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Cancer pain is one of the most common and challenging symptoms faced in the palliative care. It can be breakthrough pain, which requires a fast-acting opioid formulation, or chronic pain, which is clinically controlled with 24 h opioid medications. Due to the significant risk of opioid misuse and diversion, infection, overdose, bodily invasiveness, movement restriction, and the high cost of hospitalisation, current and emerging delivery systems are unable to provide opioids efficiently to control cancer pain. This study proposed a novel opioid delivery system for the treatment of cancer pain based on mesoporous silica nanoparticles (MSNs), gold nanoparticles (AuNPs), and the thermo-responsive poly (N-isopropyl arylamide) (PNIPAM). Because of the complexity of the proposed system, this work concentrated on the core of the triggered system, which is the quantification and characterisation of drug entrapment and in vitro drug release in response to thermal triggers. The goal was to create a PNIPAM-grafted MPS-MCM-41 for thermosensitive TDDS for pain control. Toward achieving this goal, ideal characteristics of delivery systems for treating cancer pain were first recommended after a comprehensive evaluation of the present delivery systems used for cancer pain control. After that, a thorough investigation was carried out to address the challenges with drug entrapment into MSNs, including the measurement technique and verifying that the drug was loaded inside the silica nanoparticles' mesopores. As an alternative to the time-consuming, expensive, and highly variable standard method of high-performance liquid chromatography (HPLC), a quick, sensitive, and inexpensive analytical methodology based on thermogravimetric analysis (TGA) was developed. A novel way of characterising the drug entrapment method of adsorption and incipient wetness impregnation for drug entrapment into the pores of MSNs was developed utilising differential scanning calorimetry (DSC) and an in vitro dissolution study. Subsequently, the hybrid PNIPAM-grafted MPS-MCM-41 was synthesised, and its properties, including the thermo-responsive triggered release behaviour, were studied. The results demonstrated that the proposed TGA approach was a quick (60 min), sensitive (limit of detection = 0.77 %, w/w), and economical substitute for the HPLC. The results of the multiple comparison analysis indicate that there was no significant (p > 0.05) difference in the drug entrapment measurements obtained using the two methods of TGA and HPLC. The results from the DSC and the in vitro dissolution study showed a high crystallinity degree for the MSNs loaded with the adsorption method with a slower release profile, compared to a low degree of crystallinity with a faster release profile with the incipient wetness method, implying the presence of an amorphous drug inside the silica pores. The thermo-responsive release behaviour of the hybrid PNIPAM-grafted MPS-MCM-41 was confirmed, which showed a faster rate of release at temperatures above the polymer transition temperature, at 40 °C and 50°C, compared to that below the transition temperature, at 25 °C. The cumulative percentages of drug released were 37.1 ± 5.1 %, and 38.6 ± 4.2 %, at 40 ºC, and 50 ºC, respectively, compared to 21.3 ± 5.5 % at 25 ºC. This discovery suggests that the hybrid PNIPAM-grafted MPS-MCM-41 may be able to construct a thermo-responsive TDDS that can serve as a core platform for a photothermal TDDS for cancer pain control.

