The prediction of percutaneous absorption is of enormous importance for the effective design, development and quality assessment of topical and transdermal formulations. In vitro diffusion experiments are widely carried out for such predictions and are of substantial interest across the pharmaceutical and cosmetic industries. Human or animal skin, usually excised, are often used in in vitro drug diffusion studies. However, difficulties in obtaining the mammalian skin and variation in their permeability directed researchers towards using synthetic membranes as skin mimics in preformulation screening experiments, where a large number of experiments are required. Polydimethylsiloxane (PDMS) membranes have been accepted as the most commonly used in vitro skin mimic because of their homogeneity, uniformity and skin-analogous rate-limiting permeation properties. This thesis investigates the effects of ionisation and surfactants on the permeation of pharmaceutical compounds of varied physicochemical properties through PDMS membranes using a flow-through diffusion cell system. Data suggests that drug permeation had a dependency on the extent of its ionisation, with the permeation being more favourable for the more unionised form of a drug. All of the surfactants studied were found to reduce the permeation of the drugs, with an inverse relationship being observed between the surfactant concentration and the amount of drug permeated. DSC (differential scanning calorimetry), SEM (scanning electron microscopy), FTIR (Fourier transform infrared) and NMR (nuclear magnetic resonance) spectroscopy were employed to study the interactions between the membrane and the surfactants. Results indicated that the permeation effects of the surfactants are a consequence of the interactions between the drugs and surfactant micelles, and/or the membrane and the surfactants. Air plasma treatment was used to modify the PDMS surfaces to become hydrophilic, which was confirmed by water contact angle (WCA) and SEM-EDX analysis. The permeation data for the modified membranes revealed that the plasma-induced hydrophilicity significantly reduced the fluxes of the hydrophobic compounds, while not affecting that of the hydrophilic drug. Aging studies of the plasma-treated membranes showed that the hydrophilic surfaces were maintained even after 8 weeks under airtight storage conditions. In summary, ionisation and surfactant effects on drug permeation across PDMS were thoroughly investigated, and plasma treatment was found to be a stable, economic and convenient method of modifying PDMS to offer skin-like slower drug permeation i.e. to produce a potential in vitro skin mimic.

An investigation into the aspects of innovation within the downstream domain of the pharmaceutical supply chain This research evaluates the implementation of innovative programmes within the downstream domain of the Pharmaceutical Supply Chain (PSC). Pharmacies are considered as key links between healthcare services and patients because they are responsible for dispensing and managing pharmaceuticals in order to prolong life. Considering the healthcare organisations‘ crucial role and that they face the challenge of minimising the cost of healthcare services while enhancing service quality, healthcare organisations tend to try improvement approaches and innovative interventions to enhance their efficiency and effectiveness. Specifically, they tend to focus on improving their Supply Chain Management (SCM) in order to reduce waste, in particular with regards to their medicine expenditure, and to provide improved services. However, implementing innovation within the Pharmaceutical Supply Chain (PSC) is not yet adequate; at present there appears to be a lack of experience and knowledge of how such initiatives should be undertaken. Research that examines potential innovative contributions might therefore make a defined contribution to the sector. This research, therefore, aims to assess the current medicine delivery process and identify the issues responsible for weak process performances and the factors that influence pharmacies‘ innovativeness within two diverse European contexts, the UK and Greece. An exploratory research design, embracing a mixed-methods approach, was used to analyse the issues associated with PSC inefficiency and assess to what extent innovation could be adopted by hospital and community pharmacies to improve the delivery process of pharmaceutical products. The qualitative data was gathered through 30 interviews with key professionals working within the downstream domain of the PSC in the two selected geographical areas. A total of 21 in-depth interviews in the UK and 9 in Greece were conducted to examine the elements preventing the effective and efficient delivery of medicines. Simultaneously, an online survey was developed to collect the quantitative data. The final sample (N=130) consisted of specialists working within the down stream domain of the PSC in Greece and the UK. The quantitative data analysis aimed to identify the factors that support or prevent innovation within this specific and complex environment. The analysis and combination of these two sets of data enabled the researcher to gain a comprehensive understanding and recommend innovative solutions that are suitable to the system under investigation, leading to continuous improvement. This research contriputes to academic literature as it adds more theoritical insights to innovative delively processes, especially those that have been characterised as highly complex. The results led to the generation of the Innovative Pharmaceutical Supply Chain Framework (IPSCF) that provides guidelines to healthcare organisations about how the identified problems can be overcome by implementing suitable innovative techniques. The implementation of Lean and Reverse Logistics practices, which are supported by integrated Information Technology (IT) systems, are suggested as a means for healthcare organisations to enhance their delivery system in terms of quality (products and service quality), visibility (knowledge and information sharing), speed (respond to customers and suppliers needs) and cost (minimisation of cost and waste) and therefore generate a competitive edge. The study‘s recommendations have important implications for pharmacies, as they provide guidance regards suitable innovative programmes that can be adopted. The outputs of this research are specifically relevant to the pharmacy sectors of the UK and Greece, but may have also relevance for European healthcare organisations.

