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Computerized formulation and optimization of medicated chewing gumBerky, Daniel J. 01 January 1984 (has links) (PDF)
Sixty Four caffeinated chewing gum preparations were formulated by varying the amounts of (i) cinnamaldhyde, (0-0.75%), (ii) docusate (0-0.5%) and (iii) sucrose (40-60%). The gum base consisted of 33.33% yellow beeswax and 66.66% polyisobutylene MH, and was added, adjusting for a final weight of 2 grams per gum. The amount of caffeine was maintained at 100mg. The preparations were subjected to an in vivo release study as well as a hedonic survey with a panel of student volunteers.
Data were analyzed by using multiple linear regression on a mainframe computer. The resulting mathematical model was used to predict a theoretically ideal formulation, relating various concentrations of the above constituents to a global rating. The results indicated consistent release (90-100%) of caffeine for most formulations, but considerable variation was observed for the hedonic scores. A positive correlation with cinnamaldehyde and flavor was observed, while increased amounts of sugar appeared to lower the overall rating. The optimum formulation predicted by the model should contain 40% sucrose, 0.5% docusate and 0.75% cinnamaldehyde.
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Structure Pharmaceutics Based on Synchrotron Radiation X-Ray Micro- Computed Tomography: From Characterization to Evaluation and Innovation of Pharmaceutical StructuresYin, Xianzhen January 2016 (has links)
Drug delivery systems (DDS) are essentially pharmaceutical products for human
therapy, typically involving a mixture of active ingredients and excipients. Based
upon quantitative characterization of structure, the thesis introduces the concept
of classifying the architecture of DDS into four levels by their spatial scale and
the life time period. The primary level is recognised as the static structure of the
whole dosage form with a size from μm to cm with the final structure generated
by formulation design. The secondary level categorises the structures of particles
or sub-units to form a DDS with sizes from nm to mm as key units in processing
such as mixing, grinding, granulation and packing; The tertiary level represents
the dynamic structures of DDS during the drug release phase in vitro or in vivo
incorporating the structure size range from nm to mm, which undergo changes
during dissolution, swelling, erosion or diffusion. The spatial scale for the
quaternary level is defined as the meso or micro scale architecture of active and
non-active molecules within a DDS with sizes from Å to μm for the molecular
structure of drug and excipients.
Methods combining X-ray tomography, image processing, and 3D
reconstructions have been devised and evaluated to study systematically
pharmaceutical structures and correlate them with drug release kinetics of DDS.
Based on the quantitative structural information of pharmaceutical intermediates
and dosage forms, it is possible now to correlate structures with production
processing, behaviour and function, and the static and dynamic structures of DDS
with the release kinetics. Thus, a structure-guided methodology has been
established for the research of DDS. / Chinese Academy of Sciences
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Development of a novel gastro-retentive delivery system using alfuzosin HCl as a model drugLiu, Quan. January 2010 (has links)
The objectives of this project encompass the design and development of a drug delivery system to continuously deliver therapeutic agents from the stomach to the proximal region of the intestine. The delivery system designed would have sufficient gastric residence time together with near zero-order release kinetics. The physicochemical properties pertaining to the formulation development of the model drug (alfuzosin HCl) were evaluated. Excipients were selected based on the studies of their physicochemical properties and compatibility with the active ingredient. Gastro-retentive dosage forms have been the topic of interest in recent years as a practical approach in drug deliveries to the upper GI tract or for release prolongation and absorption. These dosage forms are particularly suitable for drugs that have local effects on the gastric mucosa in the stomach. Other candidates include drugs that are likely to be absorbed in the upper small intestine, or drugs that are unstable in basic environment of distal intestine and colon or those with low solubility at elevated pH conditions (i.e. weak bases). To develop a gastro-retentive delivery system the following steps were taken. First, to investigate the possible incompatibility issues between the model drug and excipients to be used for the delivery system. Stability and physicochemical properties of the active agent and its mixture with excipients were studied using analytical techniques such as Raman spectroscopy and Differential scanning calorimetry (DSC). No incompatibility issues were detected. Second, Kollidon SR as a relatively new release-rate controlling polymer was incorporated in the final formulation. For solid dosage form the ability of the final powder mix to flow well during manufacturing and the intrinsic characteristics that make it compressible are critical. The in-depth compaction study of Kollidon SR was assessed with the help of a compaction simulator. The flowability, swelling and erosion behavior together with release-rate retarding properties of Kollidon SR were also assessed. The final oral delivery system was based on Kollidon SR and Polyethylene Oxide (PEO) 303 as a monolithic matrix system. The noneffervescent monolithic matrix was made by direct compression. In vitro evaluation of the designed system released the active content in a near zero manner. The dosage form was bouyant in pH 2.0 acidic buffer with no floatation lag time which minimizes the possibility of early gastric emptying. / Pharmaceutics
