Polymer drug dispersions: understanding structure and dynamics

Poor physical stability is a limiting factor in the pharmaceutical development of APIs. Amorphous drugs are attractive due to increased dissolution; however can unpredictably revert to the thermodynamically stable crystalline form. Accurate prediction of molecular level physical stability would be advantageous. Research surrounding stability prediction is evolving; but challenging, including thermodynamic, molecular and kinetic factors. This study focussed on gaining a molecular level understanding of the structure and dynamics of amorphous dispersions using three model drugs. We aimed to develop solid-state NMR methods to provide invaluable information on molecular mobility; to ultimately use NMR for the prediction of crystallisation outcomes from stability studies, leading to quicker prediction of potential storage issues, since mobility is a key factor a�ecting stability in the amorphous state. VT solid-state NMR was used to probe di�erences in local mobility between drug and polymer; and to monitor polymorphic transitions/crystallisation in high loaded dispersions. Methodologies were veri�ed using additional physicochemical approaches. We demonstrated: • Di�erences in local mobility of drug/polymer dependent on model system and drug loading. • Miscibility detection down to 2 nm, including important temperature dependent observations. VT relaxation curves could become important visual tools for quanti�cation of drug loading and prediction of miscibility during initial development. • VT NMR was a useful tool for quick and accurate prediction of high temperature stability study outcomes • Insight into crystallisation of pharmaceuticals in formulation, demonstrating mapping complex phase transitions in high loaded dispersions • Detection of di�erent dynamic features of tolbutamide, including the identi�cation of motional processes responsible for the detection of its structural transitions VT solid-state NMR has provided a signi�cant quantity of data surrounding the mobility and stability of our systems of study. These methods provide us with a valuable characterisation `toolkit' for probing molecular mobility in solid dispersions, therefore aiding the prediction of potential long term stability issues

Enhanced star formation: The importance of bars in spiral galaxies

It was found that among an IR luminous subset of nearby spiral galaxies, nearly all of the systems with IRAS colors and luminosities indicative of enhanced star formation are barred. Radio continuum and IR spectroscopic results support the hypothesis that this emission originates within the central 2 kpc; possibly in a circumnuclear ring. It was also found that outer rings are over represented among these barred systems and suggest possible reasons for this phenomena

Seeing statistics at the upgraded 3.8m UK infrared telescope (UKIRT)

From 1991 until 1997, the 3.8m UK Infrared Telescope (UKIRT) underwent a programme of upgrades aimed at improving its intrinsic optical performance. This resulted in images with a FWHM of 0."17 at 2.2 um in September 1998. To understand and maintain the improvements to the delivered image quality since the completion of the upgrades programme, we have regularly monitored the overall atmospheric seeing, as measured by radial displacements of subaperture images (i.e. seeing-generated focus fluctuations), and the delivered image diameters. The latter have been measured and recorded automatically since the beginning of 2001 whenever the facility imager UFTI (UKIRT Fast Track Imager) has been in use. In this paper we report the results of these measurements. We investigate the relation between the delivered image diameter and the RMS atmospheric seeing (as measured by focus fluctuations, mentioned above). We find that the best seeing occurs in the second half of the night, generally after 2am HST and that the best seeing occurs in the summer between the months of July and September. We also find that the relationship between Zrms and delivered image diameter is uncertain. As a result Zrms frequently predicts a larger FWHM than that measured in the images. Finally, we show that there is no correlation between near-infrared seeing measured at UKIRT and sub-mm seeing measured at the Caltech Submillimetre Observatory (CSO).Comment: 10 pages to appear in the SPIE proceeding vol. 4484 on Observatory Operations to Maximize Scientific Retur

Does formal workplace based assessment add value to informal feedback?

Feedback is a key component of learning but effective feedback is a complex process with many aspects. One aspect may be a written summary which is passed to the learner but this may not be valued by learners. We examined the role of written feedback in the feedback process to determine whether it does more than provide a simple summary of the interaction. We conducted a secondary analysis of data gathered for a study of formative workplace based assessment. Interview data from 24 interviews with students and written summaries of workplace based assessments for 23 of them were reanalysed by two researchers who were already immersed in the data and examined all references to verbal, informal feedback and written, formal feedback or the assessment tool used. We found that students valued the verbal feedback discussion highly and that they often considered the written summaries superfluous. We also found that the act of preparing written feedback augmented the feedback discussion and tutors had adopted the language of the formal instrument in the verbal feedback and free text written feedback. What this study adds to existing research is evidence that there may be a secondary faculty development effect of requiring the preparation of written feedback which has served to enhance the educational content of feedback. Although this is not proof of causality (the requirement to provide written feedback alone producing the positive effects), we consider that the likelihood is sufficiently strong to continue the practice