Chemical risk assessment for human health effects is performed in order to establish safe exposure levels of chemicals to which individuals are exposed. The process of risk assessment traditionally involves the generation of toxicological studies from which health based guidance values are derived for a specific chemical. For low level exposures to chemicals, where there are no or limited chemical specific toxicity data, the application of the Threshold of Toxicological Concern (TTC) approach may estimate whether the exposure levels can be considered safe. The TTC approach has recently gained increasing interest as new requirements, under different regulatory frameworks, emerge for the safety assessment of chemicals and to assess chemicals for which testing is not routinely required. The application of TTC relies heavily on computational (in silico) methods. In silico tools are computer implemented models that, based on commonalities in the toxicity of “similar” chemical structures, may predict hazard. In silico methods are rapidly evolving and gaining importance within the context of Integrated Approaches to Testing and Assessment (IATA) and their acceptance for regulatory purposes is expanding. The work presented in this thesis has focused on the use and applicability of a wide range of computational approaches to assist in the application of the TTC concept. In the TTC approach, the identification of genotoxic chemicals is a primary requirement. In silico approaches apply expert knowledge and/or statistical methods to either predict genotoxicity or to identify structural alerts associated with it. This thesis focused, in part, on a group of important environmental pollutants, nitrobenzenes, to assess the applicability of in silico tools to predict genotoxicity. For this purpose a dataset containing 252 nitrobenzenes including Ames test results was compiled. Based on these test results a case study for sodium nitro-guaiacolate, a pesticide active substance, was developed. The case study demonstrated that (Q)SAR and a category approach incorporating read-across, are applicable for the prediction of genotoxicity and supports their use within a weight of evidence approach. Another aspect of the TTC approach is the evaluation of repeat dose, non-cancer endpoints. For that purpose chemicals are separated into groups related to three levels of concern based on the Cramer classification. For each level, namely the Cramer Classes (I, II and III), a safe exposure level has been established. Therefore, as interest to apply TTC expands to new groups of chemicals, the reliability and conservativeness of the established thresholds relative to Cramer Classes for the new chemistries must be established. In this thesis the TTC approach was evaluated for 385 cosmetic ingredients, 77 biocides and 102 compounds classified as reproductive and developmental toxicants. To support the evaluation at different levels, chemical datasets containing toxicological data were utilised and computational tools were applied to compare datasets. The results indicated, that the historical “Munro” dataset is broadly representative for cosmetics and biocides. In addition, that the threshold levels for Cramer Class III are within the range of Munro’s threshold further supports the validity of the TTC approach and its conservativeness for the groups of chemicals analysed. Cramer Class I thresholds were found to be valid only for classified developmental and reproductive toxicants. The results also supported the validity of the classification of chemicals into Cramer class III. It is foreseen that the TTC approach will gain increasing acceptance in the risk assessment of different groups of chemicals. Therefore it is emphasised that the future work should focus on the identification of the limitations of the application of TTC, including the identification of groups of chemicals to which TTC cannot be applied, the expansion of the underlying toxicological datasets, and the development of tools to support the application of TTC so that is transparent and acceptable for regulatory purposes.

