No description available.

No description available.

No description available.

This thesis presents the results of an ethnopharmacological survey conducted with Bedouin women in Egypt (South Eastern Desert, Siwa Oasis and North Sinai) to document their knowledge of using medicinal plants to treat women's health problems, such as dysmenorrhoea, perinatal problems, womb cleansing and urinary tract infections. Data collected revealed that the Bedouin women commonly use more than 45 different plant species. Four plant species (Haloxylon salicornicum, Achillea fragrantissima, Mentha longifolia and Acacia nilotica) were chosen for phytochemical and pharmacological investigations in this project.

Sewage treatment works (STWs) are routes through which treated wastewater effluents often containing myriads of chemicals are passed into receiving waters due to incomplete removal processes as have been identified in several studies. The current work aimed to determine the levels of these chemicals in the effluents from Stoke Bardolph STW, Nottingham and to determine the fate and behaviour of compounds by conducting degradation batch studies under different treatment conditions. The selection of representative illicit compounds; cocaine and its metabolite benzoylecgonine, heroin and its metabolites 6-monoacetylmorphine and morphine and a pharmaceutical (diazepam) was based on their presence in the STW effluent. The results obtained using solid phase extraction gas-chromatography technique (SPE-GCMS) showed thirteen compounds detected at concentrations between 1.9 and 3147 ng L-1 in effluents from Stoke Bardolph STW. Procaine, bromacil, codeine, lidocaine, ibruprofen, caffeine, nicotine and diazepam were the most abundant compounds in the final effluent with concentrations of 99.2, 1806.8, 33.5, 71.8, 3147, 213.4, 252.5 and 105.2 ng L-1, respectively. The percentage recoveries ranged from 74.5 – 109.6%, with the instrumental limits of detection (LODs) ranges of 0.2 – 12.7 ng L-1, and relative standard deviation (RSD) values of 0.6 – 4.7% were achieved for all the compounds. The batch tests enabled determination of the degradation of the compounds at different temperatures and times, using various sludge types after characterization. Removal rates of cocaine (91.0%), benzoylecgonine (90.6%), heroin (97.9%), morphine (99.7%), 6 monoacetylmorphine (93.3%) and diazepam (99.7%) were measured after 3 hours equilibration; partition coefficients (Kd) for these six substances ranged from substances ranged from substances ranged from substances ranged from substances ranged from 1.2 – 68.1 Kg L-1. The degradation of compounds at 19 ± 0.5o C was relatively greater but it still occurred slowly at 4 ± 0.5o C, at between 5 and 10%. Mass balances for two STW (Molesworth, Cambridgeshire, U.K. and Stoke Bardolph) were constructed using the removal rate data from these batch studies. Final effluent concentrations of 110.0110.0 ng L-1 (cocaine), 690.0(cocaine), 690.0 ng L-1 (benzoylecgonine), 10.0 (morphine), 80.0 ng L-1 (6 -monoacetylmorphine), and 0.7 ng L-1 (diazepam) were found in effluents after a total of 8 hour hydraulic times (8 HRT) from an initial influent concentration of 50 mg L-1. Projected influent concentrations of cocaine (14, 471 ng L-1) and benzoylecgonine (23, 907.1 ng L-1) at Stoke Bardolph were derived from back-calculating measured final effluent concentrations using this same mass balance approach. Work encompassed in this study directly measures illicit drug removal rates in laboratory studies for the first time. The application of removal rates in calculating mass balances in sewage works is an improvement over prior studies where assumptions on removal rates at STW were made.

This thesis describes the application of hyperspectral imaging (HSI) as a novel technique for the analysis of spectral data derived from image analysis of tablet breakdown during dissolution. Whilst defining the rate of release is the common output from traditional dissolution experiments, the intention of the research presented in this thesis was also to describe the physical changes occurring within the disintegrated mass during the dissolution process. The initial stages of the investigation focused on determining which wavelength ranges were most discriminatory in separating out similar polymer samples; the two wavelength ranges investigated were the visible (400-860 nm) and the near infrared (835-1650 nm). As the polymer samples were similar, comparison of the spectra for distinguishing features was unsuccessful and principal component analysis was used to separate the spectral signals. The near infrared (nIR) was shown to be the most effective wavelength range at separating s ignals due to an increased number of peaks for comparative analysis. The examination of the dissolution of paracetamol tablets produced by several different manufacturers was described in this thesis. In particular, the rate of expansion of tablet material and the identification of caffeine containing regions during tablet dissolution. The initial results tracked the expansion of the tablet within the flow cell and determined the cause of the signal attenuation affecting the results. The final experiments combined the spatial and time resolutions of the previous experiments. This system used a minimised path length to reduce signal attenuation and give spectra with enhanced spectral features. This system was able to show caffeine rich regions in the tablet during the dissolution in a caffeinated paracetamol brand, the rate of caffeine loss also being calculated. These results were then corroborated using conventional analytical techniques to establish whether HSI had robustly measured the release of a known compound during dissolution.

