Polysaccharide Chemistry in Drug Delivery, Endocrinology, and Vaccines

Preparation and Characterization of Silica-Coated Sodium Alginate Hydrogel Beads and the Delivery of Curcumin

In this study, to address the defects of sodium alginate (SA), such as its susceptibility to disintegration, silica was coated on the outer layer of sodium alginate hydrogel beads in order to improve its swelling and slow-release properties. Tetraethyl orthosilicate (TEOS) was used as the hydrolyzed precursor, and the solution of silica precursor was prepared by sol-gel reaction under acidic conditions. Then SA-silica hydrogel beads prepared by ionic crosslinking method were immersed into the SiO2 precursor solution to prepare SA-silica hydrogel beads. The chemical structure and morphology of the hydrogel beads were characterized by XRD, FTIR, and SEM, and the results showed that the surface of SA-silica beads was successfully encapsulated with the outer layer of SiO2, and the surface was smooth and dense. The swelling experiments showed that the swelling performance effectively decreased with the increase of TEOS molar concentration, and the maximum swelling ratio of the hydrogel beads decreased from 41.07 to 14.3, and the time to reach the maximum swelling ratio was prolonged from 4 h to 8 h. The sustained-release experiments showed that the SA-silica hydrogel beads possessed a good pH sensitivity, and the time of sustained-release was significantly prolonged in vitro. Hemolysis and cytotoxicity experiments showed that the SA-silica hydrogel beads were biocompatible when the TEOS molar concentration was lower than 0.375 M. The SA-silica-2 hydrogel beads had good biocompatibility, swelling properties, and slow-release properties at the same time.

Using Carbohydrate-Based Polymers to Facilitate Testicular Regeneration

Male infertility is a significant global issue affecting 60-80 million people, with 40%-50% of cases linked to male issues. Exposure to radiation, drugs, sickness, the environment, and oxidative stress may result in testicular degeneration. Carbohydrate-based polymers (CBPs) restore testis differentiation and downregulate apoptosis genes. CBP has biodegradability, low cost, and wide availability, but is at risk of contamination and variations. CBP shows promise in wound healing, but more research is required before implementation in healthcare. Herein, we discuss the recent advances in engineering applications of CBP employed as scaffolds, drug delivery systems, immunomodulation, and stem cell therapy for testicular regeneration. Moreover, we emphasize the promising challenges warranted for future perspectives.

Threading the needle: Achieving simplicity and performance in cellulose alkanoate ω-carboxyalkanoates for amorphous solid dispersion

Most active pharmaceutical ingredients (APIs) suffer from poor water solubility, often keeping them from reaching patients. To overcome the issues of poor drug solubility and subsequent low bioavailability, amorphous solid dispersions (ASDs) have garnered much attention. Cellulose ester derivatives are of interest for ASD applications as they are benign, sustainable-based, and successful in commercial drug delivery systems, e.g. in osmotic pump systems and as commercial ASD polymers. Synthesis of carboxy-pendant cellulose esters is a challenge, due in part to competing reactions between carboxyls and hydroxyls, forming ester crosslinks. Herein we demonstrate proof-of-concept for a scalable synthetic route to simple, yet highly promising ASD polymers by esterifying cellulose polymers through ring-opening of cyclic succinic or glutaric anhydride. We describe the complexity of such ring-opening reactions, not previously well-described, and report ways to avoid gelation. We report synthesis, characterization, and preliminary in vitro ASD evaluations of fifteen such derivatives. Synthetic routes were designed to accommodate these criteria: no protecting groups, no metal catalysts, mild conditions with standard reagents, simple purification, and one-pot synthesis. Finally, these designed ASD polymers included members that maintained fast-crystallizing felodipine in solution and release it from an ASD at rather high 20 % drug loading (DL).

The effect of the molecular structure of hydroxypropyl methylcellulose on the states of water, wettability, and swelling properties of cryogels prepared with and without CaO2

Hydroxypropyl methylcellulose (HPMC) belongs to the cellulose ether family that has hydroxyl groups substituted by hydrophobic methyl groups (DS) and hydrophilic hydroxypropyl groups (MS). Herein, the interactions between water molecules and cryogels prepared with HPMC in the presence and absence of a linear nonionic surfactant, as well as CaO₂ microparticles, which react with water producing O₂, were systematically investigated by sorption experiments and Time-Domain Nuclear Magnetic Resonance. Regardless of the DS and MS, most water molecules presented transverse relaxation time t2 typical of intermediate water and a small population of more tightly bound water. HPMC cryogels with the highest DS of 1.9 presented the slowest swelling rate of 0.519 ± 0.053 g_water/(g.s) and the highest contact angle values 85.250^o ± 0.004^o, providing the best conditions for a slow reaction between CaO₂ and water. The presence of surfactant favored hydrophobic interactions that allowed the polar head of the surfactant to be exposed to the medium, resulting in a higher swelling rate and lower contact angle values. The HPMC with the highest MS presented the fastest swelling rate and the lowest contact angle. These findings are relevant for the formulations and reactions, where tuning the swelling kinetics is crucial for the final application.

