| Přispěvatelé: |
Du Plessis, J., Gerber, M., Liebenberg, W., 10065318 - Du Plessis, Jeanetta (Supervisor), 11329025 - Gerber, Minja (Supervisor), 10196226 - Liebenberg, Wilna (Supervisor) |
| Popis: |
MSc (Pharmaceutics), North-West University, Potchefstroom Campus Wound healing can be described as a cascade of cells activated to restore tissue integrity, in order to regain the body’s natural function. Wound care plays a pivotal role in achieving therapeutic outcomes in wounds to counter various factors that can compromise the healing. It is proposed that by utilising aluminosilicates, with therapeutic agents incorporated in its structure, wound healing outcomes might be enhanced. One such entity which has been recognised for its wound healing characteristics, is Absorbatox®; a potentiated clinoptilolite belonging to the zeolite family. In this study, Absorbatox® was synthetically modified to incorporate metal cations in its structure. The selected cations included silver and zinc cations, taking form as new Absorbatox® entities. It was hypothesised that the cations would provide additive effects to enhance wound healing. The Absorbatox® entities were subjected to analysis and characterisation studies to provide supplementary information. Characterisation studies included x-ray fluorescence (XRF), and thermal analysis testing (DSC). X-ray powder diffractometry (XRPD), as well as Fourier-Transform Infrared spectroscopy (FTIR) was used to show the chemical compositions of the entities, whereas scanning electron microscopy (SEM) was conducted to show the surface morphologies. Thereafter, the in vitro efficacy studies were performed on two skin-derived cell lines seeded as monolayer cultures, namely pre-malignant human immortalised keratinocytes (HaCaT) and normal human dermal fibroblasts (84BR). The amount of silver and zinc ions incorporated into the Absorbatox® structure were expressed as a percentage of the particular cation per Absorbatox® molecule. The Absorbatox® entities (with either silver or zinc) were administered to the cells in two respective concentrations, i.e. 300 μg/ml and 150 μg/ml to provide different experimental groups. To evaluate the cytotoxicity, the in vitro cell viability was measured by using the methyl thiazolyl tetrazolium (MTT) assay. It was concluded that Absorbatox® with the selected cations improved the viability of both cell lines and no cytotoxic effects were observed for the Absorbatox® entities. The wound healing scratch assay was used to investigate the capability of the treated cells to close an induced wound. The Absorbatox® experimental groups showed a tendency to enhance the ability of both cell lines to close the wound field; Absorbatox® with silver cations incorporated into the structure caused a considerably higher cell migration percentage than Absorbatox® alone. These findings, together with the reports of other studies, substantiate the in vitro efficacy of a zeolite derivative, namely Absorbatox®, with silver or zinc incorporated in its structure, to provide a promising role in wound healing. Lastly, wound dressing materials including a silicone gel, as well as a dry dressing comprising the Absorbatox® entities were formulated and designed. The wound dressing materials were subjected to different accelerated storage conditions to determine whether a sense of stability was maintained over a period of three months. Upon investigation, the silicone gel comprising Absorbatox®-zinc was evaluated as stable, according to the guidelines of the International Conference on Harmonisation (ICH). However, chemical instabilities of the Absorbatox®-silver dry dressing were found, relating to unsatisfactory packaging and improved storage operation would deem better results with regard to chemical stability. Masters |
