Synthesis and evaluation of hydrophobically modified fenugreek gum for potential hepatic drug delivery

Fluorescence probe technique for determining the hydrophobic interactions and critical aggregation concentrations of Gleditsia microphylla gum, circular Gleditsia sinensis gum, and tara gum

Circular Gleditsia sinensis gum, Gleditsia microphylla gum, and tara gum are galactomannans (GMs) with similar mannose/galactose (M/G) molar ratios, which complicates the characterization of physicochemical properties using conventional methods. Herein, the hydrophobic interactions and critical aggregation concentrations (CACs) of the GMs were compared using a fluorescence probe technique, in which the I1/I3 ratio of pyrene indicated polarity changes. With increasing GM concentration, the I1/I3 ratio decreased slightly in dilute solutions below the CAC but decreased sharply in semidilute solutions above the CAC, indicating that the GMs formed hydrophobic domains. However, increases in temperature destroyed the hydrophobic microdomains and increased the CACs. Higher concentrations of salts (SO42-, Cl-, SCN-, and Al3+) promoted hydrophobic microdomain formation, and the CACs in Na2SO4 and NaSCN solutions were lower than those in pure water. Hydrophobic microdomain formation also occurred upon Cu2+ complexation. Although urea addition promoted hydrophobic microdomain formation in dilute solutions, the microdomains were destroyed in semidilute solutions and the CACs increased. The formation or destruction of hydrophobic microdomains depended on the molecular weight, M/G ratio and galactose distribution of GMs. Therefore, the fluorescent probe technique enables the characterization of hydrophobic interactions in GM solutions, which can provide valuable insight into molecular chain conformations.

Natural Gums in Drug-Loaded Micro- and Nanogels

Gums are polysaccharide compounds obtained from natural sources, such as plants, algae and bacteria. Because of their excellent biocompatibility and biodegradability, as well as their ability to swell and their sensitivity to degradation by the colon microbiome, they are regarded as interesting potential drug carriers. In order to obtain properties differing from the original compounds, blends with other polymers and chemical modifications are usually applied. Gums and gum-derived compounds can be applied in the form of macroscopic hydrogels or can be formulated into particulate systems that can deliver the drugs via different administration routes. In this review, we present and summarize the most recent studies regarding micro- and nanoparticles obtained with the use of gums extensively investigated in pharmaceutical technology, their derivatives and blends with other polymers. This review focuses on the most important aspects of micro- and nanoparticulate systems formulation and their application as drug carriers, as well as the challenges related to these formulations.

Study on the structure and physicochemical properties of fenugreek galactomannan modified via octenyl succinic anhydride

To improve the mechanical strength of borax-crosslinked fenugreek galactomannan hydrogels and broaden the application field of galactomannan-based hydrogels, fenugreek galactomannan (FG) was esterified via octenyl succinic anhydride (OSA), and the parameters affecting the esterification reaction were systematically studied. The optimum process for OSA-modified FG (OFG) was as follows: FG concentration 1.5 wt%, n (OSA): n (FG) = 2, n (4-dimethylamino-pyridine, DMAP): n (FG) = 4, and reaction time 12 h. Under this condition, the degree of substitution (DS) was 0.31, and the product yield was 115.05 %. Characterization of FT-IR, H¹ NMR, and HPLC confirmed that the OSA group was successfully introduced into the FG skeleton. The mechanical strength of borax crosslinked OFG hydrogel (OFGH) is 18 times higher than that of FG hydrogel. OFGH shows excellent self-healing, injectable properties and electrical conductivity. This will further expand the application of borax crosslinked galactomannan-based hydrogels in the fields of sensors, drug delivery, and wound dressing.

Hepatic targeting of glycyrrhetinic acid via nanomicelles based on stearic acid-modified fenugreek gum

This study aimed to increase the solubility of glycyrrhetinic acid (GA) in water and enhance its liver-targeting ability using self-assembling nanomicelles (NMs) based on stearic acid-modified fenugreek gum (FG-C₁₈). The GA/FG-C₁₈ NMs were prepared by an ultrasonication dispersion method. The nanomicelles were spherical particles with a particle size of 198.61 ± 1.58 nm and a zeta potential of -30.12 ± 0.28 mV. The drug loading and encapsulation efficiency were 13.34 ± 0.24% and 80.07 ± 1.44%, respectively. The results of differential scanning calorimetry (DSC) and X-ray powder diffraction (XRD) indicated that GA was successfully encapsulated into the nanomicelles in a molecularly dispersed state. An in vitro release test showed that GA/FG-C₁₈ NMs possessed a slow drug release profile in PBS (pH 7.4) over 200 h. The cytotoxicity assay indicated that GA/FG-C₁₈ NMs showed much higher inhibitory efficacy in HepG2 cells than in MCF-7 cells. Tissue section studies indicated that the accumulation of DiR-loaded FG-C₁₈ nanomicelles in the liver of mice was higher than that of the DiR solution, and the fluorescence intensity decreased over time. GA/FG-C₁₈ NMs showed a larger area under the curve (AUC) and mean residence time (MRT) compared with free GA after intravenous administration in mice. The in vivo studies showed that GA mainly accumulated in the liver after encapsulation by FG-C₁₈ NMs, and the drug concentration was higher than that of free GA. These results suggested that FG-C₁₈ NMs could serve as a potential drug delivery system for targeting GA to liver tissue.