Solid lipid nanoparticles represent a newer delivery system that allows the incorporation of lipophilic and hydrophilic active ingredients, the use of biocompatible and biodegradable compounds, controlled and targeted release of active ingredients, and are easy to fabricate. Due to their advantages over conventional colloidal delivery systems, they have also been introduced in cosmetics. In particular, they are used for delivery of lipophilic cosmetically active ingredients, as these are more difficult for incorporation into conventional dermal formulations. One of these ingredients is cannabidiol, which has antioxidant, anti-inflammatory and antipruritic activity. Several studies have demonstrated its positive effects in different skin conditions, such as acne, allergic contact dermatitis and psoriasis.
The aim of this diploma thesis was to prepare stable solid lipid nanoparticles with incorporated cannabidiol. Firstly, empty solid lipid nanoparticles were prepared by varying the formulation composition and manufacturing conditions and the most optimal formulation was selected. After the optimisation of the formulation and the preparation process was completed, cannabidiol was incorporated into the nanoparticles. Solid lipid nanoparticles were prepared with 10 % (w/w) cannabidiol. The physical stability of the nanoparticle dispersions was monitored by photon correlation spectroscopy and laser Doppler anemometry during 21 days of storage at room temperature and at 4 °C. The average hydrodynamic diameter of the particles, the polydispersity index and the zeta potential of the particles were measured. It was observed that the particles in dispersion were relatively physically stable, with only a slight increase in average particle size at both storage conditions and almost unchanged polydispersity index. However, the zeta potential value was slightly more negative after 21 days in the case of storage at temperature 4 °C. The content of cannabidiol in the solid lipid nanoparticle dispersion was evaluated by high-performance liquid chromatography. The initial content was 46,83 mg/mL and a decrease in the content was observed already after 7 days. After 21 days, 76,9 % of the initial cannabidiol content was determined in the sample stored at room temperature and 86,5 % in the sample stored at 4 °C. On the basis of these results, it can be concluded that cannabidiol in the selected formulation of solid lipid nanoparticles was not chemically stable. However, we have shown that prepared dispersion of solid lipid nanoparticles with canabidiol is physicaly stable and that cannabidiol stability is better when stored in a fridge.
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