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Developing a process analytical technology for monitoring the particle size distribution in twin screw granulationAbdulhussain, Hassan January 2024 (has links)
Twin screw wet granulation (TSG) has been studied as a continuous manufacturing alternative to batch granulation for nearly twenty years. One of the main differences between batch granulation and TSG lies in the exiting granules being presented as a bimodal particle size distribution (PSD) in the latter case. Current process analytical technologies (PAT) can monitor a monomodal distribution well but there have been no techniques disclosed in the public domain so far that can accurately monitor this unusually shaped PSD. Acoustic emissions (AE) has been identified as a PAT of interest due to its ease of use (lack of calibration), low cost, and non-invasive design relative to other PATs used for monitoring PSDs. Hence the goal of this thesis was to develop AE as a process analytical technology (PAT) capable of estimating the full distribution of produced granules by TSG in real time.
The first research study of this thesis focused on the development of the new technology. The AE PAT consisted of an acoustic sensor, an impact plate, and software to convert the time-domain signal of particle collisions into a time-averaged frequency-domain spectrum to be subsequently used to estimate a weight-averaged particle size distribution. A novel and much required addition to the PAT was inclusion of a digital filter based on particle mechanics parameters to overcome auditory masking which hindered accurately converting the cumulative sounds of impact into a PSD. The PAT was tested in this study with granulated lactose monohydrate and with the new digital filter, obtaining a maximum error of 1 wt% across all particle sizes tested. In the second research study, as more formulations commonly used in the industry were tested, the filter proved unable by itself to account for the differences in impact mechanics and therefore needed to be modified to incorporate the more inelastic behaviour now being seen. Two micromechanical models were explored, and the Walton-and-Braun model was found to be the most suitable for the AE PAT – reducing its error from 8 wt% down to 2.75 wt% across four formulations producing coefficients of restitution from 0.79 to 0.24.
In the last research study in this thesis, the now-functional inline PAT was used to reveal mechanistic details related to the transition state in granulation as a TSG starts up, to improve the field’s understanding of the granulation mechanism. The technique was able to estimate the PSD over much shorter periods of material collection compared to sieving, allowing the evolution of the PSD as a function of time to be examined for varying degrees of fill (DF) and liquid-to-solids ratios. It was determined that the time to steady state, at both DF tested, occurred at approximately 5 times the mean residence time of the process by both PAT and sieving analyses. Particle sizes between 102-2230 μm were then tracked as a function of time below 120 s and variations of granule growth were seen for each degree of fill which added to the understanding of the granulation mechanism. This PAT shows great promise as a monitoring tool to implement quality by design principles for TSG in pharmaceutical manufacturing. / Thesis / Doctor of Philosophy (PhD)
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SELECTIVE FORCES SHAPING DUPLICATE GENE EVOLUTION: INSIGHTS FROM STOCHASTIC MODELING AND PATTERNS OF RETENTIONWilson, Amanda, 0000-0002-4711-377X 05 1900 (has links)
The variation of genome content and structure across the tree of life is astounding and can provide clues to understand the process of evolution. Overall, this helps us understand the history of life and how organisms have fundamentally changed and adapted to their environments. Gene duplication is an important mechanism for molecular evolution because it provides opportunity for functional novelty and molecular innovation. Gene duplication creates new functional gene copies with different selective pressures that allow them to take on new or specialized functions. Throughout this work, I explored the interplay between genetic changes, molecular phenotype, and the selection of duplicate gene copies. I particularly focused on the genetic opportunity, consequences, and selective pressures of the mechanisms for short-term and long-term duplicate copy retention. I modeled the stochastic processes of mutation and selection and their effect on duplicate gene copy retention. Specifically, I modeled the interplay between subfunctionalization and dosage balance and found that selection may cause genes that are sensitive to dosage balance effects to experience delayed subfunctionalization, but ultimately lead to higher levels of subfunctionalization. These findings suggest that subfunctionalization may not occur as a purely neutral process. Next, I used survival analysis methods to model patterns of duplicate gene retention in genomes experiencing consecutive whole genome duplication events. I modeled three hypotheses to explain patterns of duplicate gene retention including