Engineering Commons^™

Dissolution Of Different Commercial Aspirin Tablets Using A Novel Off-Center Paddle Impeller (Opi) Dissolution Testing System, Yang Qu

Theses

Dissolution testing is routinely conducted in the pharmaceutical industry to provide in vitro drug release information for quality control purposes. The most common dissolution testing system for solid dosage forms is the United States Pharmacopeia (USP) Dissolution Testing Apparatus 2. In this work, a modified Apparatus 2, termed "OPI" System for "off-center paddle impeller," in which the impeller is placed 8 mm off center in the vessel is tested to determine its sensitivity to differentiate between the dissolution profiles of differently formulated and manufactured tablets. Dissolution tests are conducted with both the OPI System and the Standard System using three …

Qsar Modeling Of Chemical Penetration Enhancers Using Novel Replacement Algorithms, Hui Qiu

Theses

The applications of transdermal delivery are limited because of the resistance of the skin to drug diffusion. Only potent drugs, with molecular weight less than 500 Da, are suitable to cross the skin barrier. Chemical Penetration Enhancers (CPEs) are used to promote the absorption of solutes across the dermal layers. In this investigation, a Quantitative Structure-Activity Relationship (QSAR) model is applied to relate chemical penetration enhancer structures with the flux enhancement ratio through a statistical approach.

A database, consisting of 61 non-polar CPEs, is selected for the study. Each compound is represented by 777 QSAR descriptors, which encode the physical …

Engineering Spores To Display G Protein-Coupled Receptors For Directed Evolution, Alyssa Misoo Kim

Theses

All human cells are surrounded by a plasma membrane made from a phospholipid bilayer, which is responsible for maintaining a biologically active species, while stopping entry of deleterious substances from the outside. G protein-coupled receptors (GPCRs) are the membrane proteins, which transmit signals across the cell membrane. GPCRs are involved in almost every physiological process, and irregular control leads to pathological conditions. Therefore, they are major drug targets. Crystal structure determination is required to understand the molecular details of activation/deactivation. However, GPCRs are difficult to crystallize because of stability issues. An efficient protein engineering system needs to be developed. The …

Hollow Fiber Membrane-Based Air Gap Membrane Distillation, Xuan Wang

Theses

Membrane Distillation (MD) is a thermally-driven separation process. In this research, desalination of 1 % NaCl solution is achieved by one type of MD namely, Air Gap Membrane Distillation (AGMD). The characteristics of AGMD are evaluated by using a hollow-fiber-set-based compact device. Hot brine solution and cold water are passed through two different fiber sets separately: porous hydrophobic polyvinylidene fluoride hollow fibers of the E type (PVDF E) and solid polypropylene (PP) hollow fibers. Vapor from the hot brine crosses the membrane pores of the PVDF fibers and the air gap, and finally condenses over the surface of solid hollow …

Effect Of Tablet Compression On The Dissolution Of Aspirin Tablets Using A Novel Off-Center Paddle Impeller (Opi) Dissolution Testing System, Chuan Sun

Theses

In the pharmaceutical industry, dissolution testing is routinely carried out to determine the dissolution rate of oral solid dosage forms. Among several testing devices, the USP Dissolution Apparatus 2 is the device most commonly used. However, despite its widespread use, this apparatus has been shown to produce test failures and to be very sensitive to a number of small geometry changes.

The objective of this study was to determine whether a novel dissolution system termed “OPI” for “off-center paddle impeller” was sensitive enough to determine differences in tablet dissolution profiles caused by different compression pressure during the tablet manufacturing process. …

Hydrodynamic Effects Of A Cannula In A Usp Dissolution Testing Apparatus 2, Qianqian Liu

Theses

Dissolution testing is routinely used in the pharmaceutical industry to provide in vitro drug release information for drug development and quality control purposes. The USP Testing Apparatus 2 is the most common dissolution testing system for solid dosage forms. Usually, sampling cannulas are used to take samples manually from the dissolution medium. However, the inserted cannula can alter the normal fluid flow within the vessel and produce different dissolution testing results.

The hydrodynamic effects introduced by a permanently inserted cannula in a USP Dissolution Testing Apparatus 2 were evaluated by two approaches. Firstly, the dissolution tests were conducted with two …

Hydrodynamic Effects Of An Arch-Shaped Fiber Optic Probe In A Dissolution Testing Apparatus 2, Yiran Zhang

Theses

Dissolution testing is widely used in the pharmaceutical industry to evaluate newly developed drug formulations and as a quality control method to insure that solid dosage forms have consistent dissolution property. Typically, samples are manually drawn from the dissolution vessel prior to analysis. An approach to overcome the limitations of manual sampling consists in the use of sampling probes, such as fiber optic probes, permanently inserted in the dissolution medium and continually sampling the drug concentration in it as the solid dosage form dissolves. Despite their advantages, permanently inserted fiber optic probes can alter the normal fluid flow within the …

Preparation Of Different Polyamide Nanofiltration Membranes By Interfacial Polymerization And The Effect Of Post-Polymerization Treatment On Separation Performance, Yu Qin

Theses

Interfacial polymerization (IP) is a powerful technique for fabrication of thin film composite (TFC) membranes. In this study, polyamide nanofiltration (NF) composite membranes ware prepared by interfacial polymerization of polyethylenimine (PEI) or m-phenylene diamine (MPD) with isophthaloyl dichloride (IPD) on the surface of a porous polyethersulfone (PES) support. Concentrations of monomer reactants for this reaction were decided by equivalent weight ratio. A standard IP procedure was applied to successfully coat PES flat films. After preparation, three different post-polymerization treatments were employed and one optimal treatment was proven after membrane testing.