Clays and clay minerals (phyllosilicates) have been used for millennia to treat a range of human maladies, such as infected wounds and diseases of the skin. The unique chemistry of phyllosilicates allows them to support the wound environment and encourage healing. Their physicochemical properties can also be utilised to develop modified drug-release formulations and also enables their incorporation into polymer matrices for the development of advanced wound care materials. By developing novel antibacterial phyllosilicate-polymer composite materials it should be possible to support wound healing, whilst simultaneously treating infections locally to avoid systemic adverse effects and prevent the development of antimicrobial resistance. In this research project the clay minerals kaolin (KN), refined montmorillonite (rMMT), montmorilonite K10 (MMTK10), Laponite® RD (LRD), and Laponite® XL21 (LXL21) were investigated for their differing structure and physicochemical properties. Their ability to adsorb and desorb the antibacterial agents tetracycline (TC), doxycycline (DC) and ciprofloxacin (CIP) was determined through a series of adsorption kinetics and isotherm studies. LRD and LXL21 were shown to have the highest drug-carrying capacity and were also able to relinquish this drug-load to inhibit the proliferation of key wound pathogens; Staphylococcus epidermidis, Propionibacterium acnes, and Pseudomonas aeruginosa. XRD and FTIR analyses demonstrated that these drug molecules could be adsorbed into the interlayer space and edge groups of the Laponite® particles. LXL21-CIP composites were successfully incorporated into alginate polymer matrices through interaction of the exposed edge-groups on LXL21 and the hydroxyl groups of the alginate to produce novel nanocomposite film and foam materials. Selection of candidate materials was initially undertaken qualitatively with the support of a tissue viability nurse at the Royal Liverpool and Broadgreen University Hospitals NHS Trust. Important properties for wound-dressings such as adsorptive capacity, water vapour transmission rate, and keratinocyte compatibility were measured quantitatively and compared to materials already used for wound care in the UK. Both the film and foam materials were shown to have properties that would be beneficial for wound healing and were also able to release CIP in a controlled manner with notable activity against S. epidermidis, P. acnes, and P. aeruginosa. The nanocomposite film formulation developed in this research project showed promise for future clinical applications and future work should be undertaken to further optimise their manufacture and fully characterise their ability to support the healing of infected wounds. Although the nanocomposite foams require further research, the work presented in this thesis suggests they could also be promising materials for wound care applications.

The major goal for physicochemical screening of pharmaceuticals is to predict human drug absorption, distribution, elimination, excretion and toxicity. These are all dependent on the lipophilicity of the drug, which is expressed as a partition coefficient i.e. a measure of a drug’s preference for the lipophilic or hydrophilic phases. The most common method of determining a partition coefficient is the shake flask method using octanol and water as partitioning media. However, this system has many limitations when modeling the interaction of ionised compounds with membranes, therefore, unreliable partitioning data for many solutes has been reported. In addition to these concerns, the procedure is tedious and time consuming and requires a high level of solute and solvent purity. Micellar liquid chromatography (MLC) has been proposed as an alternative technique for measuring partition coefficients utilising surfactant aggregates, known as micelles. This thesis investigates the application of MLC in determining micelle-water partition coefficients (logPMW) of pharmaceutical compounds of varying physicochemical properties. The effect of mobile phase pH and column temperature on the partitioning of compounds was evaluated. Results revealed that partitioning of drugs solely into the micellar core was influenced by the interaction of charged and neutral species with the surface of the micelle. Furthermore, the pH of the mobile phase significantly influenced the partitioning behaviour and a good correlation of logPMW was observed with calculated distribution coefficient (logD) values. More interestingly, a significant change in partitioning was observed near the dissociation constant of each drug indicating an influence of ionised species on the association with the micelle and retention on the stationary phase. Elevated column temperatures confirmed partitioning of drugs considered in this study was enthalpically driven with a small change in the entropy of the system because of the change in the nature of hydrogen bonding. Finally, a quantitative structure property relationship was developed to evaluate biological relevance in terms of predicting skin permeability of the newly developed partition coefficient values. This study provides a better surrogate for predicting skin permeability based on an easy, fast and cheap experimental methodology, and the method holds the predictive capability for a wider population of drugs. In summary, it can be concluded that MLC has the ability to generate partition coefficient values in a shorter time with higher accuracy, and has the potential to replace the octanol-water system for pharmaceutical compounds.

Paediatric specific medicines have become increasingly researched since the introduction of paediatric investigation plan requirements in 2007. Various dosage forms continue to be investigated for their appropriateness for children, including multiparticulates. Multiparticulates are currently available as tablets, capsules, sachets and medicated spoons/straws/syringes. These presentations offer limited dose flexibility with some only providing a single fixed dose. A device capable of repeated flexible multiparticulate dosing is therefore required to exploit the inherent flexibility of the dosage form and allow for patient-specific personalised dosing. This thesis takes a user-centered approach to conceptualise multiparticulate dosing devices through qualitative participatory design studies with user groups including children, caregivers and patients. Having explored User and Formulation requirements in terms of device design, a device specification has been generated with subsequent concept generation and mechanism prototyping. The research with users provided further understanding of the different contributors to ease of use, and highlighted the importance of device simplicity, accuracy and speed of use. Exploration of the concepts of self-administration and context of use with potential paediatric MP device users discovered that self-administration was more than a single step process. Caregivers also found it difficult to provide an age at which they would be happy for their child to self-administer and highlighted various influences upon their decision including child maturity, adult supervision and child familiarity with administration. A knowledge gap surrounding the use of mass-based mechanisms to determine multiparticulate dose has also been addressed. With new knowledge surrounding MP measurement and the mechanical specifications required for a personalised dosing device presented. A case study is presented, highlighting a possible application of multiparticulates and their dosing device in Cystic Fibrosis patients. This population was selected given their familiarity with a multiparticulate like dosage form as part of their pancreatic enzyme replacement therapy. This study demonstrates how the global device requirements (presented in this work) can be refined on a case-specific basis allowing for a refined, user-centered device specification. This work provides an industry road map for user engagement, acting as a platform for future multiparticulate dosing device design and development, guiding multiparticulate formulation design and ultimately advancing the field of personalised medicines and improving health outcomes (particularly of paediatric patients).