The response of SME manufacturers to the HIV/AIDs crisis

The social, demographic and economic consequences of the HIV/AIDS pandemic are disturbing for South Africa, and the implications for business are great. The objective of this research was to establish the impact of HIV/AIDS on small and medium-sized enterprises in the manufacturing industry as the majority of employees within this industry are semi- and unskilled and it is this level of employee who has been most severely affected by the epidemic. In addition, the research attempts to analyse how companies have responded to the epidemic and lastly, to determine what has facilitated and hindered their response.The research was conducted using structured, face to face interviews with twenty small to medium organisations in central Gauteng employing from 20 to 300 people. The questionnaire addressed the impact of HIV/AIDS on the organisation and the subsequent response to the epidemic.The findings reveal that SME manufacturing organisations are experiencing the impact of HIV/AIDS, yet there is a disconnect between impact and response. The majority of companies are not proactively taking action to manage the consequences of the epidemic. Factors contributing towards the limited response are: negative implications of stigma, lack of information, perceived cost of response, time required to respond and uncertainty about the role of government. It appears that the long-term economic consequences of the epidemic have not been considered by companies when determining the nature and extent of their response.Dissertation (MBA)--University of Pretoria, 2010.Gordon Institute of Business Science (GIBS)unrestricte

Nanocrystallization of Rare Tolbutamide Form V in Mesoporous MCM-41 Silica

Encapsulation of pharmaceuticals inside nanoporous materials is of increasing interest due to their possible applications as new generation therapeutics, theranostic platforms, or smart devices. Mesoporous silicas are leading materials to be used as nanohosts for pharmaceuticals. Further development of new generation of nanoscale therapeutics requires complete understanding of the complex host−guest interactions of organic molecules confined in nanosized chambers at different length scales. In this context, we present results showing control over formation and phase transition of nanosize crystals of model flexible pharmaceutical molecule tolbutamide confined inside 3.2 nm pores of the MCM-41 host. Using low loading levels (up to 30 wt %), we were able to stabilize the drug in highly dynamic amorphous/disordered state or direct the crystallization of the drug into highly metastable nanocrystalline form V of tolbutamide (at loading levels of 40 and 50 wt %), providing first experimental evidence for crystallization of pharmaceuticals inside the pores as narrow as 3.2 nm

Love books : sustained success amidst uncertainties

SUBJECT AREA : The sub field of academia that the case is designed to teach is small business development, entrepreneurship or women in business. STUDY LEVEL/APPLICABILITY : This case is appropriate for graduate and post-graduate, MBA and executive education students focusing on entrepreneurship, small business development or women in business. CASE OVERVIEW : This real-life case is based on interviews that took place with Kate Rogan, the co-founder of Love Books, and other stakeholders associated with the small bookselling business that is based in the suburb of Melville in Johannesburg. It describes how Rogan’s past influenced how she saw and was open to the opportunity; and how, through passion, commitment, dedication and stakeholder management, she created a business that brought meaning to her and others’ lives. Rogan’s vast experience in editing, publishing and radio influenced how she evaluated the bookstore opportunity. For the past 11 years, she focused on building a loyal customer base through knowing her customers, staying on top of current industry and market trends and constantly thinking about how she could add value through minimal financial outlay. COVID-19 further complicated her thinking about how to traditionally market and sell books to her client base. As the case concludes, Rogan wonders how to build upon the foundations of her successful bookshop and grow profitability while remaining true to her and the business’s values. EXPECTED LEARNING OUTCOMES : The case allows students to consider the key enablers for assessing entrepreneurial opportunities and drivers of small business growth. Following discussion and analysis of the case, students should be able to: explore how cognitive dynamics affect an entrepreneur’s evaluation of opportunities; analyze the case against the 4Cs (continuity, community, connection and command) of competitive business advantage; evaluate building blocks for sustainable business profitability; and assess and recommend different learnings for entrepreneurs and small business owners.https://www.emerald.com/insight/browse/case-studies?collections=EEMCShj2022Gordon Institute of Business Science (GIBS

Old southern open clusters

The six chapters of this thesis contain the results of four years spent in the investigation of old open clusters at the SAAO. Each chapter is a preprint of a paper which has been submitted or accepted for publication and is therefore an independent entity with its own list of acknowledgements and references. Since each chapter is intelligible without continual reference to its fellow chapters, considerable overlap has sometimes occurred. As a thesis, the end product is of necessity a little disjointed. This approach has been adopted because 'the publication of the results has higher priority than the presentation of a thesis. The style is as compact as seems consistent with reasonable clarity and I hope that reading it will not present too great a problem of digestion to those interested in the evolution of solar-type stars