Pharmacists have been identified to address the increasing workload in United Kingdom (UK) general practice. A pilot has been commissioned by National Health Service England (NHSE) to upskill pharmacists for this purpose. Evaluation is underway and early reports indicate that there have been integration issues. The value of pharmacists working in general practice and the level of training required for the role are not fully understood. The research reported in this thesis was started before the NHSE pilot. It was conducted to understand the background of Clinical Commissioning Group (CCG) practice pharmacists (PPs), and their interactions with stakeholders. The rationale was to provide an insight into their working relationships and to generate recommendations to support the integration of pharmacists into general practice. The project was conducted in four CCGs in the West Midlands in 2014 using an interpretive/collective case study approach incorporating mixed methods for data collection. Quantitative data was collected on the background, employment and activities of PPs. Qualitative data was collected on stakeholders’ views of the CCG PP role from commissioners, general practitioners (GPs), and patients. Different commissioning models for PPs were studied to provide a deeper understanding of PPs’ interactions. The workload problems in general practice subsequently modified the focus of this thesis to determine the value of PPs to general practice, the level of training required and to propose a model for the integration of pharmacists into UK general practice. The thesis study identified some determinants of integration found in previously published studies but also discovered new areas specific to the integration of pharmacists into UK general practice. These areas can be grouped into three elements - the pharmacist’s skills and attributes, practice level facilitation and national level support. They are presented as a unique Model for the Successful Integration of Pharmacists into General Practice Teams.

Background: Kv2.1 and TASK-1 channels are two main contributors of K+ currents in pulmonary artery smooth muscle cells (PASMC). Dysregulation of these channels has been implicated in the pathogenesis of pulmonary hypertension (PH). This thesis aims to delve deeper into the implications of the regulation of Kv2.1 by Kv9.3 in PH. Another subject of interest would be whether NADPH oxidase type 4 (Nox4), one of the major reactive oxygen species (ROS) producers in the PASMC, modulates Kv2.1, Kv9.3, and TASK-1 channels. The effects of several redox agents are also investigated as potential modulators of Kv2.1, Kv9.3, and TASK-1. In addition, this thesis also examined the effect of a Kv2-channel blocker, stromatoxin, on Kv2.1 and Kv9.3. Finally, since amphoterin-induced gene and open reading frame (AMIGO) proteins have recently been shown as novel Kv2.1-interacting partners, their effects on Kv2.1 and/or Kv9.3 are also explored in this study. Experimental approach: Whole-cell patch clamp electrophysiology was used to measure currents of the ion channels expressed in modified tsA-201 cells, in the absence and presence of Nox4 AMIGO and other regulatory molecules. Immunohistochemistry was deployed to visualize the distribution of Kv2.1 and Kv9.3 proteins in the rat lungs and hearts. Key results and Conclusions: This study supports the findings that Kv9.3 regulates Kv2.1 by increasing the current amplitude, shifting the activation threshold to a more negative voltage range, and prolonging the slow component of time constant of deactivation. These effects could be beneficial in PH as this would mean cells could be brought back to its resting membrane potential faster and the transduction of the next action potential can be delayed. Kv2.1 and Kv9.3 have also been detected at the endothelium and PASMC in rat lungs and hearts, further substantiating the claim that these channels are potential players in regulating PH. AMIGO1 and AMIGO2 proteins are confirmed as regulators of Kv2.1 and Kv9.3 proteins. Nox4 does not regulate Kv2.1, Kv9.3, and TASK-1 channels expressed in tsA-201 cells. While hydrogen peroxide (H2O2) does not have any effect on Kv2.1 and Kv9.3, it abolished the current reduction effect of AMIGO2 on Kv2.1/Kv9.3. Other redox agents used in this study such as dithiothreitol (DTT), 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB), and chloramine T (Ch-T) are not modulators of these channels expressed in tsA-201 cells. The lack of effect from Nox4 and these redox agents could suggest that the redox regulation of different Nox subunit/Kv channels combination varies for different cell types due to the different regulatory proteins present in different heterologous expression systems. As with the case of H2O2 and AMIGO2, it is likely that the regulatory proteins, which could facilitate the hypoxia-sensing properties of Nox4 and the effects of the redox agents on the ion channels, are missing in our heterologous expression system, compared with other host cells.

