Malaria is currently one of the most imperative parasitic diseases in developing countries. Artesunate has a short half-life, low aqueous solubility and resultant poor and erratic absorption upon oral administration, which translate to low bioavailability. Mefloquine is eliminated slowly with a terminal elimination half-life of approximately 20 days and has neuropsychiatric side effects. Novel drug delivery systems have been utilised to optimise chemotherapy with currently available antimalarial drugs. Pheroid™ technology is a patented drug delivery system which has the ability to capture, transport and deliver pharmaceutical compounds. Pheroid™ technology may play a key role in ensuring effective delivery and enhanced bioavailability of novel antimalarial drugs. The aim of this study was to evaluate the possible efficacy and bioavailability enhancement of the selected antimalarial drugs, artesunate and mefloquine, in combination with Pheroid™ vesicles. The in vitro efficacy of artesunate and mefloquine co-formulated in the oil phase of Pheroid™ vesicles and entrapped in Pheroid™ vesicles 24 hours after manufacturing were investigated against a 3D7 chloroquine-sensitive strain of Plasmodium falciparum. Parasitemia (%) was quantified with flow cytometry after incubation periods of 48 and 72 hours. Drug sensitivity was expressed as 50% inhibitory concentration (IC50) values. An in vivo bioavailability study with artesunate and mefloquine was also conducted in combination with Pheroid™ vesicles, using a mouse model. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to analyse the drug levels. C57 BL6 mice were used during this study. The selected antimalarial drugs were administered at a dose of 20 mg/kg with an oral gavage tube. Blood samples were collected by means of tail bleeding. The in vitro drug sensitivity assays revealed that artesunate, co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period, decreased the IC50 concentration significantly by 90%. Extending the incubation period to 72 hours decreased the IC50 concentration of artesunate, also co-formulated in the oil phase of Pheroid ™ vesicles significantly by 72%. No statistically significant differences between the reference and Pheroid™ vesicle groups were achieved when artesunate was entrapped 24 hours after manufacturing of Pheroid™ vesicles. Mefloquine co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period decreased the IC50 concentration by 36%. Extending the incubation period to 72 hours increased the efficacy of the Pheroid™ vesicles and the IC50 concentration was significantly decreased by 51%. In contrast with the results obtained with artesunate, entrapment of mefloquine in Pheroid™ vesicles 24 hours after manufacturing decreased the IC50 concentration significantly by 66%. The LC-MS/MS method was found to be sensitive, selective and accurate for the determination of artesunate and its active metabolite, dihydroartemisinin (DHA) in mouse plasma and mefloquine in mouse whole blood. Most of the artesunate plasma concentrations were below the limit of quantification in the reference group and relatively high outliers were observed in some of the samples. The mean artesunate levels of the Pheroid™ vesicle group were lower compared to the reference group, but the variation within the Pheroid™ vesicle group lessened significantly. The mean DHA concentrations of the Pheroid™ vesicle group were significantly higher. DHA obtained a higher peak plasma drug concentration with the Pheroid™ vesicle group (173.0 ng/ml) in relation to the reference group (105.0 ng/ml) and at a much faster time (10 minutes in Pheroid™ vesicles in contrast to 30 minutes of the reference group). Pharmacokinetic models could not be constructed due to blood sampling per animal limitation. The incorporation of mefloquine in Pheroid™ vesicles did not seem to have improved results in relation to the reference group. No statistical significant differences were observed in the pharmacokinetic parameters between the two groups. The relative bioavailability (%) of the Pheroid™ vesicle incorporated mefloquine was 7% less bioavailable than the reference group. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

A static in vitro digestion method was developed as a strategy to understand the effects of modelled digestion on the solubility of nutrients and selected bioactive compounds of autoclaved and untreated wheat bran. Brans from common soft, hard, and durum wheats were evaluated. Results indicated that the in vitro digestion protocol was suitable and effective. Effects of gastrointestinal simulation were considerably larger than gastric digestion alone. Digestibility of the brans ranged from 28.1 to 47.9%. Digestibility of bran minerals, starch and protein was substantial compared to lesser, but still significant, effects on fibre. Fibre solubility was significantly enhanced due to autoclaving. Total phenolic content, free radical scavenging and metal chelation activity were all substantially increased in soluble digests. Yields of these factors indicated that digestion of wheat bran releases ample levels of antioxidants that would be available for absorption in the small intestine to promote beneficial health effects.

Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

Malaria is currently one of the most imperative parasitic diseases in developing countries. Artesunate has a short half-life, low aqueous solubility and resultant poor and erratic absorption upon oral administration, which translate to low bioavailability. Mefloquine is eliminated slowly with a terminal elimination half-life of approximately 20 days and has neuropsychiatric side effects. Novel drug delivery systems have been utilised to optimise chemotherapy with currently available antimalarial drugs. Pheroid™ technology is a patented drug delivery system which has the ability to capture, transport and deliver pharmaceutical compounds. Pheroid™ technology may play a key role in ensuring effective delivery and enhanced bioavailability of novel antimalarial drugs. The aim of this study was to evaluate the possible efficacy and bioavailability enhancement of the selected antimalarial drugs, artesunate and mefloquine, in combination with Pheroid™ vesicles. The in vitro efficacy of artesunate and mefloquine co-formulated in the oil phase of Pheroid™ vesicles and entrapped in Pheroid™ vesicles 24 hours after manufacturing were investigated against a 3D7 chloroquine-sensitive strain of Plasmodium falciparum. Parasitemia (%) was quantified with flow cytometry after incubation periods of 48 and 72 hours. Drug sensitivity was expressed as 50% inhibitory concentration (IC50) values. An in vivo bioavailability study with artesunate and mefloquine was also conducted in combination with Pheroid™ vesicles, using a mouse model. A sensitive and selective liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to analyse the drug levels. C57 BL6 mice were used during this study. The selected antimalarial drugs were administered at a dose of 20 mg/kg with an oral gavage tube. Blood samples were collected by means of tail bleeding. The in vitro drug sensitivity assays revealed that artesunate, co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period, decreased the IC50 concentration significantly by 90%. Extending the incubation period to 72 hours decreased the IC50 concentration of artesunate, also co-formulated in the oil phase of Pheroid ™ vesicles significantly by 72%. No statistically significant differences between the reference and Pheroid™ vesicle groups were achieved when artesunate was entrapped 24 hours after manufacturing of Pheroid™ vesicles. Mefloquine co-formulated in the oil phase of Pheroid™ vesicles and evaluated after a 48 hour incubation period decreased the IC50 concentration by 36%. Extending the incubation period to 72 hours increased the efficacy of the Pheroid™ vesicles and the IC50 concentration was significantly decreased by 51%. In contrast with the results obtained with artesunate, entrapment of mefloquine in Pheroid™ vesicles 24 hours after manufacturing decreased the IC50 concentration significantly by 66%. The LC-MS/MS method was found to be sensitive, selective and accurate for the determination of artesunate and its active metabolite, dihydroartemisinin (DHA) in mouse plasma and mefloquine in mouse whole blood. Most of the artesunate plasma concentrations were below the limit of quantification in the reference group and relatively high outliers were observed in some of the samples. The mean artesunate levels of the Pheroid™ vesicle group were lower compared to the reference group, but the variation within the Pheroid™ vesicle group lessened significantly. The mean DHA concentrations of the Pheroid™ vesicle group were significantly higher. DHA obtained a higher peak plasma drug concentration with the Pheroid™ vesicle group (173.0 ng/ml) in relation to the reference group (105.0 ng/ml) and at a much faster time (10 minutes in Pheroid™ vesicles in contrast to 30 minutes of the reference group). Pharmacokinetic models could not be constructed due to blood sampling per animal limitation. The incorporation of mefloquine in Pheroid™ vesicles did not seem to have improved results in relation to the reference group. No statistical significant differences were observed in the pharmacokinetic parameters between the two groups. The relative bioavailability (%) of the Pheroid™ vesicle incorporated mefloquine was 7% less bioavailable than the reference group. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2010.