the Independence Hypothesis, the Gene Duplicability Hypothesis, and a novel Mutational Opportunity Hypothesis. Under the Gene Duplicability and Mutational Opportunity hypotheses, the expected patterns of duplicate gene retention after consecutive whole genome duplication events are greatly affected by the ages of the whole genome duplication events and the functional properties of the genomic content that influence opportunity and selection. Additionally, I describe how statistical model testing techniques can be applied to investigate which hypothesis is consistent with patterns of retention in real-world phylogenetic datasets. I used these described techniques to explore the hypotheses’ parameter space consistent with a modest dataset of fish and plant lineages. These results suggest that a gene duplicate’s retention after whole genome duplication events may be influenced by its functional properties. Key findings underscore the multifaceted nature of duplicate gene retention, influenced by a myriad of factors including genetic opportunity, selective pressures, and evolutionary context. By dissecting the underlying mechanisms driving duplicate gene retention, this dissertation advances our understanding of the evolutionary dynamics shaping genome evolution and functional diversity across diverse biological systems. / Biology
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Dosage optimization and bolted connections for UHPFRC tiesCamacho Torregrosa, Esteban Efraím 07 January 2014 (has links)
Concrete technology has been in changeful evolution since the Roman Empire time. It is remarkable
that the technological progress became of higher magnitude from the second part of the XX Century.
Advances in the development of new cements, the appearance of the fibers as a reinforcement for
structural applications, and specially the grand progress in the field of the water reducing admixtures
enabled the emergence of several types of special concretes. One of the lasts is the Ultra High
Performance Fiber Reinforced Concrete (UHPFRC), which incorporates advances of the Self-Compacting
Concrete (SCC), Fiber-Reinforced Concrete (FRC) and Ultra High Strength Concrete (UHSC) technology.
This exclusive material requires a detailed analysis of the components compatibility and a high control
of the materials and processes. Mainly patented products have been used for the few structural elements
carried out so far today, but the costs makes doubtful the development of many other potential
applications.
In accordance with the previously explained, a simplification of the UHPFRC components and
processes is needed. This becomes the first main goal of this Ph.D. thesis, which emphasizes in the use
of local available components and simpler mixing processes. Moreover, the singular properties of this
material, between ordinary concrete and steel, allow not only the realization of slenderer structures, but
also the viability of new concepts unthinkable with ordinary concrete. In this field is focused the second
part of the Ph.D. thesis, which develops a bolted connection system between UHPFRC elements.
This research summarizes, first of all, the subfamilies belonging to the HPC-UHPC materials.
Afterwards, it is provided a detailed comparison between the dosage and properties of more than a
hundred of mixtures proposed by several authors in the last ten years of technology. This becomes a
useful tool to recognize correlations between dosages and properties and validate or no preconceived
ideas about this material.
Based on this state of art analysis was performed the later development of mixtures, on Chapter 4,
which analized the effect of use of simpler components and processes on the UHPFRC. The main idea
was use local components available in the Spanish market, identifying the combinations that provide
the best rheological and mechanical properties. Steam curing use was avoided since a process
simplification is intended. Diferent dosages were developed to be adapted to various levels of
performance, and always trying to be as economical as possible. The concretes designed were
selfcompacting and mainly combined two fiber types (hybrid), as the flexural performance was of
greater relevance. The compressive strength obtained varied in the range between 100 and 170 MPa
(cube L=100 mm), and the flexural strength between 15 and 45 MPa (prism 100 x 100 x 500 mm). Some
of the components introduced are very rarely used in UHPFRC, as limestone coarse aggregate or FC3R,
a white active residue from the petrol industry. As a result of the research, some simple and practical
tips are provided for designers of UHPFRC dosage. At the end of this chapter, five dosages are
characterized as examples of useful concretes for different requirement applications. In a second part, the idea of a bolted joint connection between UHPFRC elements was proposed. The
connection system would be especially useful for struts and ties elements, as truss structures. The
possible UHPFRC failure modes were introduced and two different types of tests were designed and
performed to evaluate the joint capacity. The geometry of the UHPFRC elements was modified in order
to correlate it with the failure mode and maximum load reached. Also a linear finite element analysis
was performed to analyze the UHPFRC elements connection. This supported the results of the
experimental tests to deduce formulations that predict the maximum load for each failure mode. Finally,
a real size truss structure was assembled with bolted joints and tested to verify the good structural
behavior of these connections.