Structural characterization, antioxidant activity, and the effects of Codonopsis pilosula polysaccharides on the solubility and stability of flavonoids

Codonopsis pilosula (CP) possesses properties related to nourishing the spleen and stomach, and tonifying Qi of the stomach and mind in traditional Chinese medicine (TCM). Codonopsis pilosula polysaccharides (CPPS), which are the primary active components of CP, are thought to be in charge of their extensive use. Rutin, quercetin, luteoloside, and luteolin, are common and pharmacologically significant flavonoids with many pharmacological activities, but their oral bioavailability is limited by poor solubility and stability. In this study, high-performance gel permeation chromatography (HPGPC) estimated the molecular weight of CPPS to be 9.7 × 10⁵ Da. Sugar analysis revealed that CPPS is composed of D-mannose, D-glucose, and D-xylose with a molar ratio of 5.8:1.9:1.0. Moreover, the antioxidant test showed that CPPS had good antioxidant activity. It is worth noting that CPPS integrated the four flavonoids to form a spongy compound that significantly increased the solubilities and stabilities of flavonoids. The bonding constants of the CPPS and flavonoid-derived inclusion complexes ranged from 60 L mol^-1 to 2,030,816 L mol^-1, which demonstrated the capacity of CPPS to interact with flavonoids intermolecularly to form a drug complex system, resulting in potentially enhanced biopharmaceutical properties of flavonoids. This finding could provide a reference point for further applications of polysaccharides from herbal medicines.

Smart Phototheranostics based on Carbon Nanohorns for Precise Imaging-Guided Post-PDT toward Residual Tumor Cells after Initial Phototherapy

As promising photonic material, phototheranostics can be activated in the laser irradiation range of tumor with sensitivity and spatiotemporal precision. However, it is difficult to completely eradicate solid tumors due to their irregularity and limited laser irradiation area. Herein, multi-stimulus responsive HA-Ce6@SWNHs were constructed with single-walled carbon nanohorns (SWNHs) and chlorine e6 (Ce6) modified hyaluronic acid (HA) via non-covalent binding. This SWNHs-based phototheranostics not only exhibited water dispersion but also could target tumor and be activated by near-infrared light for photodynamic therapy (PDT) and photothermal therapy (PTT). Additionally, HA-Ce6@SWNHs could be degraded by hyaluronidase in residual tumor cells, causing HA-Ce6 to fall off the SWNHs surfaces to restore autofluorescence, thus precisely guiding the programmed photodynamic treatments for residual tumor cells after the initial phototherapy. Thus, this work provides a rationally designed multiple-stimulus-response strategy to develop smart SWNHs-based phototheranostics for precise PDT/PTT and post-treatment imaging-guided PDT of residual tumor cells.

Sustainable Biodegradable Biopolymer-Based Nanoparticles for Healthcare Applications

Biopolymeric nanoparticles are gaining importance as nanocarriers for various biomedical applications, enabling long-term and controlled release at the target site. Since they are promising delivery systems for various therapeutic agents and offer advantageous properties such as biodegradability, biocompatibility, non-toxicity, and stability compared to various toxic metal nanoparticles, we decided to provide an overview on this topic. Therefore, the review focuses on the use of biopolymeric nanoparticles of animal, plant, algal, fungal, and bacterial origin as a sustainable material for potential use as drug delivery systems. A particular focus is on the encapsulation of many different therapeutic agents categorized as bioactive compounds, drugs, antibiotics, and other antimicrobial agents, extracts, and essential oils into protein- and polysaccharide-based nanocarriers. These show promising benefits for human health, especially for successful antimicrobial and anticancer activity. The review article, divided into protein-based and polysaccharide-based biopolymeric nanoparticles and further according to the origin of the biopolymer, enables the reader to select the appropriate biopolymeric nanoparticles more easily for the incorporation of the desired component. The latest research results from the last five years in the field of the successful production of biopolymeric nanoparticles loaded with various therapeutic agents for healthcare applications are included in this review.

Polysaccharides for Medical Technology: Properties and Applications

Over the past decade, the use of polysaccharides has gained tremendous attention in the field of medical technology. They have been applied in various sectors such as tissue engineering, drug delivery system, face mask, and bio-sensing. This review article provides an overview and background of polysaccharides for biomedical uses. Different types of polysaccharides, for example, cellulose and its derivatives, chitin and chitosan, hyaluronic acid, alginate, and pectin are presented. They are fabricated in various forms such as hydrogels, nanoparticles, membranes, and as porous mediums. Successful development and improvement of polysaccharide-based materials will effectively help users to enhance their quality of personal health, decrease cost, and eventually increase the quality of life with respect to sustainability.

An insight on topically applied formulations for management of various skin disorders

Various types of skin disorders across each age group and in each part of geographical world are very dreadful. Despite not being fatal each time they are always of social and mental concern for suffering individuals, causing complications in millions of patients every day and require comparatively longer duration of treatment. Off late, various topical/transdermal formulations have been widely explored for the treatment of various skin ailments. The efficiency of topical therapy depends on various physiochemical properties of drugs like particle size, particle size distribution, partition coefficient, viscosity of dosage form, skin permeability, skin condition and the site of application. Therefore, in plenty of examples, long-acting topical formulations have shown to be markedly excellent in comparison to conventional dosage forms. The major advantages of topical formulations accrue from their demonstrated ability: (i) Reduced serious side effects that may occur due to undesirably higher systemic absorption of drug. (ii) Enhancement of drug accumulation at the desired site. (iii) Easy incorporation of enormous range of hydrophilic and hydrophobic drugs and (iv) Reduced risk of dose dumping and comparatively easy termination of drug release. The prospective applications of topically applied formulations and the deposition of pharmaceuticals into the skin are examined.