Abstract During the course of the studies outlined in this thesis, a new approach for the synthesis of the tropane alkaloid, (±)-physoperuvine has been developed using a highly efficient one-pot tandem process which involved the Overman rearrangement and a ring closing metathesis reaction. An asymmetric one-pot tandem process has also been employed for the synthesis of the natural product, (+)-physoperuvine. This methodology was also applied to the generation of a late-stage intermediate that could be used in the synthesis of carbocyclic nucleosides, such as noraristeromycin. In the second part of this thesis, an ether-directed Pd(II)-catalysed Overman rearrangement which had previously been developed by the Sutherland group was applied in conjunction with a cross-metathesis reaction for the stereoselective synthesis of the guanidine alkaloid, (+)-monanchorin in a fourteen-step synthesis. Further employment of this process provided the first synthesis of clavaminol A, C and H from (R)-glycidol in a rapid and efficient manner. In a similar fashion, (2S,3R)-enantiomers were also synthesised from (S)-glycidol. In addition to this, using similar chemistry, an intermediate protected enone was prepared using a cross-metathesis reaction as the second key step in an approach towards the synthesis of an NO-inhibitor.

Growing attention has been given to the potential of the respiratory tract for systemic delivery of macromolecules, particularly proteins and peptides. However, limitations such as short transit time and loss of activity of some proteins and peptides in the respiratory tract need to be overcome. Consequently, the utility of controlled drug delivery systems such as liposomes as protein carriers appear promising. Unfortunately, liposomes are unstable in aqueous dispersions. Additionally, conventional liposome preparation methods such as the thin film hydration are difficult to scale-up, and also demonstrate low entrapment efficiencies for hydrophilic materials. The aim of this work was to develop novel submicron mucoadhesive liposomes entrapping the protein immunoglobulin g (IgG) using the proliposome method. Additionally, this work explored the potential of the generated liposomes for respiratory tract delivery via medical nebulisers and nasal sprays with different operating principles. Liposomes generated from the proliposome technology were multilamellar as cryo-TEM studies revealed. The generated liposomes were capable of entrapping considerable concentrations of salbutamol sulfate (59.1%), ovalbumin (43.3 %) and IgG (29.9 %). Also, the generated liposomes demonstrated superior entrapment efficiency of IgG to other liposome preparation methods (thin film and particulate- based proliposome technology). Reduction of liposome size to 400 nm and the incorporation of the mucoadhesive agent sodium alginate markedly enhanced the entrapment of IgG in liposomes (up to 50 %). The secondary structure and immunological reactivity of IgG were also maintained following its incorporation in liposomes as demonstrated by circular dichroism and microagglutination assay, respectively. Nebulisation was found to fragment liposomes as well as reduce the activity of the entrapped IgG. The degree of liposome fragmentation and loss of activity of IgG varied markedly among different medical nebulisers. Liposome size distribution and IgG immune reactivity studies elucidated that vibrating-mesh nebuliser was least disruptive to liposome structure and the immunoreactivity of the incorporated IgG was least affected following its use (retained activity of 83% versus 24% and 39% for the ultrasonic and air-jet nebulisers, respectively). Contrary to medical nebulizers, this work illustrated that all studied nasal devices preserved both the integrity of liposomes and the incorporated IgG. In conclusion, the findings of this study demonstrate potential benefits in drug delivery employing both intranasal administration and proliposome technology offer with great promise in using proliposome formulations for intranasal protein delivery.

