The greatest advantage of eye gels compared to other ophthalmic drug dosage forms is the longer retention time at the application site due to their higher viscosity. The gel formers are different polymers or their combinations. Hydroxypropylmethylcellulose is a cellulose derivative which has reversible thermogel properties and its solubility in water decreases with increasing temperature. Polycarbophil is a polyacrylate polymer which forms acid dispersions and swells in water. It forms a hydrogel when the pH of the dispersion medium is increased. In this master thesis we evaluated the technological procedure for production of a hydrophilic eye gel based on a combination of hydroxypropylmethylcellulose and polycarbophil. Gel samples were produced by varying the technological parameters of the gel production and, in some cases, also the composition of the formulation. The rheological properties of all final gels were evaluated by performing a rotational test of viscosity measurement at constant rotation rate, a rotational test with logarithmic increase in shear rate and an oscillatory amplitude sweep. Behaviour of the formulations during the gel samples preparation itself was also monitored and evaluated visually. Good dispersion of the polymers in the dispersion medium proved to be an important step in the gel preparation process, as it is a prerequisite for adequate functionality of the polymers and to obtain a homogeneous gel with appropriate rheological properties. During gel preparation, the foaming tendency of the dispersion requires adjustments of the production process, to minimise foaming. As essential parameters affecting the rheological properties of the gel, we identified the polymer concentration, pH of the final gel and autoclaving of the polymer dispersion blend, mainly due to the temperature-dependent behaviour of the aqueous dispersion of hydroxypropylmethylcellulose. We found that polycarbophil is mainly responsible for the elastic behaviour of the viscoelastic gel, while hydroxypropylmethylcellulose has a notable influence only on the plastic properties of the gel. We also detected the temporal effect of gel ageing on the rheological properties of the gel. The influence of other technological parameters was noticeable but less pronounced. Since two polymers with different properties were present as thickeners in the formulation, the evaluation of the influence of the gel production process on the rheological properties of the gel was further complicated by the potential interactions of the polymers.
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