Inulin–Calendula officinalis Dermatocosmetic Hydrogels: Development, Physicochemical Characterization and Texture Profile Analysis

This study investigated dermatocosmetic hydrogel formulations containing inulin and a quality-controlled organic Calendula officinalis L. flower extract in 20% propylene glycol, with emphasis on physicochemical and textural characterization. Seven formulations were prepared and evaluated for organoleptic characteristics, pH, firmness, cohesiveness, springiness, and resilience. All formulations were macroscopically homogeneous, while pH values ranged from 6.28 ± 0.01 to 6.66 ± 0.04. Texture Profile Analysis revealed formulation-dependent mechanical behaviour. Firmness ranged from 0.430 ± 0.002 to 0.698 ± 0.042 N, cohesiveness from 0.660 ± 0.009 to 0.874 ± 0.013, springiness from 0.778 ± 0.001 to 0.941 ± 0.037, and resilience from 0.277 ± 0.005 to 0.494 ± 0.016. One-way ANOVA indicated an overall formulation effect for all four texture parameters (p < 0.0001), followed by Tukey HSD pairwise comparisons. Gel 2, containing 2% inulin without Calendula officinalis extract, exhibited the highest numerical firmness and springiness, whereas Gel 5, containing 4% inulin and 3% Calendula officinalis extract, showed the highest cohesiveness and resilience. The extract-only Gel 6 displayed the lowest numerical values for all four texture parameters. The results support a formulation-dependent, non-linear effect of inulin on gel mechanical behaviour and provide a physicochemical basis for subsequent rheological, stability, phytochemical, release, safety, and biological investigations.