A seven-step sequential extraction scheme was used to track changes in operationally defined copper speciation during the composting of a mixture of grass clippings and sawdust originating from tanalised timber. Starting materials were either unamended or treated with differing amounts of soluble copper, using a copper acetate solution, and then composted in the laboratory. Results showed that at the start of the experiment over 80% of the copper present in the unamended materials occurred in forms not immediately available for plant uptake. However, composting processes enabled the release of this copper which then, over time, became more bioavailable. Large amounts of copper in the copper amended materials were initially detectable in all fractions except the residual one, but over time it was seen to move from all fractions to the EDTA extractable fraction, thought to determine organically complexed / chelatable metals (Amir, 2005). This continued until an equilibrium was reached and then the water and calcium nitrate extractable forms appeared to hold the excess. Copper as determined by these extracts would be available for plant uptake. In the second experiment, three different organic wastes (grass/sawdust, pig slurry/sawdust and sewage sludge cake/sawdust) to which copper had been added as copper acetate, sulphate or EDTA, were composted in the laboratory. Samples were taken at 0, 105 and 318 days and subjected to a range of analyses: copper by sequential extraction using two different extraction schemes, a chelating resin membrane (CRM) procedure and by XRF spectrometry; FTIR analysis for functional groups; total carbon, nitrogen and sulphur; pH, EC, NH4+ and NO3- nitrogen, COD, germination indices and optical properties of water extracts. Sequential extractions demonstrated clear changes in copper distribution amongst various fractions within the materials, with copper originally present in the materials being transferred from the oxidisable fractions to easily extractable (and hence potentially phytoavailable) fractions. Transfer of copper from available to less available fractions in copper amended materials was also seen with movement of copper within copper EDTA treated materials being the slowest of all. Initial amounts of copper in fraction 1 extracted from all samples determined the rate at which copper was transformed. CRM determined copper correlated strongly with copper from fraction 1 of the Tessier scheme, although changes over time did not correspond well. Other parameters measured indicated that that the material was maturing (decreases in C/N and polysaccharide functional groups). However, other results demonstrated that the composts were still immature and unstable. Such slow decomposition was attributed to the high lignin content of the materials. Nevertheless, immobilisation of potentially phytotoxic level of copper was still demonstrated. The usefulness of chelating resin membrane as a predictor of phytoavailable copper is also discussed.

Toxic antifouling agents such as tributyltin (TBT) and triphenyltin (TPT) have been released in aquatic ecosystems through the use of antifouling paint applied to ship hulls, pleasure crafts and fish nets. The purpose of this study was to assess the use of zebra mussels (Dreissena polymorpha ) as a biomonitor for investigating the geographical variations of organotin bioavailability along the St. Lawrence River. Organotins TBT and TPT and their degradation products were first measured in the soft tissues of zebra mussels collected from along the River. High concentrations of TBT were found in mussels from Bassin Louise, a marina in Quebec City (1442 ng/g wet weight). TPT concentrations were elevated at 2 sites near Quebec City (252 and 530 ng/g wet weight). A follow-up study assessed the extent of the distribution of organotins from the contaminated marina to the River system by measuring organotin concentrations in zebra mussels and in sediments collected River near Quebec City. The highest concentration of TBT was found in Bassin Louise (1078 ng/g wet weight) and elevated concentrations were found in two other marinas. The concentrations decreased sharply to background levels just outside the marinas. All butyltins were detected in all sediments analysed. There was a significant correlation between TBT in sediments and mussels. These studies suggest that organotin contamination may remain a problem in localized freshwaters in the St. Lawrence River.

