Co-crystals are multi-component, single phase materials in which the co-crystal formers exist in an uncharged state. This interaction between components occurs without affecting the intra-molecular covalent bonding of the involved components or altering their chemical integrity. This class of materials has recently gained the interest in the pharmaceutical industry for modifying the physico-chemical properties of some active pharmaceutical ingredients (APIs) such as solubility, hygroscopicity, and mechanical properties. However like all multi-component systems, there are some analytical challenges associated with using traditional quality control (QC) tools that involve sample preparation steps prior to the analysis. This can sometimes have an impact on the physical state of such systems and therefore affect the outcomes of analysis correlated with the actual materials. Flurbiprofen (FBP) and nicotinamide (NCT) in this work were selected to form a model co-crystal system. FBP falls in the carboxylated group of non steroidal anti-inflammatory drugs (NSAIDs), used herein as an API. It belongs to class II of the Biopharmaceutics Classification System (BCS), therefore its low aqueous solubility and dissolution rate affect its bioavailability. NCT is a vitamin B3 derivative and generally regarded as safe (GRAS) substance. It is used as co-crystallising agent due to its solubility enhancing property. FBP-NCT co-crystal system was previously studied by Berry et al., where a FBP-NCT co-crystal was prepared using Kofler method and screened by means of the hot-stage microscopy (HSM). FBP-NCT co-crystal was recently prepared via rapid evaporation from ethanol solution, and screened for its physicochemical and mechanical properties by Shing et al. who found an improvement in such properties compared to the pure API (FBP). There is a wide range of methods for preparing co-crystals, of which methodologies with minimal environment impact were mainly adopted in this work i.e., Ko er fusion and co-grinding methods. Within the Kofler fusion method, it was feasible to identify and screen simultaneously parent components as well as the emerging material at room temperature (RT) by means of confocal Raman microscopy. Detailed information from Raman mapping on the investigated phases were achieved using statistical analysis. The analysis resulted in a refinement regarding the traditional assumption about the binary phase diagram. It also revealed the presence of two forms of FBP-NCT co-crystals which were consequently explored by coupling thermal analysis with Raman spectroscopy and X-ray diffraction. Using co-grinding preparation, FBP-NCT co-crystals were prepared on a large scale; enough for solid dosage formulation. Subsequent crystallisation of the resulting compound using a solution method generated single crystals suitable for x-ray crystal structure determination. Moreover in this work, a solid-state dosage form of FBP-NCT co-crystal was prepared for the first time, then investigated using transmission Raman spectroscopy. The investigation included the presence of drug and excipient, and their composition in tablets. This procedure can be considered as a platform for studying the QC of drug preparation, using a reliable, non-destructive, non-invasive, and very rapid analytical tool. Such type of study complied well with the food and drug administrative (FDA) outlines on employing process analytical technology (PAT) protocol for analysing and controlling pharmaceutical manufacturing processes.

The bactericidal mechanism of hydrogen peroxide is poorly understood, with most evidence being obtained from studies involving greatly reduced concentrations aimed at investigating the effects of stress. Current theory suggests that this mechanism is based on the oxidation of protein, DNA and lipids within the cell by the production of free hydroxyl radicals through the interaction of hydrogen peroxide and intracellular iron. The mechanism of vapour phase hydrogen peroxide treatment remains unstudied, despite evidence that it may be different to the liquid phase. This study aimed to investigate the effects of bactericidal treatments of liquid and vapour phase hydrogen peroxide on the macromolecular components of a model organism, Escherichia coli strain K12. A set of treatment conditions producing a range of reductions in colony forming units was identified, and the effects of these conditions on the protein, DNA and lipid constituents of the cells assayed. No effect on the lipid contents and membrane integrity of treated cells was found. Liquid hydrogen peroxide was found to reduce the thiol content of cytoplasmic protein, but this was not found to be a major mechanism of bactericidal action. Extensive fragmentation of DNA was found to result by treatment with both phases, the degree of which was correlated with a reduction in colony forming unit counts. No effect on bactericidal action was found on addition of a hydroxyl radical scavenger or an inhibitor of protein synthesis, showing that DNA damage was due to the primary action of hydrogen peroxide, and that this damage was not caused by the production of free radicals within the cell. A modifed mechanism of hydrogen peroxide bactericidal action is proposed, whereby lethality is due solely to DNA damage caused by the production of ferryl radicals by the interaction of hydrogen peroxide and iron associated with the DNA backbone.