Block copolymers of polylactide and poly( ethylene glycol) (PLA-PEG) were investigated as biodegradable drug delivery systems. They are defined by the differing molecular weight ratios of polylactide to poly( ethylene glycol). Copolymers containing more hydrophilic PEG than hydrophobic PLA per molecule self-dispersed in water giving spherical nonionic micelles. Purification by gel permeation chromatography gave two peaks. The first peak only formed micelles (the second was PLA-depleted). Analysis by dynamic light scattering (DLS) and transmission electron microscopy (TEM) gave diameters of IS.6nm and 18.9nm for 1.5:2 and 2:5 PLA-PEG micelles respectively. PLA-PEG copolymers with more PLA than PEG per molecule (4:2 and 6:2 PLA-PEG) formed "solid particles" by the solvent-precipitation method. GPC purification again gave two peaks, but smaller second peaks. DLS analysis gave diameters of 15.1 nm and 20.8nm for 4:2 and 6:2 PLA-PEG particles respectively (confirmed by TEM and atomic force microscopy (AFM)). Static secondary ion mass spectrometry and X-ray photoelectron spectroscopy showed PEG at the surface of 4:2 and 6:2 PLA-PEG in water and acetone. Stability testing to salt suggested sterically stability. Rheological measurements determined PEG chain layer thicknesses, with the thickest chain for 2:5 PLA-PEG (where PEG chain length is 5000gmol-1 compared with 2000gmol-1). Testosterone and sudan black B (SBB), were used as "model" drugs with different hydrophobicities. Ultracentrifugation sedimentation velocity studies confirmed drug incorporation. Aromatic SBB loaded readily (≥59.0%w/w) compared with steroidal testosterone <2%w/w). Loading of testosterone esters of varying hydrophobicity into PLA-PEG particles showed little difference compared to between testosterone and SBB, suggesting that aromaticity is more significant. In vitro release studies (4:2 PLA-PEG particles/SBB) showed a small burst release, then linear release to twenty eight days. In vivo studies in the rat, using a radioactive marker, demonstrated extended blood circulation times for PLA-PEG micelles during the three-hour study, with increased blood levels and lower liver uptake for 1.5:2 over 2:5 PLA-PEG micelles. PLA-PEG particles were directed to the liver.

Inhalation represents a potentially attractive delivery route for biologics, especially those designed to treat pulmonary diseases such as asthma, cystic fibrosis or lung cancer. Delivery directly to the site of action should increase local concentrations of drug, whilst reducing systemic side effects. However, there is limited knowledge regarding the mechanisms of pulmonary clearance, with gaps in understanding; where molecules are absorbed, the mechanisms involved, regional variability throughout the lung, and how to control pulmonary retention and/or facilitate cellular uptake. The work presented in this thesis details the development of a SPECT/CT imaging protocol to determine the pulmonary retention and tissue redistribution of technetium labelled antibodies and their fragments in vivo, in mice, to begin to address these knowledge gaps. The SPECT/CT imaging method was applied to a whole monoclonal murine immunoglobulin G1 (mlgG1), as well as its Fab and scFv fragments and a small protein (FN3) in order to determine whether diffusion controlled pathways were important in pulmonary antibody clearance. Additionally, the pulmonary retention of mutant mlgG1 with differing binding affinities to the murine neonatal Fc receptor (mFcRn) were assessed in order to determine whether antibody transport across the epithelium occurred via active transcytosis. It was determined that 54.4 ± 0.63 % of the total instilled dose of a whole monoclonal antibody remains in the lung over 24 hrs, with Fab and scFv fragments cleared significantly quicker with 28.7 ± 0.73 % and 34.9 ± 0.85 % respectively of the total instilled dose remaining in the lung at 24hrs. The pulmonary retention of the 11 kDa FN3 protein was also assessed with 21.0 ± 0.65 % remaining in the lungs after 24 hrs. No evidence of build up of any protein was detected in the oesophagus/stomach, suggesting little contribution by mucociliary clearance. Very little build up of whole antibody, Fab or scFv was observed in the liver or kidneys. However, very clear evidence of renal filtration of the 11 kDa fragment was observed. There was no difference in the pulmonary retention of wild type IgG and any of the mFcRn binding mutants. Additional investigation of antibody retention rates in the murine house dustmite (HOM) model of asthma, although not making use of the SPECT/CT method, showed that antibody is cleared more rapidly from the diseased lung than the normal lung. It was also shown that the expression pattern of the mFcRn receptor is the same in the normal and HDM exposed lung and so this increase in clearance rate occurs via passive diffusion controlled processes. This is most likely a result of increased paracellular transport due to disrupted mucosal barrier function. The SPECT/CT imaging method developed has proven to be a simple and reliable method to assess, non-invasively, pulmonary antibody retention in vivo. Overall it appears that antibody transport across the pulmonary epithelium occurs predominantly via diffusion controlled mechanisms, which include both paracellular transport and nonspecific transcytosis by pinocytotic routes. Additionally, in the mouse, neither receptor mediated transport by mFcRn nor mucocillary clearance is important in the pulmonary clearance of antibodies.