Introduction: Lateral flow immunoassays (LFA) are routinely used to detect illicit drugs in biological matrices. Most recently, latent fingerprints (LFPs) have been analysed using this method. There is a lack of screening tests that identify MDMA(ecstasy) despite it being used by 2.6 million people in Europe and 524,000 in England and Wales. MDMA (pKa 9.9) has been shown to be excreted in sweat. This thesis explored the utility of LFPs as a biological matrix for screening for MDMA in the field via a LFA as a Point-of-Care test (POCT). Method: The Ridgeway (Intelligent Fingerprinting Ltd., UK) was employed to quantify LFPs and they were further characterised using ATR-FTIR to measure LFP mass and composition. The Ridgeway was used to investigate fingermarks sampling methods and variables known to influence sweat production including deposition pressure,environmental conditions and certain drugs. An optimised plate immunoassay was used to establish a suitable binding pair (Anti-MDMA and BSA-MDMA). Further characterisation included establishing an ideal Alexa Fluor 488 TFP:Anti-MDMA ratio and confirming cross-reactants. Results were validated with Surface Plasmon Resonance (SPR). A LFA suitable for MDMA detection using LFPs was achieved by testing different antibody binding concentrations against different extraction buffer compositions. Optimisation of the LFA identified: cross-reactants, cartridge run-time and cut-off level. Fluorescent LFA signals were measured using Intelligent Fingerprinting Reader 1000 (Intelligent Fingerprinting Ltd., UK). Results: A significant positive correlation was calculated between LFP mass and Ridgeway score [p=0.02] advising a relationship between the two measurements. Higher Ridgeway scores corresponded with sebaceous LFPs after ATR-FTIR analysis. An optimal sampling method was determined as: cumulative deposition of10 LFPs [p<0.1] and either hand can be used. To collect eccrine only LFPs, Carex soap with lint free tissue were most suitable [p<0.01] compared to antibacterial handgel. Different environmental climates did not change the sample quantity deposited for both natural and eccrine LFPs. Drug use, including methadone, significantly increased Ridgeway scores in the addict population versus the control population[p<0.01]. Comparable LFPs were collected via consistent deposition pressure (300 -400 g) and glass deposition surface. Both plate assay and SPR results confirmed the binding pairs' suitability for the MDMA LFA. Monoclonal Anti-MDMA detected MDMA at 0.15 ng/mL and KD values of 0.3 and 0.5 nM were calculated, respectively. A ratio of 7.3:1 was calculated as the ideal labelling ratio. A sensitive LFA, which produced a sharp-drop in signal, was designed using an extraction buffer coupled with 20 ng Anti-MDMA and 120 µg/mLBSA-MDMA. This established a cut-off value of 60 pg in 10 µL which generated excellent accuracy (0.98), sensitivity (1.0) and specificity (0.95). Immunoassay methods recognised Methylenedioxy-N-ethylamphetamine and para-Methoxy-Nmethylamphetamine as key cross-reactants at 55 pg in 10 µL. Conclusion: A sensitive MDMA LFA was successfully designed to identify MDMA inLFPs at a cut-off value of 60 pg in 10 µL for use in drug screening. For this purpose,an optimal LFP collection method was also established.

Radiotherapy is a life-saving treatment for head and neck cancers, but almost 100% of patients develop dry mouth (xerostomia) because of radiation-induced damage to their salivary glands. Local delivery direct to the buccal mucosa has the potential to provide a rapid onset of drug action within the buccal mucosa while sparing systemic drug exposure and off-target effects. Therefore, the aim of this research was to produce a novel buccal fast disintegrating freeze-dried pilocarpine HCl tablet for the treatment of xerostomia. The chemical stability of pilocarpine HCl was investigated thoroughly for the determination of the formulation strategy following the 5-stage melting determination approach developed in this project. Pilocarpine HCl was characterised using powder X-ray diffraction (PXRD), optical differential scanning calorimetry (DSC), thermogravimetric analyser (TGA), high-pressure liquid chromatography (HPLC), DSC, back titration, thermogravimetric analyser – mass spectrometer (TGA-MS), liquid chromatographymass spectrometry (LC-MS) and polarimetry. The results indicated that pilocarpine HCl underdoes disprportionation during melting, and the characterisation of the newly discovered solid-state epimerisation showed that at the onset of melting of the drug is nearly a racemic mixture of pilocarpine HCl with its inactive form isopilocarpine HCl. Therefore, freeze-drying as a formulation strategy was a suitable technique to maintain the chemical stability of pilocarpine HCl. Freeze-dried tablets were successfully produced containing 11% (w/w) sodium bicarbonate, 33% (w/w) gelatin and 56% (w/w) of mannitol and 5 mg of pilocarpine HCl. All batches passed the BP quality control tests. The average weight, width, length and drug content were 22.1 ± 0.6 mg, 13.4 ± 0.3 mm, 23.1. ± 0.4 mm and 4.8 ± 0.01 mg, respectively (n=6, ± SD). A novel quality control in-vitro digital assay was designed to measure the disintegration time of the buccal tablets. Results showed that freeze-dried pilocarpine HCl tablets were fully disintegrated, in 0.7, 0.1 and 0.05 mL of the phosphate buffer saline at 37°C within 10 seconds (n=3). In conclusion, the novel aspects of this PhD project were; 1) a thorough investigation of the stability of pilocarpine HCl revealed an unreported disproportionation and novel solid-state epimerisation of the API; 2) a new in-vitro digital image disintegration assay was developed as a quality control test for the measurement of disintegration time of fast disintegrating tablets, and 3) a unique freeze-dried formulation of buccal pilocarpine HCl was successfully designed.

