In Vivo Tissue Distribution and Pharmacokinetics of FITC-Labelled Hizikia fusiforme Polyphenol–Polysaccharide Complex in Mice

In this study, a quantitative method based on fluorescein isothiocyanate (FITC)-labelled <i>Hizikia fusiforme</i> polyphenol-polysaccharide complex (HPC) and its purified fractions (PC1, PC4) was used, and its pharmacokinetics and tissue distribution were investigated in mice. The results showed that the FITC-labelled method had good linearity (R² > 0.99), intra-day and inter-day precision (RSD, %) consistently lower than 15%, recovery (93.19-106.54%), and stability (RSD < 15%), which met the basic criteria for pharmacokinetic studies. The pharmacokinetic and tissue distribution results in mice after administration showed that all three sample groups could enter the blood circulation. and HPC-FITC had a longer half-life (T_1/2: 26.92 ± 0.76 h) and mean retention time (MRT_0-∞: 36.48 h) due to its larger molecular weight. The three groups of samples could be absorbed by the organism in a short time (0.5 h) mainly in the stomach and intestine; the samples could be detected in the urine after 2 h of administration indicating strong renal uptake, and faecal excretion reached its maximum at 12 h. The samples were also detected in the urine after 2 h of administration. This study provides some theoretical basis for the tissue distribution pattern of polyphenol-polysaccharide complex.