One third of the world’s population is estimated to be infected with M. tuberculosis, a pathogen which causes more human death and misery than any other bacterial disease. Whilst treatment is available, resistance to commonly used antimicrobials is a growing problem. Thus there is an urgent need to identify new compounds that can kill drug resistant isolates and are able to potentiate the activity of currently available antibiotics. The plant kingdom is a rich source of antibacterial compounds and a plant which has attracted particular interest is Humulus lupulus, more commonly known as the hop, which has been used as an antibacterial in beer for hundreds of years. Its antibacterial properties are thought to be due to the combined action of alpha and beta acids and polyphenols such as xanthohumol although the precise nature of their interactions and relative importance has yet to be determined. An optimised agar antimicrobial assay was developed and employed based on Mycobacterium smegmatis, to characterize the antibacterial activity of fifty commercially available hop varieties with a view to identifying novel antibacterial compounds. Surprisingly, no correlation was found between alpha and beta acid content and antibacterial activity. Chemical analysis of the most (Citra) and least (Galena) active hop variants using a combination of bioactivity based thin layer chromatography, mass spectrometry and HPLC revealed differences in the relative amounts of antimicrobial compounds such as humulone (alpha acid), lupulone (beta acid) and xanthohumol but failed to identify the presence of novel antibacterial compounds. Whilst no new antimicrobial compounds were identified, the Citra hop extract was able to potentiate the activity of the antibiotics imipenem and ciprofloxacin against clinical isolates of M. abscessus, a fast growing member of the mycobacterium family which infects individuals suffering from cystic fibrosis. The Citra hop extract also inhibited the growth drug resistant isolates of M. abscessus suggesting that it may have activity against other antibiotic resistant mycobacteria such as M. tuberculosis With regards to the mode of action, scanning electron microscopy revealed distinct changes to the outer cell structure of the bacteria, suggesting that hops contain compounds that interact with the bacterial cell membrane and/or cell wall. These changes were more profound in the presence of sub-inhibitory concentrations of imipenem, a compound which also targets the cell wall. Overall hops were shown to contain compounds which inhibited the growth of mycobacterium and were able to potentate the activity of antibiotics currently used to treat these pathogens. These findings suggest hops may be a fruitful source from which to isolate next generation compounds with which to treat increasingly drug resistant strains of mycobacteria.

A series of microgels have been prepared by a surfactant free emulsion polymerisation based on an N-isopropylacrylamide (NIPAM) monomer. Poly(NIPAM) is a thermo sensitive polymer which undergoes a conformational transition close to the human skin temperature. Poly(NIPAM) was co-polymerized with hydrophobic butyl acrylate (BA) to provide a more favourable environment for drug molecules to partition into within the particle. A second co-monomer, acrylic acid (AA) was used to prepare pH/temperature sensitive microgels. The coupling reactions between microgels and cotton cellulose are only feasible if they both have appropriate functionalities. For microgels, this was achieved by using different initiators which introduce different functional groups on the particle surfaces and different surface changes. Cotton samples were successfully modified by carboxymethylation, periodate oxidation, grafting of 1,2,3,4-butanetetracarboxylic acid, and chloroacetylation in order to target possible reactions with the terminal functional groups of the microgel particles. Microgels were attached to the cotton fabrics using different methods. The maximum weight increase of cotton samples due to the attached microgels was 23.51 ± 0.29% (w/w). Drug loading and drug release were studied for free (unattached) microgels and novel wound dressings. Methyl paraben (MP) was used as a model drug compound. The results of MP release from free microgels show no significant influence of surface charge on MP release. However, BA-containing microgel particles release less MP than 100% poly(NIPAM) microgels due to hydrophobic interactions between the MP and the BA. Temperature-sensitive dressings release up to 45% more MP at 40°C than at 30°C. The drug release for pH-sensitive dressings was up to 24% higher at pH 5 than at pH 8. This demonstrates that the novel dressings can be classed as “smart” materials as they can respond to subtle changes in simulated wound fluid temperature and pH.