Background: Dissolution testing has been proposed as a sensitive and discriminatory in vitro test for evaluating the quality or similarity of inhaled pharmaceuticals. This has led to a number of bespoke respirable particle collection and dissolution techniques being developed by academic and industrial pharmaceutical scientists. However, each comes with limitations and there is no standard or universal dissolution system for orally inhaled products. A dissolution test system would ideally reproduce conditions that represent the in vivo lung environment and would have the potential to be used for both quality control purposes and as a predictive in vitro-in vivo correlation tool. However, test systems proposed to date do not meet these criteria fully, for example many have not utilised media designed to simulate respiratory tract lung fluid (RTLF). Dissolution methodology should fulfil requirements such as simplicity, reproducibility, ease of handling, robustness and be able to discriminate differences between inhaler batch, product and formulation types. Aim: The aim of this thesis was to develop dissolution methods for OIPs by identifying the critical attributes and shortcomings of current systems and designing and evaluating improved systems using fluticasone propionate (FP) as the model drug. Methods: Two dissolution systems were evaluated: a Next Generation Impactor/Rotating paddle system and a Twin stage Impinger/Transwell® system. A novel simulated lung fluid (SLF) based on the major components of human RTLF was manufactured and characterised in terms of its physicochemical properties and stability in solution and after freeze-drying. The solubility and dissolution of inhaled drugs, including FP, were evaluated in the SLF and compared to other media. The impact of using SLF as a dissolution media was evaluated in a biorelevant dissolution system, the novel DissolvIt® system, and an in-silico PBPK model was developed and applied to evaluate the impact of in vitro data on drug pharmacokinetics and enable comparison with in vivo data. To develop the TSI/Transwell system as a biorelevant system, a Design of Experiments (DOE) approach was used to identify the influence of temperature, stirring and the solubilising capacity of dissolution media on dissolution profiles of FP. Finally, a biorelevant methodology was used to compare the dissolution of nebulised suspension and microemulsion formulations to other inhaled formulations. Results: Both dissolution systems were simple and easy to handle, producing reproducible data. Although the novel NGI/rotating paddle system was a convenient starting point for quality control purposes, the TSI/Transwell system was more amenable to development as a biorelevant technique as it was able to mimic the low fluid volume of RTLF and could be used with lung fluid simulants that are expensive and only available in limited volume. A SLF of biorelevant composition, consisting of proteins (albumin, transferrin and IgG), lipids (DPPC, DPPG and cholesterol) and antioxidants, was characterised. It was shown to possess physiochemical properties comparable to those of RTLF, such as being an isotonic solution with a physiological pH of 7.2, viscosity of 1.138 x 10-3 Pa s, conductivity of 14.5 mS/m, surface tension of 54.9 mN/m and density of 0.999 g/cm3.The simulant was stable for 24 and 48 h at 37 and 20°C and for 14 days at 4°C and when freeze-dried. A novel and sensitive solid phase extraction and LC-MS/MS technique for the assay of FP was established and validated successfully to quantify the drug in low concentrations in biological matrices, in picogram concentrations. In the DissolvIt system the use of SLF as a dissolution medium did not impact on dissolution profiles compared to the standard polymer solution (P > 0.05), but DOE using the TSI/Transwell system found solubilising capacity of the medium to be a major factor. Biorelevant conditions assigned as a dissolution medium of 0.1% w/v SDS in PBS (providing the same solubilising capacity as SLF), temperature 37°C and stirring rate 15 rpm. These biorelevant dissolution test conditions indicated that the dissolution of FP from a novel microemulsion formulation reached approximately 70% (almost double) over the 8 h experiment, compared to the dissolution of FP from the Flixotide suspension formulation (P < 0.05). Conclusion: A simulated lung fluid has been developed for use in a dissolution system tailored to orally inhaled products. The dissolution technique is sensitive to temperature, stirring and the solubilising capacity of the dissolution medium and in preliminary tests has shown promise in discriminating between different fluticasone inhaler products and formulations.