To conclude, some applications designed and developed at the Universitat Politècnica de València
with the methods and knowledge acquired on UHPFRC are abstracted. In many of them the material was
mixed and poured in a traditional precast concrete company, providing adequate rheological and
mechanical results. This showed the viability of simpler UHPFRC technology enabling some of the first
applications in Spain with this material. / Camacho Torregrosa, EE. (2013). Dosage optimization and bolted connections for UHPFRC ties [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34790
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Genomic Instability and Gene Dosage Obscures Clues to Virulence Mechanisms of F. tularensis speciesModise, Thero 06 September 2016 (has links)
The pathogen Francisella tularensis subsp. tularensis has been classified as a Center for Disease Control (CDC) select agent. However, little is still known of what makes the bacteria cause dis-ease, especially the highly virulent type A1 strains. The work in this dissertation focused on type A1 strains from the Inzana laboratory, including a wildtype virulent strain TI0902, an avirulent chemical mutant strain TIGB03 with a Single Nucleotide Polymorphism in the wbtK gene, and several complemented mutants, [wbtK+]TIGB03, with dramatic differences in virulence and growth rates. One of the complemented clones (Clone12 or avp-[wbtK+]TIGB03-C12) was aviru-lent, but protected mice against challenge of a lethal dose of TI0902 and was considered as a possible vaccine strain.
Whole genome sequencing was performed to identify genetic differences between the virulent, avirulent and protective strains using both Roche/454 and Illumina next-generation sequencing technologies. Additionally, RNASeq analysis was performed to identify differentially expressed genes between the different strains. This comprehensive genomic analysis revealed the critical role of transposable elements in inducing genomic instability resulting in large du-plications and deletions in the genomes of the chemical mutant and the complemented clones that in turn affect gene dosage and expression of genes known to regulate virulence. For exam-ple, whole genome sequencing of the avirulent chemical mutant TIGB03 revealed a large 75.5 kb tandem duplication flanked by transposable elements, while the genome of a virulent Clone01 (vir-[wbtK+]TIGB03-C1) lost one copy of the 75.5 kb tandem duplicated region but gained a tandem duplication of another large 80kb region that contains a virulence associated transcription factor SspA. RNAseq data showed that the dosage effect of this extra region in Clone1 suppresses expression of MglA regulated genes. Since MglA regulates genes that are known to be crucial for virulence, including the well-studied Francisella Pathogenicity Island (FPI), these results suggest that gene dosage effects arising from large duplications can trigger unknown virulence mechanisms in F. tularensis subsp. tularensis. These results are important especially when designing live vaccine strains that have repeated insertion elements in their genomes. / Ph. D.
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The influence of formulation and medicine delivery system on medication administration errors in care homes for older peopleAlldred, David P., Standage, C., Fletcher, O., Savage, I., Carpenter, J., Barber, N.D., Raynor, D.K. January 2011 (has links)
No / Introduction Older people in care homes are at increased risk of medication errors and adverse drug events. The effect of formulation on administration errors is not known, that is whether the medicine is a tablet or capsule, liquid or device such as an inhaler. Also, the impact on administration errors of monitored dosage systems (MDS), commonly used in UK care homes to dispense tablets and capsules, is not known. This study investigated the influence of formulation and MDS on administration errors.
Methods Administration errors were identified by pharmacists (using validated definitions) observing two drug rounds of residents randomly selected from a purposive sample of UK nursing and residential homes. Errors were classified and analysed by formulation and medicine delivery system.
Results The odds of administration errors by formulation, when compared with tablets and capsules in MDS, were: liquids 4.31 (95% CI 2.02 to 9.21; p=0.0002); topicals/transdermals/injections 19.61 (95% CI 6.90 to 55.73; p<0.0001); inhalers 33.58 (95% CI 12.51 to 90.19; p<0.0001). The odds of administration errors for tablets and capsules not in MDS were double those that were dispensed in MDS (adjusted OR 2.14, 95% CI 1.02 to 4.51; p=0.04).