The TFC flat film membranes were characterized by nanofiltration of …

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 …

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 …

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 …

Minimum Agitation Speed For Solid Suspension And Mixing Time In A Torispherical -Bottomed Pharmaceutical Stirred Tank Under Different Baffling Conditions, Dilanji Bhagya Wijayasekara

Theses

The minimum agitation speed, NS, required to just suspend solid particles dispersed in water was experimentally determined in this work for a glass-lined type of mixing tank provided with a torispherical bottom and agitated with a retreat-blade impeller under different baffling configurations. Ns for the same tank but equipped with a different agitation system, namely an axial impeller, was also experimentally determined for the purpose of comparing of performances of the two systems. The effect of impeller off- bottom clearance and the vessel's liquid level on the minimum agitation speed were also experimentally studied. Njs, was experimentally determined …

Experimental Investigation Of Mixing Time In A Stirred, Torispherical-Bottomed Tank Equipped With A Retreat-Blade Impeller, Nonjaros Chomcharn

Theses

Glass-lined reactors are typically used in the pharmaceutical and specialty chemicals industries because of their material compatibility with most reactants and their cleanability. These reactors are typically equipped with a retreat-blade impeller placed close to the bottom of the tank a single baffle mounted from the top. The mixing performance of such reactors has not received significant attention in the literature, despite their ubiquitous presence in the pharmaceutical industry. In particular, mixing time, i.e., the time required by the system to achieve a predefined level of homogeneity, has not been studied to any significant degree.

In this work, the mixing …

Mixing Performance Of A Novel, Continuous Confined Impinging Jets Mixer Using Competitive Reactions, Han Zheng

Theses

In this work, a novel continuous flow apparatus featuring the impingement of fluid jet streams in the presence of ultrasonic energy provided by an ultrasonic probe was tested using competitive reactions in order to determine its mixing effectiveness. The ultrasonic energy enhances micromixing of the fluid jet streams, which results in an overall mixing effectiveness improvements in different physical and chemical processes.

In the competitive reactions system used here (third Bourne reaction), one stream containing sodium hydroxide was continuously fed to the first impinging jet, while an aqueous solution of hydrochloric acid and ethyl chloroacetate was fed to the second …

Preparation Of Nanovehicles For Targeted Drug Delivery, Anagha Avinash Bhakay

Theses

Application of nanotechnology in pharmaceutical research has opened new frontiers for drug development and its efficient delivery. In recent years, the focus of the research has been on the engineering of nano/micro-particulate structures for efficient and targeted delivery of drugs for selective and enhanced absorption. This work throws light on the preparation of biodegradable and non-toxic nanoparticulate systems for targeted drug delivery. The drug vehicles were made by two different processes namely electrostatic interactions and desolvation process. The drug carriers made by these processes were found to be in the size range of 150-200nm which is necessary for cellular uptake …

Experimental Investigation Of The Fluid Velocity Distribution In Stirred Tank Reactors Equipped With Retreat-Blade Impellers Using Laser Doppler Velocimetry, Deepak Rajesh Madhrani

Theses

Stirred tank reactors are commonly used in the pharmaceutical industry for synthesis of Active Pharmaceutical Ingredients (API's) and their intermediates. Typically, these vessels are glass-lined and are provided with a single retreat-blade glass-lined impeller and a single baffle. Despite their ubiquitous utilization in the pharmaceutical industry for at least the past 40 years, the mixing characteristics of these systems have not been studied to any great extent, making it difficult to predict mixing performance in any given operation.

In this work, the velocity distribution inside the typical glass-lined vessel/impeller system was experimentally quantified using Laser Doppler Velocimetry (LDV), which is …

Ultra-Fine Particle Formation Using Principle Of Rapid Expansion Of Supercritical Solutions`, Miraj Minesh Sheth

Theses

There are indications in the chemical and pharmaceutical industries that the reduction in size of a crystalline particle can lead to better performance of the drug compound, particularly for water insoluble drugs, in the final dosage form. Many particle formation techniques have been investigated in recent years by researchers to obtain desired particulate sizes and size distributions. Supercritical fluid technologies have been successfully investigated for particle formation due to its unique gas/liquid properties in the supereritical state. In this report, results of particle formation using the principles of Rapid Expansion of Supercritical Solutions (RESS) have been documented.

In the RESS …

Mathematical Modeling Of Transient State Transdermal Drug Delivery, Alison Nickol Weltner

Theses

In this work, a two-pathway mathematical model for transdermal drug delivery with iontophoresis is presented. The partial differential equations are described and then solved. An alternative, two-pathway, three-layer model is also presented, and the implications of the coefficients within the equation are discussed. Using Franz cell iontophoretic delivery data from three drug substances (amitriptyline HCl, clomipramine HCl, and nortriptyline HCl), the two-pathway model is regressed to determine the diffusion coefficient and the concentration within the skin at the drug reservoir interface. ANOVA analysis indicates a correlation between iontophoretic current and concentration of drug within the stratum corneum.