Introduction: Methadone hydrochloride (MDN) is an effective pharmacological substitution treatment for opioids dependence, adopted in different countries as methadone maintenance treatment (MMT) programmes. However, MDN can exacerbate the addiction problem if it is abused and injected intravenously, and the frequent visits to the MMT centres can reduce patient compliance. The overall aim of this study is to develop a novel extended-release capsule of MDN using the sol-gel silica (SGS) technique that has the potential to counteract medication-tampering techniques and associated health risks and reduce the frequent visits to MMT centres. Methods: For MDN recrystallisation, a closed container method (CCM) and hot-stage method (HSM) were conducted, and MDN crystals were characterised using the polarised light microscope (PLM). MDN crystal thickness was determined by scanning electron microscopy (SEM) and confocal microscopy (CM) to establish a relationship between MDN crystals thickness and their birefringence colours using the Michel-Levy Birefringence Colour Chart. The experimental series was continued to produce novel silica-based MDN formulations A and B capsules by adding MDN powder at the end and beginning of the SGS process, respectively. The silica-based MDN formulations were characterised by Fourier transform infrared (FT-IR), SEM, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), PLM and mean grey value (MGV) analyses. The in vitro release studies (n=3) for the silica-based MDN formulations and pure MDN capsules were conducted in a phosphate buffer solution (pH= 7.2) for 7 days. Stability studies were conducted for 1 month by keeping the silica-based MDN capsules under 25°C and 57% RH. Results: The optimal method to produce large numbers of MDN crystals was the CCM, and MDN crystals were characterised as diamond shaped with an intrinsic angle of 62o. The SEM surpassed the CM in measuring MDN crystal thickness, and Mann-Whitney U Test showed statistically significant differences between SEM and confocal thickness measurements (U= 1283, p < 0.05) as the SEM exhibited thinner diamond crystals (6.62 ± 2.9 µm) than the CM measurements (9.6 ± 4.6µm). According to the Michel-Levey birefringence colour chart (using the SEM mean thickness of MDN crystals and their retardation value of 428 nm), most of MDN crystals demonstrated a yellow colour. The FT-IR, SEM, DSC, MGV and PLM analyses of both silica-based MDN formulations revealed that MDN was successfully incorporated inside the silica network producing amorphous material (with no appearance of the melting peak of pure MDN at 233.4°C) with evidence of no physical or chemical interaction between sol-gel silica and MDN. However, the TGA analysis revealed a significantly greater amount of MDN was loaded inside the silica-based MDN formulation B compared to A (t = 2.80, p = 0.009, n=6), as 28.3 ± 0.6 mg of MDN was loaded in the former while 25.6 ± 0.7 mg in the latter. In addition, the silica-based MDN formulation B released 10% more MDN after 7 days than formulation A, and both formulations were stable when stored for 1 month under 57% RH and 25°C. Conclusion: The novel combined use of SEM and PLM techniques shows a potential for the identification of MDN in forensic science as it established a range of birefringence colours of MDN crystals. Moreover, the new silica-based MDN formulation B can help to deter MDN abuse and increase patient adherence to MMT due to its potential to sustain MDN release and reduce the frequent visits to MDN treatment centres.