Intravenous lipid emulsions are used ubiquitously through the medical field as a source of parenteral nutrition. Development of new formulations requires an understanding of the metabolism of the product. Current methods of rate determination and of metabolism analysis have several drawbacks. Radioactive labelled assays have lower biological relevance, are time consuming due to separation steps and require long substrate preparation. Existing fluorescence assays based around triglyceride hydrolysis are impractical in emulsion systems due to high signal-noise ratio as well as the use of non-specific fluorescent dyes. Colorimetric methods such as the non-esterified fatty acids (NEFA) assay is expensive, requires multiple steps and specialised machinery. Due to the limitations of these techniques we developed a novel fluorescent assay using a lipoprotein lipase specific substrate incorporated into lipid emulsions. The lipoprotein lipase substrate, EnzChek® Lipase Substrate, green fluorescent, 505/515, is based on a triglyceride structure with a fluorescent dye at the Sn1 position and a dark quencher at the Sn2 position. LPL cleaves preferentially at the Sn1 position of triglycerides, which separates the dye from the quencher creating a fluorescent signal. The signal can then be detected using a fluorescent plate reader. Both lipid emulsion particles and EnzChek are substrates for LPL, so the hydrolysis of EnzChek is analogous for native emulsions particles. Over time, in the presence of LPL, fluorescent signal increases as more EnzChek is hydrolysed in tandem with emulsion particles. We have designed a range of emulsions with varied oil and surfactant composition. Using the EnzChek emulsion assay detailed above we are able to follow the rate of metabolism in real-time. This assay has been tested and found to be robust and reproducible. It is able to investigate differences in metabolism between Soybean oil, medium-chain triglyceride and fish oil emulsions. As well as changes in surfactant type and concentration.

The modular polyketide synthase responsible for biosynthesis of the antibiotic mupirocin occupies 75 kb of Pseudomonas fluorescens NCIMB 10586, while a hybrid of PKS/NRPS is responsible for biosynthesis of the antibiotic thiomarinol located on a 97 kb plasmid pTML1 in Pseudoalteromonas spp SANK 73390. Biosynthesis of the acyl side chains in mupirocin and thiomarinol are thought to be either through esterification of the fully synthesised fatty acid (C\(_9\) or C\(_8\)) or through extension of the PK derived ester starter unit which is predicted to be carried out on MmpB and TmpB. mupU/O/V/C/F and macpE are proposed to be sufficient for the conversion of pseudomonic acid B to pseudomonic acid A. Mupirocin is regulated via quorum sensing, while regulation of thiomarinol was not identified. Production of thiomarinol was determined to occur after 8 hours of growth, while acidic conditions and use of acetone with ethyl acetate improved the extraction. TmlU, the thiomarinol amide ligase, did not complement a mupU mutant in mupirocin, and was found to block the biosynthesis of 9-hydroxynonanoic acid, causing truncation of 9-HN. This suggests that MupU, prevents MmpB from being an iterative PKS. KS-B2/ACP-B2 was shown to be involved in the removal of C8-OH from thiomarinol. Genetically manipulated mupU increased the production of mupirocin to 3 to 4 fold without abolishing PA-B production. Fused mupU-macpE complemented the NCIMB10586ΔmupUΔmacpE double mutant. However, insertion of this fusion into MmpB blocked the biosynthesis of mupirocin, while insertion after MmpA did not changed the pathway. Attempts to mobilise pTML1 revealed that a hybrid plasmid of RK2-R6K γ-ori was integrated into pTML1 but recovery of this cointegrate has not yet been recovered in E. coli.

