Evaluation of chitosan/xanthan gum polyelectrolyte complexes potential for pH-dependent oral delivery of escin

Biofilm hydrogel derived from physical crosslinking (self-assembly) of xanthan gum and chitosan for removing Cd2+, Ni2+, and Cu2+ from aqueous solution

This study aimed to fabricate a series of biodegradable hydrogel films by gelating/physically crosslinking a blend of xanthan gum (XG) and chitosan (CS) in various combinations using a facile, green, and low cost solution casting technique. The adsorption of Cd2+, Cu2+ and Ni2+ by the XG/CS biofilm in aqueous solution was studied in batch experiments to determine how the pH of the solution, contact time, dosage of adsorbent, initial metal ion concentration and ionic strength affect its adsorption. A highly pH-dependent adsorption process was observed for three metal ions. A maximum amount of Cd2+, Ni2+, and Cu2+ ions was adsorbable with 50 mg of the adsorbent at pH 6.0 for an initial metal concentration of 50 mg.L-1. An empirical pseudo-second-order model seems to fit the kinetic experimental data reasonably well. It was found that the Langmuir model correlated better with equilibrium isotherm when compared with the Freundlich model. For Cd2+, Ni2+, and Cu2+ ions at 25 °C, the maximum monolayer adsorption capacity was 152.33, 144.79, and 139.71 mg.g-1, respectively. Furthermore, the biofilm was capable of regenerating, allowing metal ions to adsorb and desorb for five consecutive cycles. Therefore, the developed biodegradable film offers the potential for remediation of specified metal ions.

NAD+-associated-hyaluronic acid and poly(L-lysine) polyelectrolyte complexes: An evaluation of their potential for ocular drug delivery

This study details the formation and characterisation of a novel nicotinamide adenine dinucleotide (NAD+)-associated polymeric nanoparticle system. The development of a polyelectrolyte complex (PEC) composed of two natural polyelectrolytes, hyaluronic acid and poly(L-lysine), and an evaluation of its suitability for NAD+ ocular delivery, primarily based on its physicochemical properties and in vitro release profile under physiological ocular flow rates, were of key focus. Following optimisation of formulation method conditions such as complexation pH, mode of addition, and charge ratio, the PEC was successfully formulated under mild formulation conditions via polyelectrolyte complexation. With a size of 235.1 ± 19.0 nm, a PDI value of 0.214 ± 0.140, and a zeta potential value of - 38.0 ± 1.1 mV, the chosen PEC, loaded with 430 µg of NAD+ per mg of PEC, exhibited non-Fickian, sustained release at physiological flowrates of 10.9 ± 0.2 mg of NAD+ over 14 h. PECs containing up to 200 µM of NAD+ did not induce any significant cytotoxic effects on an immortalised human corneal epithelial cell line. Using fluorescent labeling, the NAD+-associated PECs demonstrated retention within the corneal epithelium layer of a porcine model up to 6 h post incubation under physiological conditions. A study of the physicochemical behaviour of the PECs, in terms of size, zeta potential and NAD+ complexation in response to environmental stimuli,highlighted the dynamic nature of the PEC matrix and its dependence on both pH and ionic condition. Considering the successful formation of reproducible NAD+-associated PECs with suitable characteristics for ocular drug delivery via an inexpensive formulation method, they provide a promising platform for NAD+ ocular delivery with a strong potential to improve ocular health.

β-Escin: An Updated Review of Its Analysis, Pharmacology, Pharmacokinetics, and Toxicity

[Formula: see text]-Escin is an oleanane-type pentacyclic triterpenoid saponin extracted from the seeds of Aesculus hippocastanum (AH), which is more widely distributed. [Formula: see text]-Escin sodium has been approved by the American FDA for clinical usage. This paper is intended to summarize an updated and comprehensive review of the pharmacological activities, pharmacokinetic properties, toxicity, and analytical methods of [Formula: see text]-escin. Studies have shown that [Formula: see text]-escin has significant antitumor, antiviral, anti-inflammatory, and other activities alongside less adverse effects and higher safety than other compounds. The review shows that the pharmacological effects of [Formula: see text]-escin involve mechanisms such as ATM/[Formula: see text]H2AX, RhoA/Rock, GSK-3[Formula: see text]/[Formula: see text]-Catenin, HER2/HER3/Akt, and PI3K/Akt signaling pathways, and Cyclin A, p21[Formula: see text], survivin, Bcl-2, Mcl-1, Caspases, TGF-[Formula: see text], MMPs, and TNF-[Formula: see text] among other inflammatory factors. [Formula: see text]-Escin has significant cytotoxicity; the use of the chitosan/xanthan gum-based polyelectrolyte complexes PA1 and PC-11 to modify it not only to reduces its toxicity, but also improves its drug efficacy. Because of this, these compounds may become a new research hotspot. [Formula: see text]-Escin in vivo metabolism can be converted by the CYP1A2 enzyme in the intestinal flora to produce [Formula: see text]-escin, deacylated, deglycosylated, and 21[Formula: see text]-[Formula: see text]-crotonoyl-protoescin, and the binding rate of the plasma proteins is higher than 90%. These are mainly metabolized by the liver, kidneys, and other organs, and excreted in the form of urine and feces. The number of reports on the specific mediators of the metabolism of [Formula: see text]-escin and their mechanisms and metabolites is relatively small; furthermore, the results are vague. Therefore, a complete and in-depth exploration of the pharmacokinetic characteristics of [Formula: see text]-escin is needed to provide a more complete and effective theoretical reference for the study of its pharmacodynamic activity.

Modeling of in vitro drug release from polymeric microparticle carriers

Incorporation of active substances in polymeric microparticles (microencapsulation) is an important technological strategy used in the pharmaceutical industry to improve the functionality, quality, safety and/or therapeutic efficiency of pharmaceutical preparations for different routes of administration. The current focus of research in this field is on the encapsulation of small molecules and macromolecules into microparticles based on biocompatible synthetic polymers and biopolymers, such as polypeptides and polysaccharides, in order to achieve preferable drug release kinetics and many other advantages. Diversity in the structure and size of microparticles, choice of polymers, and manufacturing processes, allows for designing a multitude of microcarriers (e.g., monolithic matrix microspheres, hollow microcapsules, water-or oil-core microcapsules, stimulus-sensitive microcapsules), whereby their impact on biopharmaceutical profile of drugs can be manipulated. The results so far indicate that the in vitro drug release kinetics evaluation is one of the key aspects of the microparticle-type carrier characterization, where the application of the mathematical analysis (modeling) of the drug release profiles is an important tool for elucidating drug release mechanisms, as well as for evaluating the influence and optimization of formulation and process parameters in the microencapsulation procedure. The article reviews representative studies in which mathematical modeling of experimentally obtained release data was performed for microencapsulated model drugs with different physicochemical properties, as well as the relevance and potential limitations of this approach.