Specific ligand targeting has been shown to facilitate drug transport across biological membranes. The aim of this PhD was to investigate whether ion-pairing a drug (theophylline) with a polyamine transporter system (PTS) substrate (polyamine) could actively target drug delivery into the lungs from the pulmonary circulation. To try and achieve this, cyclodextrins were used in a co-solvent to engineer a physically stable cyclodextrin-ion-pair complex. FT-IR and HPLC binding assays showed that theophylline (THE) bound most tightly to spermine (SP) (THE-SP: pKFT-IR = 1.96 ± 0.04, pKHPLC = 2.81 ± 0.06) than to spermidine (SPD) (THE-SPD: pKFT-IR = 1.93 ± 0.05, pKHPLC = 2.79 ± 0.065) followed by ethylenediamine (EDA) (THE-EDA: pKFT-IR = 1.43 ± 0.02, pKHPLC = 2.49 ± 0.05) and the least with ethylamine (EA) (THE-EA: pKFT-IR = 1.32 ± 0.04, pKHPLC = 2.43 ± 0.042). Ion-pairing theophylline with the counter-ions significantly increased the drug’s solubility and reduced its lipophilicity. The formation of 1:1 cyclodextrin/[theophylline-spermine] ion-pair complexes were confirmed by NMR. Reducing the dielectric constant of the vehicle was found to increase the binding affinity of theophylline to spermine (pKTHE-SP in 70 % PG: pKTHE-SP = 2.11 + 0.045 > pKTHE-SP in 10% EtOH: 2.05 + 0.053 > pKTHE-SP in water: 1.96 + 0.06) when assayed with FT-IR. However, it was found that the ion-pair, regardless of the vehicle used or when complexed with cyclodextrins, dissociated rapidly when the pH of the solution was dropped to 7.4. The theophylline-spermine uptake in A549 showed that the PTS was involved in the membrane transport of the drug. In addition, a sustained delivery of theophylline was achieved when cyclodextrin was complexed with the ion-pair, which suggested cyclodextrins could stabilize the ion-pair association. Hence, a cyclodextrin-theophylline-spermine complex described herein represents a potential for lung targeting delivery.

A commonly used approach for the improvement of dissolution and disintegration is to render a poorly soluble drug into its amorphous or disordered form. However, such amorphous materials are physically unstable and are difficult to formulate into oral dosage forms due to their sensitivity to the physical and thermal processes that are involved in production. The first aim of work presented here was to produce the amorphous form of a drug in-situ within a capsule. The second aim was to develop a predominantly amorphous freeze-dried buccal tablet for the rapid delivery of emergency medicine. Nifedipine and naloxone were used as the test compounds to achieve aims 1 and 2 respectively. Nifedipine and polyvinylpyrrolidone K10 (PVP) were dissolved in tert-butanol at 37 oC to provide a range of drug to polymer ratios. These solutions were dispensed into gelatin capsules, freeze-dried, sealed and packaged in amber vials under nitrogen. The nifedipine content was maintained at 10 mg per capsule, but the PVP concentration was increased from 0 to 90% w/w. Differential scanning calorimetry, infra-red spectroscopy, polarization light microscopy and USP in vitro dissolution were used to optimise and characterise drug-polymer interactions in the freeze-dried formulations. The optimised in-situ freeze-dried capsule formulation (10% w/w nifedipine in PVP) formed a predominantly amorphous and porous formulation, with 3 months shelf life at 40 oC, stabilised by drug-polymer hydrogen bond intermolecular interactions. Drug released in vitro dissolution by optimized formulation reached 80% in < 6 min, approximately half the time required by the marketed nifedipine formulation. Excipients and naloxone HCl were dissolved in aqueous solution and dispensed into aluminium blisters to be freeze-dried. The optimised tablet composition (mannitol 24% w/v, gelatin 65% w/v, sodium bicarbonate 11% w/v and naloxone 800 μg) formed stable predominantly amorphous tablets. Sodium bicarbonate was found to be essential in preventing mannitol from recrystallizing in freeze concentrates, while high gelatin to mannitol ratio ensured the stability of amorphous mannitol during and after freeze-drying. A novel disintegration assay was developed to represent conditions in the buccal cavity: i.e. temperature 33-37 oC, dissolution volumes (0.1-0.7mL), mucin containing disintegration medium. The amorphous tablet has shown to disintegrate in less than 10 s. The disintegration assay was discriminatory for quality control purposes and has potential for future development as an assay to predict in vivo performance. In conclusion, rapidly dissolving tablets have been developed which are suitable for proof-of-concept clinical trial in humans to determine the pharmacokinetics of naloxone delivered via the buccal route.