Haemorrhage remains a leading cause of death in civilian and military environments. Recent research into emergency treatments for severe haemorrhaging injuries has resulted in production of a number of advanced haemostatic products. In certain scenarios, concomitant release of toxic materials may exacerbate trauma and ultimately reduce survival from such injuries. In particular, systemic absorption of the nerve agent VX (S-[2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate) via wounds may rapidly cause muscle paralysis and death. This research explored the hypothesis that a haemostatic product could perform an additional function as a wound decontaminant. […] In summary, this project has successfully demonstrated that haemostatic products, based on an adsorptive mechanism of action, offer a highly effective means of countering the rapidly fatal effects of the chemical warfare agent VX present in wounded skin tissue. Further development of the concept of a haemostatic decontaminant has life-saving implications.

An analysis of over 34,000 free-text messages assigned by pharmacists to prescription orders over a 12-month period showed a sub-optimal exchange of information with the physician. Focus groups and observational research were conducted to provide a more in-depth understanding of the factors involved. The use of CPOE did not reduce opportunities for personal interaction. The capability to communicate electronically facilitated a non-interruptive workflow, beneficial for staff time and for limiting distractions. It also improved clinical documentation, which helped coordinate care of patients between members of the pharmacy team. However, the research identified several barriers to the effectiveness of communication via the CPOE system, including: the increased frequency of messages sent; poor display characteristics of the message; poor access to information to inform decision-making; one-way communication; and no assigned responsibility to respond. These factors need to be considered in the design of systems and supported by interprofessional training to optimise communication between the professionals.

There is a clear and well-established need for new antibiotics. The biosynthesis of the antibiotic mupirocin is an important model trans-AT polyketide synthase pathway. A key tailoring step is the removal of a hydroxyl from the intermediate pseudomonic acid B (PA-B), which generates active pseudomonic acid A (PA-A). This is proposed to occur on discrete proteins after release from enzyme MmpB. In this work, a systematic screen for genes required for this key step was developed, which implicated ten genes. On a multi-gene expression plasmid, these ten genes encoded all functions necessary for conversion. This re-identified seven genes from the existing proposed model. A novel requirement for MupM, MupN, and the DNA sequence but not protein function ofMupL was uncovered. This represents the first identification of all genes required for this surprisingly convoluted pathway. With the aim of re-engineering the location of these tailoring steps, domains from thiomarinol enzyme TmpB were inserted into MmpB. Low-level conversion to PA-A was achieved using thiomarinol tailoring enzymes. The TmpB KS0 domain was used to load the normally free-standing MacpE, and high-level conversion was achieved on the hybrid enzyme. This success opens the future path to further MmpB modifications to generate mupirocin derivatives.

Polyketide synthases (PKS) are enzyme complexes that synthesise many natural products of medicinal interest, notably a large number of antibiotics. The present work investigated the mupirocin biosynthesis system, comparing it with similar pathways such as thiomarinol and kalimantacin. The focus was on the structural modelling of the protein complexes involved in antibiotic synthesis, via molecular simulation and the analysis of structural and sequence data. Structural docking of acyl carrier proteins (ACP) cognate for an HMG-CoA synthase orthologue responsible for β-methylation (MupH) identified key residues involved in the recognitions specificity of the interacting partners, further supported by mutagenesis experiments, which thus allows prediction of β-methylation sites in PKS. Moreover, complementation and mutagenesis experiments performed on MupH homologs from kalimantacin and thiomarinol systems suggests specificity between the ACP:HCS proteins in the β-branching suggesting the possibility of engineering multiple specific β-branching modifications into the same pathway. Molecular dynamics simulations of ACPs from the mupirocin cluster revealed that the PKS ACPs form a cavity upon the attachment of the phosphopantetheine and acyl chains similar to what is seen in the fatty acid synthase ACPs and provide a better understanding of the structure function relationship in these small proteins. Molecular docking of the putative cognate substrate with the ketosynthase (KS) homo dimer of module 5 of the MmpA in the mupirocin pathway revealed a loop that may control specificity for the α-hydroxylated substrate and mutagenesis experiments support this proposition.