Poznan University Technology

The aim of this study was to optimize a mucoadhesion testing protocol utilizing a vertical motorized test stand combined with a digital force gauge. The optimized protocol was applied to evaluate the mucoadhesive performance of various test materials, including lyophilized polymer matrices composed of chitosan, pectin, poly(vinyl alcohol) (PVA), and hydroxypropyl methylcellulose (HPMC); compressed pectin-only disks; and commercial enteric-coated (HPMC-based) capsules.

Optimization involved systematic evaluation of key test parameters including start speed, applied contact force, contact time, and return (detachment) speed. Standardized simulated gastric (SGF, pH 2) and intestinal fluids (SIF, pH 6.8) containing 1 % w/v mucin were employed as test media. Final measurements were expressed as detachment force normalized to the contact area (N/cm²) and corrected for baseline adhesion in mucin-free media.

Optimized conditions (start speed 10 mm/min, force 1 N, contact time 60 s, return speed 60 mm/min) allowed sensitive detection of material differences. Pressed pectin discs showed the highest mucoadhesive strength (>20 N/cm²).

The developed method is reliable for evaluating mucoadhesion using mucin-containing media. Polymer composition, environmental pH, and lyophilization strongly influenced adhesive performance. The protocol offers a standardized tool for the design of mucoadhesive drug delivery systems.

As a potential remedy for COVID-19 treatment, hydroxychloroquine (HCQ) attracted considerable scholarly attention early in the pandemic. However, the ecological consequences of HCQ are not well understood, especially regarding their interactions with plastic waste such as nano-and microplastics (PS). This study aimed to investigate colloidal stability, bioaccumulation, and acute toxicity of carboxylate-modified polystyrene-based PS and HCQ, both alone and in combination, to Salmo trutta embryos and larvae. Spectroscopic properties of PS were found to change over time and to be affected by the presence of HCQ in the incubation water of organisms. Confocal microscopy showed that PS and HCQ, both alone and in combination, caused damage to the chorion of the exposed fish embryos. Particles of PS were detected in external tissues of larvae. The impact of the tested substances on fish was found to be dependent on the PS particle size, exposure duration, and the life stage of fish.

Catechins, due to their high antioxidant capacity, are ones of the most common ingredients of human diet (e.g. tea, fruits, cacao) of the well-known health benefit properties. Catechins are relatively unstable compounds, therefore the degradation processes of catechins is of interest with respect to the human diet. Huang et al. (2025) have published an interesting paper devoted to the degradation process of (-)-epicatechin in boiling water and it is clear that the results may be of interest with respect to the food preparation processes. However, the issue which is disputable in the paper is the mass spectrometric identification of the 22 degradation products. Some of the claimed products are the well-known compounds, however, the reported fragmentation patterns are not in agreement with those documented in the scientific literature. If the claimed degradation product is the compound which is commercially available, its identification should be confirmed by analysis of the respective standard. Furthermore, in order to confirm the elemental composition of the claimed degradation products, the HPLC-MS analysis should be performed by using mass spectrometer equipped with high resolution analyzer.