Triple fortification of salt with vitamin A, iron, and iodine has been investigated in the past to reduce micronutrient deficiencies in the developing world. The objective is to develop integrated nutrient delivery technology by microencapsulating a self-emulsifying drug delivery system (SEDDS) made of surfactants and a bioactive compound, retinyl palmitate. The SEDDS is used to enhance absorption of the vitamin A through food systems and to achieve targeted release of the active ingredient. Encapsulating vitamin A was difficult when using the spray dryer and the enteric coating, Aquacoat®. Losses of the micronutrient after a three month storage period ranged from 50-99% at both 25°C/20% RH and 45°C/60% RH. The result of a matrix encapsulation and poor coating formation contributed to the high losses. Further investigation of coating systems with the aim of stabilizing all three samples for a six month storage period such as using other encapsulating methods is recommended.

Triple fortification of salt with vitamin A, iron, and iodine has been investigated in the past to reduce micronutrient deficiencies in the developing world. The objective is to develop integrated nutrient delivery technology by microencapsulating a self-emulsifying drug delivery system (SEDDS) made of surfactants and a bioactive compound, retinyl palmitate. The SEDDS is used to enhance absorption of the vitamin A through food systems and to achieve targeted release of the active ingredient. Encapsulating vitamin A was difficult when using the spray dryer and the enteric coating, Aquacoat®. Losses of the micronutrient after a three month storage period ranged from 50-99% at both 25°C/20% RH and 45°C/60% RH. The result of a matrix encapsulation and poor coating formation contributed to the high losses. Further investigation of coating systems with the aim of stabilizing all three samples for a six month storage period such as using other encapsulating methods is recommended.

Several biologically important arsenic compounds including methylarsonate, trimethylarsine oxide, tetramethylarsonium ion, arsenobetaine and arsenocholine were prepared, in good yields, from sodium arsenite, or dimethylarsinic acid. These organoarsenic compounds together with arsenite, arsenate and dimethylarsinic acid were used as standards for the development of analytical methods for determining the levels of individual arsenic compounds (arsenic speciation) present in natural matrices. / Arsenobetaine, arsenocholine and tetramethylarsonium ion were separated by high performance liquid chromatography (HPLC) with on-line detection by thermochemical hydride generation (THG)-AAS. The analytes were eluted from the cyanopropyl bonded phase HPLC column with a 1% acetic acid methanolic mobile phase which also contained diethyl ether triethylamine, and trimethylsulfonium iodide or picrylsulfonic acid. A surface response methodology and a univariate optimization procedure were used to determine the optimum concentration of solvent modifiers in the methanolic mobile phase. Limits of detection in the range 4-5 ng (as As) were obtained for the arsonium analytes under optimum chromatographic conditions. / A simple phenol extraction procedure was developed to isolate arsonium analytes from edible marine tissues (lobster tail muscle, peeled and deveined shrimp, and cod fillet), cod liver oil and human urine. The crude extracts were separated on the cyanopropyl column using a methanolic mobile phase and detected on-line by THG-AAS. Recoveries from tissues or from urine which had been spiked at 0.1-3.4 $ mu$g of As cation/g of fresh weight were 80% or greater for each of five sample types. / An improved HPLC-AAS interface which was compatible with either aqueous or organic mobile phases was also developed. The interface provided approximately equivalent responses to different arsenic oxidation states which resulted in low to subnanogram chromatographic limits of detection for arsenic oxyanions and arsonium cations in an aqueous or methanolic mobile phase. Nascent As anions and As cations were conveniently coextracted from aqueous solution or from fish muscle by phenol extraction and quantified in the same chromatographic run. This method has been applied to a standard reference sample of dogfish muscle (DORM-1), a marine reference sediment sample (PACS-1) and to sediment porewaters (SAG-15) from the Saguenay Fjord.

