The influence of technological factors on changes of texture of gel systems with chitosan

Final master thesis of E. Keliauskaitė “The influence of technological factors on changes of texture of gel systems with chitosan“/ Scientific supervisor Prof. dr. Jurga Bernatonienė; Lithuanian University Of Health Sciences, Medical Academy, faculty of pharmacy, Department of Drug Technology and Social Pharmacy, Kaunas, 2018. Object of research – different molecular weight and concentration chitosan hydrogels, chitosan hydrogels with different concentrations of P. graveolens L. essential oil. The tasks of research: according to scientific literature invent CH recipes and prepare hydrogels with different molecular weight and concentration chitosan. To estimate different stirring speed and time setting influence to hydrogel texture. Asses how physical stability fluctuate at the room temperature conditions and performed accelerated stability test. Analyse chitosan hydrogel stability by performing pH value measurement, microscopic analysis and centrifugation test. Methods: The influence of technological factors on changes in the structure of chitosan hydrogel was evaluated through texture analysis. Chitosan hydrogel stability is evaluated by: physical stability assessment, determination of pH value, microscopic examination and centrifuge test. An accelerated stability study was also conducted, which lasted 3 months. Results: The texture analysis revealed that 1 proc. CH hydrogel textural parameters (firmness, consistency, cohesiveness and index of viscosity) were the lowest and 5 proc. CH hydrogel had the highest texture parameters. Depending on the molecular weight, it was found that texture parameters of the LMW CH hydrogel were significantly lowest and significant higher were HMW 80/3000 CH hydrogel. It was found that the CH hydrogel with 5 proc. glycerol exhibited significantly higher texture parameters than the control CH hydrogel. It has been found that significant changes in texture are observed when the stirring rate is 1500 rpm and the stirring time is 60 minutes. The analysis of the texture showed that the addition of P.Graveolens L. essential oil to the chitosan hydrogel showed significant changes in the hardness, consistency and adhesion properties, but the viscosity index does not change. Using a microscopic analysis method, the pH value test, centrifugation test showed that hydrogels are homogeneous, without impurities. Accelerated stability and physical stability test showed that hydrogels loses their stability over time. Conclusions: Based on the results of the research, it was determined that stirring speed had influence on firmness, cohesiveness and stirring time had influence on firmness, consistency, cohesiveness, index of viscosity. All prepared CH hydrogels loses their stability over time