed reaction interfacial area. Two applications addressed in this work include nanocomposite powders prepared by arrested reactive milling (ARM) for burn rate modifiers and reactive structures. In burn rate modifiers, addition of reactive nanocomposite powders to aluminized propellants increases the burn rate of aluminum and thus the overall reaction rate of an energetic formulation. Replacing only a small fraction of aluminum by 8Al•MoO₃ and 2B•Ti nanocomposite powders enhances the reaction rate with little change …

Effect Of Dry Particle Coating On The Properties Of Cohesive Pharmaceutical Powders, Lauren Elizabeth Beach

Dissertations

Engineered particles, which have undergone surface modification via dry coating, have been previously shown to have improved flow and handling properties. The improvements in these properties can be applied and are very useful for a number of industrial applications, in this case the pharmaceutical industry. This work investigates the effect of dry particle coating to improve the flowability of cohesive active pharmaceutical ingredient (API) powders and their blends. Improving the flow properties of cohesive API powders can significantly improve their handling and subsequent use for pharmaceutical processes such as formulation and manufacturing processing operations. Although it has been shown that …

Electrodeless Electro Hydrodynamic Printing Of Personalized Drug Dosages, Ezinwa Okeoma Elele

Dissertations

There is compelling evidence that variability in drug efficacy in individuals depends on their genetic fingerprints. These observations have given rise to the concept of personalized therapy whose ultimate goal is to develop medicinal agents designed for each niche of the population and individual patients according to their genetic background. The drawback in current pharmaceutical technologies is that most processes are designed to target large population and are unable to meet the demand of small-scale manufacturing of tailored therapeutics with diverse range of physical properties. One of the major challenges lie in developing efficient and cost effective methods of manufacturing …

Deagglomeration And Mixing Via The Rapid Expansion Of High Pressure And Supercritical Suspensions, Daniel To

Dissertations

Nano-materials are the focus of many research activities due to the desirable properties imparted from their small grain size and high interfacial surface area. However, these materials are highly cohesive powders in the dry state and typically form large agglomerates, leading to a diminished surface area or even grain growth, which minimizes the effectiveness of these nanomaterials. This dissertation addresses the issue of mixing nanopowders constituents by deagglomerating them and achieving simultaneous mixing so that even after inevitable reagglomeration, the effectiveness of large interfacial surface area may be preserved.

Nano-particle mixtures were prepared using the environmentally benign dry mixing methods …

Study Of The Heating And Ignition Of Metal Powder By Electrostatic Discharge, Ervin Beloni

Dissertations

The objective of this work was to understand the processes that lead to ESD stimulated ignition events in metal powders. Several metals were studied: Mg, Al, and Ti. A commercially available ESD test device was adapted for the present experiments. The ESD current and voltage were measured using inductance coils; the data were used to determine the electric circuit impedance, and energy transferred to the powder. A mode of the powder ignition (individual particles vs. dust cloud), ignition delays, burn times, and velocities of ignited and ejected particles were determined from optical measurements.

It was determined that the ESD energy …

Transdermal And Transbuccal Delivery Of Lidocaine And Nicotine : Combined Effects Of Iontophoresis And Chemical Enhancers, Ran Wei

Theses

This study focused on the effects of iontophoresis and chemical enhancers on drug release. The transport of Lidocaine HCl (LHCl) and Nicotine Hydrogen Tartrate (NHT) through the skin and mucosa was evaluated for potential clinical applications. These two potential delivery routes have the advantage of avoiding first-pass effect. Samples were pretreated with enhancer solutions for one hour before the experiments. Passive or 0.3 mA iontophoresis-assisted drug diffusion was conducted for 8 hours to monitor the cumulative amount of drug released. Graphical methods and mathematical optimization techniques were implemented to analyze the data. The effects of chemical enhancers on the delivery …

Investigation Of The Potential Catalytic Activities Of Several Metal Organic Framework (Mof) Materials, Guangyu Zhang