The antioxidant capacity of phenolic compounds in red wine is suggested to be responsible for their health-promoting effects. Compared to other wines, little information is available on phenolic compositions and antioxidant capacity of Australian wine. Information related to the fate of these phenolics in the body once consumed is also very limited. The overall aim of this research was to investigate the relevance of red wine consumption as a source of health-giving antioxidants in humans. The phenolic composition of wine was determined using the Folin-Ciocalteu (total phenolic), aluminium chloride (total flavonols), methyl cellulose precipitation (MCP) (total tannins), pH differential (total monomeric anthocyanins), bisulfite bleaching (total polymeric anthocyanin fractions), and liquid chromatographic (LC-MS) (individual phenolics) methods. Antioxidant activities were measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis-93-ethylbenzthiazoline-6-sulfonic acid (ABTS) and oxygen radical absorbance capacity (ORAC) assays. The phenolic and antioxidant data were then used to establish the relationship between these two parameters in wines from different varieties (Shiraz, Cabernet Sauvignon and Merlot) and winemaking stages (crushing, fermentations, oaking and bottling). By using an in vitro digestion model that mimics the upper gastrointestinal tract (GIT) digestion, the stability of the wine phenolics during digestion was examined. Finally, to gain a better understanding of the post-digestion absorption of wine phenolics, their permeability across Caco-2 cell monolayers was evaluated. A total of 8 monomeric anthocyanins and 17 other phenolic compounds were positively identified in the red wines using LC-MS analysis. Most of the phenolic categories showed some positive correlations with the antioxidant activities but none of the individual phenolic compounds showed a strong correlation with the total antioxidant activity of the wine, implying a combined contribution of many wine phenolics to antioxidant effects. The phenolic compositions and antioxidant activities of three of Australia’s most common red wines varieties - Shiraz, Cabernet Sauvignon and Merlot were not different from each other, possibly due to the variability within each grape cultivar. During the winemaking process, the total phenolic content and the associated antioxidant activity of the wine increased during the fermentation process, as more phenolics are being extracted from grape skin, seeds and stems into the wine. During oak and bottle ageing, the total phenolic contents were stabilised. Most of the wine phenolics were more stable under acidic conditions (pH 2 and 5.5) than neutral or alkaline conditions (pH 7.4 and 9). This may partly explain the stability of the wine phenolics subjected to the acidic (pH 2) gastric digestion and their loss following simulated pancreatic digestion (pH 7.4). In addition, sample pre-treatment procedures prior to LC-MS analysis may have removed some antioxidants in the form of degradation products and/or new polymeric compounds following the in vitro gastric and pancreatic digestion processes. The missing products appeared to be detected by both the Folin-Ciocalteu method and ORAC assay, which measured the phenolic compounds and their antioxidant activity, after the pancreatic digestion. This suggests that the instability of phenolic compounds at pH 7.4, results in the transformation of most of the oral phenolic antioxidants into more stable forms in the GIT, which in turn contribute positively to the overall antioxidant activities of the ingested wine. All of the original wine phenolics had very low permeabilities across Caco-2 cell monolayers, except for syringic acid, p-coumaric acid and an unknown phenolic acid. Limited surface area for absorption (0.33 cm2) and the limited peak detection sensitivity in the LC method may have contributed towards the difficulty in detecting and identifying compounds with low permeability. In addition, extensive metabolism of absorbed phenolics by the Caco-2 cells may occur based on the appearance of several new peaks. However, due to their low concentrations and lack of reference, the identities of the new products and metabolites remain unknown. The present in vitro study suggests that upon ingestion, most of the original phenolic compounds in red wine are lost either through degradation to new compounds and/or complexation with other compounds. However, these products seem to possess some antioxidant activity and may be the key compounds responsible for the health-promoting effects of red wine. The limitation of the present study in detecting and fully identifying these breakdown products and metabolites should be addressed in future studies.