Conclusions Inhalers and liquid medicines were associated with significantly increased odds of administration errors. Training of staff in safe administration of these formulations needs implementing. Although there was some evidence that MDS reduced the odds of an administration error, the use of MDS impacts on other aspects of medicines management. Because of this, and as the primary topic of our study was not MDS, a prospective trial specifically designed to evaluate the overall impact of MDS on medicine management in care homes is needed.
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Modelling the mechanical behaviour of a pharmaceutical tablet using PDEsAhmat, Norhayati, Ugail, Hassan, Gonzalez Castro, Gabriela 01 1900 (has links)
Yes / Detailed design of pharmaceutical tablets is essential nowadays in order to produce robust tablets with tailor-made properties. Compressibility and compactibility are the main compaction properties involved in the design and development of solid dosage forms. The data obtained from measured forces and displacements of the punch are normally analysed using the Heckel model to assess the mechanical behaviour of pharmaceutical powders. In this paper, we present a technique for shape modelling of pharmaceutical tablets based on the PDE method. We extended the formulation of the PDE method to a higher dimensional space in order to generate a solid tablet and a cuboid mesh is created to represent the tablet’s components. We also modelled the displacement components of a compressed PDE-based representation of a tablet by utilising the solution of the axisymmetric boundary value problem for a finite cylinder subject to a uniform axial load. The experimental data and the results obtained from the developed model are shown in Heckel plots and a good agreement is found between both. / Available in full text since 5th Feb 2013 following the publisher's embargo period.
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The role of inflammation in delayed muscle soreness (DMS) and the effects of indomethacin on DMS and perceived exertionSmith, Lucille Lakier January 1986 (has links)
PART I: MARKERS OF INFLAMMATION IN DELAYED MUSCLE SORENESS
Fifty-five untrained males were assigned to an experimental (E) or a control group (C), to re-examine the concept that DMS represents an acute inflammatory response. Subjects were assigned to receive either Indocin (Id; 100 mg per day) for 2 days prior to the treatment and a placebo (P) for 2 days after (Id-P); or the reverse combination (P-Id); or Id for- 4 days (Id-Id); or placebo (P-P). On the treatment day, to induce DMS, E subjects performed 30 min of bench-stepping with one leg leading throughout; C subjects rested for 30 min. Immediately before and after stepping/resting, all subjects used their right and left leg to perform 19 maximal and 15 submaximal repetitions on the Cybex II. Blood samples were collected -5 min before, immediately after bench stepping (0 h), 2 h after and 24, 48 and 72 h, to evaluate WBC. DMS was also monitored 0, 24, 48 and 72 h. All E subjects experienced a significant amount of DMS (p<.01) which peaked at 48 h after exercise (E=7.58 ± .79 vs 0 for C, X±SEM); however, no significant differences in soreness perception were observed between drug and placebo groups. Total WBC count ( cells/mm³ ) was significantly greater at 0 h (8,340±380) than at -5 min (6,699±365) for both E and C; this increase was most likely a response to Cybex exercise. At 2 h there was a significant increase in total WBC count for E ( 9,603±389) and no change for C ( 8,336±273}. Neutrophils increased significantly at 2 h for E only (6,428±375 vs 4,988±261 for C}. Bench-stepping leads to increases in DMS and increases in WBC count, particularly in neutrophils, 2 h after stepping; this data suggests that inflammation is involved in DMS.
PART II: EFFECT OF AN ASPIRIN-LIKE DRUG ON PERCEIVED EXERTION DURING BENCH STEPPING
The object of this study was to determine whether perceived exertion (RPE) for the limb performing predominantly positive work was significantly greater than for the limb performing predominantly negative work, during 30 min of bench stepping. A second objective was to determine the effects of indomethacin (Id) on RPE. Thirty-nine males were randomly assigned to a drug (Id) or placebo (P) group and administered 150 mg indomechacin or placebo, beginning 36 h prior to stepping. Results indicated no significant differences between RPE for "concentric" and "eccentric" limbs of the P group inspite of the fact that the metabolic demand of the "concentric" limb was much greater. Indomethacin did not significantly alter RPE during stepping however, when RPE scores were totaled over the entire bench stepping period, the Id condition was associated with a greater (p < .01) psychological cost for the "concentric" leg effort as compared to P; this indicated that indomethacin might alter effort sense related to concentric contractions. / Ph. D.
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