Since the discovery of the first prokaryotic voltage gated sodium channel (Nav) in 2001, prokaryotic Navs have been a high priority target for structural study. Prokaryotic Navs are of interest as a model system due to their homology to eukaryotic Navs, which are high value drug development targets for their roles in pain perception and neural function. While prokaryotic Navs have function and pharmacology distinct from their eukaryotic homologues, understanding their structure holds implications for drug development and for understanding diseases stemming from neuronal dysfunction. However, Navs have historically been challenging targets for structural study, resisting attempts at crystallisation until recently. In this study, expression, purification, and characterisation of a chimera of the NavBh channel and the ligand gating RCK domain from the prokaryotic potassium channel MthK has been performed. It was hypothesised that the addition of the RCK domain would improve the channel’s crystallisation potential, and create a ligand gated Nav for functional characterisation. Electrophysiological studies demonstrated that the RCK domain was capable of gating NavBh, however the chimera had reduced solubility, indicating that this chimeric fusion was not an ideal target for structural study due to low purification yields. Following this, and in light of recent studies that suggested the structure of the prokaryotic Nav C-terminus had a role in channel function, structural analysis of the C-terminus of a prokaryotic Nav homologue cloned from Bacillus alcalophilus has been performed. Synchrotron radiation circular dichroism analysis of serial C-terminal truncations demonstrated the structure of the NsvBa C-terminus consists of a helical region connected to the channel pore by a disordered neck region, despite conflicting bioinformatics predictions. This offers further support for the hypothesis that in functional Navs, the C-terminus consists of a disordered neck region connecting a coiled-coil to the base of the pore, which acts as a spring to assist in channel gating and inactivation.

A human liver microsomal bank was established and assessed for P450 drug metabolising activity. Formation of dehydrofelodipine and dieldrin by human liver microsomes correlated significantly, suggesting that common P450 isozymes were involved. Both activities also correlated with immunochemically determined P4503A concentrations. It was concluded that aldrin and felodipine represent excellent in vitro probes for P4503A activity in man. Three NSAIDs: naproxen, ibuprofen and diclofenac, exhibiting different routes of oxidative metabolism, were selected to investigate the major cytochrome P450 isozymes involved in their metabolism. The rates of formation of O-desmethylnaproxen, 4'-hydroxydiclofenac and hydroxy-/carboxyibuprofen were measured in human liver microsomes. Activities (with the exception of carboxylation of (S)- and (R)-ibuprofen) showed significant correlations with the P4502C-mediated hydroxylation of tolbutamide and did not correlate with P4503A, P4502D, P4501A and P4502C (mephenytoin hydroxylase forms) activities. Sulphaphenazole was found to inhibit the formation of metabolites of the NSAIDs. It was concluded that P4502C is the major P450 subfamily responsible for the metabolism of NSAIDs. Molecular modelling suggests that the distance of a H-bond from the site of metabolism of a substrate and the angle created between the H-bond and site of metabolism are relatively constrained, thus suggesting a tightly fitting P4502C active site. These findings aid prediction of drug substrates of P4502C in man.

No description available.

Cyclosporine (CsA) (50mg/kg daily) for 0 - 14 days caused reductions in cytochrome p-450-dependent monooxygenase activities, phase II drug metabolising enzyme activities and non-drug metabolising enzyme activities in male Sprague-Dawley rats, which appeared to be self-limiting. The chronologies and extents of these reductions varied. Decreased monooxygenase activities were accompanied by decreased NADPH-cytochrome c-reductase activities. No isozyme-specific effect was evident and there was no direct correlation of drug metabolising activities with nephrotoxicity (which was progressive). The wide-ranging effects of CsA on membrane-bound drug and non-drug metabolising enzyme activities suggests an effect on membrane properties may be responsible. CsA did not decrease cytochrome P-450-dependent monooxygenase activities in female rats, nor was there any visual signs of CsA toxicity. A method for in vitro generation of CsA metabolites, a solvent extraction system and an HPLC system for separation of the metabolites was undertaken. The metabolite profiles produced on incubation of CsA with liver microsomes prepared from untreated and CsA-pretreated rats, rats pretreated with inducers of cytochrome P-450 (Phenobarbitone (PB), 3-methylcholanthrene (3-MC) and pregnenelone 16 -carbonitrile (PCN)) and human microsomes were compared. Michaelis-Menten kinetics for CsA disappearance were calculated. All microsome types metabolised CsA with the exception of CsA-pretreated rats. Biphasic kinetics were produced by orally dosed PB-induced microsomes, PCN-induced, control rat microsomes and human microsomes. Monophasic kinetics were obtained for a further orally dosed PB-induced microsome sample and PB (80mg/kg ip). CsA metabolism was induced 2.5 - 3.0 fold by PB and PCN microsomes compared with control rat microsomes. Human microsomes metabolised CsA faster than all rat microsomes. Metabolite 1 was the major metabolite produced by all microsome types. Only low levels of secondary and tertiary metabolites were produced by rat microsomes, even when sufficient levels of primary metabolites were present, suggesting that CsA and its metabolites may be metabolised by the same enzyme. Metabolites 17 and 18 were produced by all microsome types. Metabolites B and 21 were produced only by PB and PCN-induced rat microsomes and by human microsomes.