Atopic dermatitis (AD) is a non-contagious chronic inflammatory skin disease with the lifetime prevalence estimated to be 10–30 % in children and 2–10 % in adults. Atopic skin is characterised as dry and sensitive, accompanied by itch. Skin barrier dysfunction, distinctive in AD, occur under the influence of a mix of genetic, environmental and inflammatory factors. Daily skin care routine and the avoidance of allergens and the inflammation triggers that can worsen the condition have important role in the management of AD, while in the treatment, initially local anti-inflammatory therapy, and in severe AD, also systemic therapy is used.
In addition to conventional dermal pharmaceutical forms, the use of hydrogels is also being investigated for the treatment of AD. Hydrogels are defined as three dimensional polymeric networks of gelling agents with the ability of swelling and holding a large quantity of water within its scaffold. Within the master's thesis hydrogels based on nanocrystalline cellulose (NCC) from two different manufacturers, differing also in macroscopic characteristics (i.e. gel or powder NCC), were developed and evaluated. Beside NCC, hydrogels also consisted of one of three different natural polymers (alginate, pectin or low viscosity chitosan), glycerol, and betamethasone dipropionate (BDP) as model active pharmaceutical intgredient (API) otherwise used to treat AD. We first focused on optimizing the incorporation of BDP in the form of a self-microemulsifying system (SMES) into hydrogels. The differential scanning calorimetry (DSC) method confirmed that the API incorporated in the hydrogels was dissolved. The influence of two different NCC and SMES on the viscosity and amplitude and frequency dependence of the elastic and plastic modulus was evaluated by rheological measurements. The powderish NCC was found to form more viscous hydrogels while the addition of SMES (with or without incorporated BDP) either increased or decreased the viscosity or the values of one or both modules, depending on the natural polymer and NCC used. Furthermore, films were prepared from hydrogels containing SMES (with and without BDP) using the solvent evaporation method. The prepared films showed a low residual moisture content (up to 2,15 % m/m) and a maximum thickness of 0,090 ± 0,007 mm. In addition, the prepared films showed a statistically significant difference in water retention ability after application to a cellulose acetate membrane. The hydrogels produced have proven to be potential delivery systems for BDP in the treatment of AD.
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