Theses

Metal-organic frameworks (MOFs) are promising porous materials due to their high porosities, large apparent surface areas, tunable pore properties and selective uptake of small molecules. Many researches have been focused on developing new MOF structures and exploring their use in gas storage and separation. Only few studies investigated the catalytic properties of MOFs. In this study, catalytic properties are explored over several MOFs including zeolitic imidazolate framework-8 (ZIF-8), Ni(FA) and Zn(FA). These MOFs are used as catalyst supports for iron or platinum nanoparticles. The catalysts are prepared using incipient wetness impregnation method and characterized with Brunauer-Emmett-Teller (BET), pulse chemisorption, X-ray …

Dissolution Of Disintegrating Solid Dosage Forms In A Modified Dissolution Testing Apparatus 2, Shrutiben Rameshbhai Parekh

Theses

Dissolution tests are routinely carried out in the pharmaceutical industry to determine the dissolution rate of solid dosage forms. Dissolution testing serves as a surrogate for drug bioavailability through in vitro–in vivo correlation (IVIVR), and it additionally helps in guiding the development of new formulations and in assessing lot-to-lot consistency, thus ensuring product quality. The United States Pharmacopoeia (USP) Dissolution Testing Apparatus 2 is the device most commonly used for this purpose. Despite its widespread use, dissolution testing using this apparatus remains susceptible to significant error and test failures. There is documented evidence that this apparatus is sensitive to several …

Thermochemical Properties, Bond Energies And Internal Rotor Potentials In Methyl Ethyl Sulfide And Oxygenated Sulfur Hydrocarbons Intermediates For Modeling Its Combustion And Atmospheric Chemistry, Guanghui Song

Theses

Small (1 to 4 carbon) hydrocarbon sulfides and thiols are formed in the biosphere by microorganisms and subsequently emitted into the lithosphere, hydrosphere and atmosphere. In the atmosphere they are oxidized by photochemical and radical reactions to intermediate hydrocarbon and to sulfur oxides. The oxides of these sulfur compounds and the intermediates from the oxidation process are known to form aerosols that can counteract the global warming green house effect. Recent studies also suggest that some aerosols can also contribute to global warming. Sulfur oxides are also major contributors to acid rain as the results of the atmospheric chemistry oxidation …

Dissolution Testing Of Prednisone And Salicylic Acid Calibrator Tablets At Different Tablet Locations, Anandhavalavan Arulmozhi

Theses

Dissolution testing is routinely carried out in the pharmaceutical industry to determine the rate of dissolution of solid dosage forms. This test is one of the several tests that pharmaceutical companies typically conduct on oral dosage formulations (e.g., tablets) to determine compliance. The USP Dissolution Testing Apparatus 2 is the most common of the apparatuses listed in the USP. However, it has been shown previously that the dissolution profile of a tablet undergoing dissolution in the USP Dissolution Apparatus 2 can be affected by the tablet location in the apparatus.

In this work, the dissolution rates of both non-disintegrating tablets …

Study Of Controlled Release Of Active Pharmaceutical Ingredients From Functionalized Nanoclays And Polymer Matrices, Jin Uk Ha

Dissertations

This dissertation contains the results of three related novel investigations in the field of structure-property-processing relationships of pharmaceutical polymer-based products. They are: a) modification of a pharmaceutical anionic nanoclay with two different Active Pharmaceutical Ingredients (APIs) to produce nanohybrid API carriers intended to be used alone or in acrylic polymer matrices, b) comparison of binary systems containing the above APIs in the selected acrylic polymers in terms of their miscibilities with the polymer, but in the absence of nanoclay, and c) comparison of the polymer/API binary systems with ternary polymer/API/Clay systems.

For the first study, the calcination method which can …

Study Of Controlled Release Of Dapsone From Modified Montmorillonite And Polymer Matrices, Jia Fan

Theses

This thesis focuses on the controlled release system of Dapsone (DAP) as the Active Pharmaceutical Ingredient (API) intercalated into sodium montmorillonite (MMT-Na+) and their combination with an anionic copolymer (Eudragit® S100). The effects of the excipients on the API dissolution rate were studied from their release profile in simulated intestinal fluid (pH=7.4) at 37±0.5°C. In the first part of the research, ionizable Dapsone was intercalated in the interlayers of MMT-Na+ to produce a nanohybrid. In the second part of the research, the nanohybrid was melt dispersed in the polymer to produce ternary (API/ Clay/ Polymer) composites. For comparison, API-polymer solid …