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Risk of cardiac conduction slowing (QRS/PR interval prolongations in monitored electrocardiograms) is assessed in nonclinical studies, where the current AstraZeneca strategy involves ensuring high margins to in vitro effects and statistical tests to identify in vivo effects. This thesis aims to improve QRS/PR risk assessment using pharmacokinetic-pharmacodynamic modelling for describing QRS/PR effects and evaluating translation to human effects. Data for six compounds were collected from the literature and previously performed in vitro (sodium/calcium channel), in vivo (guinea pig/dog) and clinical AstraZeneca studies. Mathematical models were developed and evaluated to describe and compare effects across compounds and species. Key results were that proportional drug effect models often suffice for small QRS/PR changes (up to 20%), while larger effects require nonlinear models. Heartrate correction and circadian rhythm models reduced residuals primarily for describing baseline PR intervals, with highest impact in humans followed by dogs and guinea pigs. Meaningful (10%) human QRS/PR changes correlated to low levels of sodium channel block (3-7%) and calcium channel binding (13-21%) and to small effects in guinea pigs and dogs (QRS 2.3-4.6% and PR 2.3-10%). This suggests that worst case human effects can be predicted by assuming four times greater effects at the same concentration from dog/guinea pig. Small changes in vitro and in vivo consistently translate to meaningful PR/QRS changes in humans across compounds. Accurate characterisation of concentration-effect relationships therefore require a model-based approach. Although the presented work is limited by the small number of investigated compounds, it provides a starting point for predicting human risk using routine QRS/PR data to improve the safety of new drugs.

This thesis investigates the effect of various physical and chemical surface modification methods on the permeation of topically applied pharmaceutical compounds through poly(dimethylsiloxane) (PDMS), a polymer frequently employed as a model barrier in in vitro skin permeation studies. Such studies are essential for safety, risk assessment, and quality control purposes, in addition to assisting in the design and development of efficacious topically applied medicines. The commercial availability, legal status, ease of handling, and the reproducibility of the permeation data associated with polymeric skin mimics renders them an attractive alternative to biological tissue. However, over-predictions of percutaneous absorption observed following the use of such membranes are a significant disadvantage when attempting to obtain quantitative toxicological data. Accordingly, the aims of the work presented in this thesis were to both reduce the permeability of PDMS to pharmaceutical compounds, and to increase correlation between permeation data obtained using the synthetic substitute and data obtained similarly using suitable biological tissue. Primarily, the potential of an air plasma pre-treatment to produce a lamellae-type structure in PDMS, endeavouring to more accurately model the architectural, physical, and chemical properties of the human stratum corneum, was investigated. Reductions in the permeability coefficient of up to 54.4 % were observed, rendering the modified system promising. Correlation analysis revealed an increase in correlation between the data collected using the modified synthetic substitute (R 2 = 0.86) and a selfcollated library of literature-derived epidermal tissue permeability data, relating to eighteen compounds and spanning a range of typical penetrants, compared to similar analysis using data obtained using the native substitute ( R 2 = 0.75), suggesting an increase in the predictive capability. It was hypothesised that an N2 plasma treatment may provide suitable surface functional groups on the PDMS substrate, namely amine groups, for the covalent attachment of biomolecules via an N,N'- dicylohexylcarbodiimide (DCC) coupling reaction, enabling the production of a skin mimic displaying enhanced biorelevance. Therefore, the effect of an N2 plasma pre-treatment on the permeation of a subset of the eighteen compounds investigated. It was found that the N2 plasma pre-treatment was advantageous in terms of offering a greater reduction in permeability, since longer treatment times could be employed i.e. reductions of up to 61.8 % were observed. However, significant surface oxidation was still observed, with only a marginal increase in nitrogen containing functionalities compared with the air plasma analogue i.e. 0.31 %. Furthermore, the treatment did not offer any additional increase in correlation between epidermal-derived data than previously observed. Further chemical methods of biomolecule attachment were pursued for use in the development of a lipidproteinaceous bilayer model, initiated in both cases by surface amination using an alkoxysilane. This was followed by a DCC coupling to an amino acid in the former approach, and use of a glutaraldehyde III linker molecule to attach the same amino acid, namely lysine, in the latter approach. In either case, no further reductions in the permeation of the pharmaceutical compounds tested were observed, with respect to that through plasma treated PDMS. In summary, the air plasma treatment of PDMS was found to be a promising approach to simultaneously reducing the permeability of a silicone skin mimic and increasing correlation with data obtained in similar studies employing biological tissue. Further, the covalent coupling of biomolecules to the surface of PDMS following surface amine group generation, via both plasma and wet chemical methods, appeared not to compromise the integrity the PDMS membranes relating to such applications, rendering the techniques compatible with the production of biorelevant semi-synthetic skin mimics.

