Borneol and lactoferrin dual-modified crocetin-loaded nanoliposomes enhance neuroprotection in HT22 cells and brain targeting in mice.

Crocetin (CCT), a natural bioactive compound extracted and purified from the traditional Chinese medicinal herb saffron, has been shown to play a role in neurodegenerative diseases, particularly depression. However, due to challenges with solubility, targeting, and bioavailability, formulation development and clinical use of CCT are severely limited. In this study, we used the emulsification-reverse volatilization method to prepare CCT-loaded nanoliposomes (CN). We further developed a borneol (Bor) and lactoferrin (Lf) dual-modified CCT-loaded nanoliposome (BLCN) for brain-targeted delivery of CCT. The results of transmission electron microscope (TEM) and particle size analysis indicated that the size of BLCN (∼140 nm) was suitable for transcellular transport across olfactory axons (∼200 nm), potentially paving a direct path to the brain. Studies on lipid solubility, micropolarity, and hydrophobicity showed that BLCN had a relatively high Lf grafting rate (81.11 ± 1.33 %) and CCT entrapment efficiency (83.60 ± 1.04 %) compared to other liposomes, likely due to Bor improving the lipid solubility of Lf, and the combination promoting the orderly arrangement of liposome membrane molecules. Microplate reader and fluorescence microscopy analysis showed that BLCN efficiently promoted the endocytosis of fluorescent coumarin 6 into HT22 cells with a maximal fluorescence intensity of (13.48 ± 0.80 %), which was significantly higher than that of CCT (5.73 ± 1.17 %) and CN (12.13 ± 1.01 %). BLCN also exhibited sustained function, remaining effective for more than 12 h after reaching a peak at 1 h in cells, while CN showed a significant decrease after 4 h. The uptake mechanisms of BLCN in HT22 cells mainly involve energy-dependent, caveolae-mediated, and microtubule-mediated endocytosis, as well as micropinocytosis. Furthermore, BLCN displayed a significant neuroprotective effect on HT22 cells in glutamate-, corticosterone-, and H2O2-induced models. Tissue fluorescence image analysis of mice showed that BLCN exhibited substantial retention of fluorescent DiR in the brain after nasal administration for 12 h. These findings suggest that CCT has the potential for cellular uptake, neuroprotection, and targeted delivery to the brain following intranasal administration when encapsulated in Bor and Lf dual-modified nanoliposomes.

Enhancement of dissolution and oral bioavailability by adjusting microenvironment pH in crocetin ternary solid dispersions: Optimization, characterization, in vitro evaluation, and pharmacokinetics.

The most promising active ingredient of Crocus sativus L., crocetin (CCT), has been demonstrated to possess many biological activities. However, only a few studies have been conducted on CCT formulation, especially in oral formulation, mainly due to its insolubility in water, which limits its application for oral administration. This article reports an equilibrium saturation solubility and single-pass intestinal perfusion studies conducted to classify the biopharmaceutics classification system (BCS) of CCT. To enhance in vitro dissolution and in vivo oral bioavailability, ternary solid dispersions of CCT (CCT-SDs) with soluplus (SOL) as hydrophilic carrier and meglumine (MEG) as alkalizer were optimized using response surface methodology (RSM) with central composite design (CCD) experiments. Four different preparation methods were evaluated using the optimal formulation, including solvent evaporation, ball milling, spray drying, and freeze-drying. Prepared formulations were characterized by TG-DSC, FTIR, X-RPD, and SEM; the pharmacokinetic studies were performed in rats after oral administration. The cumulative dissolution rate of CCT-SDs containing SOL and MEG prepared by the ball milling method was 97.1% at 15 min and remained at 95.6% at 480 min, which was significantly higher than that of untreated CCT. The lower crystallinity, smaller particle size, and higher microenvironment pH (pHM) were observed in CCT-SDs prepared by the ball milling method. In vivo absorption of CCT-SDs (Cmax = 52.789 ± 12.441 µg/mL and AUC0-12 = 191.748 ± 35.043 µg/mL·h) was greater than untreated CCT (Cmax = 5.918 ± 1.388 µg/mL and AUC0-12 = 44.309 ± 7.264 µg/mL·h). In conclusion, the current study provides ternary solid dispersion formulation of CCT to increase the in vitro dissolution and in vivo bioavailability, which will benefit the commercial production and future clinical applications of CCT.