No description available.

Graduation date: 1998

Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Food Science." Includes bibliographical references (p. 122-130).

No description available.

No description available.

Thesis (M.E.)--University of Waikato, 2008. / Title from PDF cover (viewed September 18, 2008) Includes bibliographical references (p. 66-70)

Thesis (Master)--İzmir Institute of Technology, İzmir, 2004. / Includes bibliographical references (leaves. 55-58).

In this study, lanolin alcohol as well as lanolin alcohol-povidone films (1:1 . 5) were investigated as a potential drug delivery system. The in vitro drug release from these films was studied in terms of the effect of agitation, film thickness and drug concentration. The rate of release of Cortisol from lanolin alcohol films was not affected by the intensity of agitation. Moreover, the film matrix was found to remain essentially intact throughout the release process. Further analysis of the data revealed that Higuchi's diffusion-controlled granular matrix model explained the mechanism of Cortisol release from such films. The results of drug release from lanolin alcohol povidone films have shown that although Higuchi's release rate constant was found to be independent of film thickness, it was affected by the intensity of agitation, since the rate constant was found to increase as agitation speed was increased, especially at low speeds. In addition, povidone was found to leach out of the film matrix along with the drug. These factors, in conjunction with further analysis of the drug, explained the failure of this film system to conform to the matrix-controlled diffusion model. The release rate of Cortisol from this film system was found to follow first-order dependence on drug concentration. The drug was found to be completely insoluble in lanolin alcohol, and slightly soluble in povidone. Povidone was found to enhance the solubility of Cortisol in water.

Thesis (M.Sc.(Tech.))--University of Waikato, 2006. / Includes bibliographical references (leaves 221-230) Also available via the World Wide Web.

The topical application of many substances, including drugs, enzymes, moisturizers and fragrances, contributes largely to the cosmetic and pharmaceutical industries. These components are often volatile in nature and dissipate in a matter of hours. When considering the different types of slow release systems, an overwhelming variety of these systems is available. Each one of the systems is unique in a way, and is designed to perform a particular function, whether it facilitates the controlled release of an active into the body via the skin surface (transdermal delivery) or whether it reduces the rate of loss of an active from the skin surface to the surrounding environment. For the purpose of this study, a previously existing fixative formulation which is believed to reduce the rate of loss of an active component to the environment, through film formation on the skin surface, was investigated. Alternative ingredients or components were incorporated together with the original fixative formulation ingredients into an experimental design which investigates the effect of each group of the components present. 18 formulations with various concentrations of the components within the groups and specified upper and lower limits for each component were formulated. The fixative properties of the formulations were analysed through the incorporation of a fixed amount of a simple fragrance molecule, 4- methoxybenzaldehyde, into each formulation and evaporation studies were conducted in an environmental room at 28±1° C over a period of 5 hours followed by gas chromatography analysis and finally data analyses using statistical methods. The most efficient fixative formulation was established using regression analysis. The fragrance compound in this formulation was found to evaporate at a rate of 0.47 g/L per hour. The least efficient fixative formulation lead to the loss of 0.78 g/L of the fragrance component per hour. From the calculated fragrance concentrations, the rate constant for each individual fixative formulation could be calculated and response surface 8 modelling by backward regression was used in order to determine how each component contributes to the rate of loss of the fragrance compound. Since the sum of the original ingredient and its alternative was constant, each of the original ingredients was coupled directly to its alternative and no conclusion could be made about the contribution of individual components. By increasing the concentration of Hydroxypropylcellulose (HPC) 100K and its alternative HPC 140K, while keeping the effects of the other components constant, a decrease in the rate of fragrance loss was observed. The same conclusion could be made when increasing the concentrations of PEG-12 Dimethicone and its alternative cetyl dimethicone (decreases the evaporation rate). An interaction took place between HPC 100K and PEG-12 dimethicone and their alternatives. The negative effect was, however, not as strong as the combined positive effect on the rate of fragrance loss of the individual components HPC and PEG-12 dimethicone. Evidence suggested that the removal of the components polyvinylpyrrolidone and its alternative, polyurethane-32 (Baycusan® C1003), would improve the effectiveness of the fixative formulation in terms of its slow release properties. A confirmation experiment established that the exclusion of these components from the fixative formulation does improve the “slow release” properties thereof. A larger, more intricate design is required to investigate the effect of each one of the individual components and where the sum of the components (original and its alternative) is not constant.