Enhancement of the drug efficacy and elimination of the side effects resulting from drug overdoses are an essential aspect in drug therapy. To achieve these demands two general guidelines have been used; producing new drugs with higher selectivity and therefore less side effects and improving controlled/sustained drug delivery agents based on polymers. Thus, the relationship between the active pharmaceutical ingredient and the polymeric system is important in the development of a drug delivery system and several considerations need to be taken in to account, for example the polymer should be biocompatible, biodegradable, and non-toxic and physiochemical properties. Because mucus is the first barrier with which food and drugs can interact with and diffuse through to be absorbed and enter the circulatory system, characterisation of mucin is an essential step towards establishing suitable pharmaceutical excipients. Therefore, the aim of the present study was to investigate the potential to construct and study drug delivery systems based on polysaccharides. The physicochemical characterisation of extensively degraded pig gastric mucin was studied and revealed that this type of mucin contains: protein, carbohydrate (Fuc, Gal, GalN, GlcN) and sialic acid, which provides the negative charges that becomes progressively stronger with increasing pH. The measurements of viscosity vs. shear rate showed that mucin has a shear thinning behaviour and a relatively low viscosity which is consistent with a high critical overlap concentration (c*), small hydrodynamic size and hence compact structure. The insight in to the compositional, hydrodynamic and viscoelastic properties support the understanding of mucin interactions with polysaccharide based drug delivery systems. Several polysaccharides including chitosan (Cs), two grade of alginates; high guluronate alginate (HGA) and low guluronate alginate (LGA) (which differ in structural conformation) and two kinds of pectin; high methoxyl pectin (HMP) and low methoxyl pectin (LMP) (with different degrees of esterification) have been characterised. The structure of these polysaccharides as powder have been studied; Fourier transform infrared spectroscopy ) findings indicate the structure and the function group for each polysaccharide whereas powder X-ray diffraction measurements displays that all the polysaccharide which were analysed are amorphous in nature except LMP which has a number of sharp crystalline peaks. In addition, solution properties of these polysaccharides such as zeta potential and intrinsic viscosity were investigated at several ionic strengths and pH. Furthermore the molecular weights were evaluated based on intrinsic viscosity and the Smidsrød-Haug stiffness parameter (B) and intrinsic persistence length (Lp) were estimated using the novel ionic strength dependency of zeta potential method and intrinsic viscosity (traditional method). The interaction between polysaccharides and pig gastric mucin were evaluated based on relative viscosity. It has been suggested that polysaccharide–mucin interactions are not only driven by electrostatic forces, but also by the molecular weight, conformation and flexibility of the polymer also played significant roles. As the mucin-HGA system displayed exceptionally high viscosity, the viscoelastic properties of this system were extensively studied. The mechanical spectra of the mucin-HGA blends indicate that with the exception of the system involving only HGA (0 % mucin) and 60 % mucin, all mixtures including mucin itself displayed typical ‘weak gel’ rheological behaviour and the gel became stronger with decreasing HGA content in the system. Moreover 80 % of mucin was successfully encapsulated within phospholipids bilayer using liposomal encapsulation technology. The liposomal vesicles with encapsulated mucin display larger sizes than the control vesicles (prepared in DI water) this may be due to the electrostatic interaction between mucin molecules and phospholipid which is the main component the vesicles. In the final part of the thesis the hydrogel containing chitosan and naturally occurring polyanions and its potential for drug release were studied. Chitosan - polyanion (HGA, LGA, HMP and LMP) hydrogels complexes were successfully prepared (in acetate buffer 0.05M, 4.3 pH) at various ratios (10 %, 30 %, 50 %, 70 % 90 % of Cs) using the ionotropic gelation method. The freeze dried hydrogels were characterized by FT-IR and XRD and the results confirmed the electrostatic interactions between chitosan and polyanions at all ratios and percentage yield of hydrogel ζ and ηsp results of the supernatant was determined and it was found that the optimum ratios 3:7 and 1:1 of chitosan-pectins and chitosan-alginates respectively. The hydrogels of ideal ratios were studied by determining zeta potential, particles size, water uptake, morphology by scanning electron microscopy for freeze dried hydrogels and optical microscopy analysis for homogenous suspension. In addition, dynamic small deformation oscillatory measurements and adhesion property were studied. Finally, ibuprofen was successfully encapsulated by the chitosan-polyanion hydrogel complexes and the encapsulation efficiency of the formulations was calculated. Finally the drug release behaviour of the formulations was in vitro assessed over the time. The findings demonstrated that HMP and LGA hydrogels displayed the highest percentage of retained ibuprofen followed by HGA and LMP. This could be attributed to the fibrous appearance small size of pores which may impedes movements of entrapped molecules.