Controlled release of 5-fluorouracil to melanoma cells using a hydrogel/micelle composites based on deoxycholic acid and carboxymethyl chitosan

Facile fabrication of temperature/pH dual sensitive hydrogels based on cellulose and polysuccinimide through aqueous amino-succinimide reaction

A temperature/pH dual sensitive hydrogel with a semi-interpenetrating network (semi-IPN) structure was synthesized through an aqueous amino-succinimide reaction between water-soluble polysuccinimide and polyethyleneimine in the presence of thermosensitive cellulose derivatives. Single-factor experiments were carried out to optimize the preparation conditions of the semi-IPN hydrogel. The swelling behavior and cytotoxicity assay of the hydrogel were tested. Finally, taking 5- fluorouracil (5-Fu) as a model drug, the release performance of the 5-Fu-loaded hydrogel was investigated. The results indicated that the swelling ratio (SR) first decreased and then increased when the pH of the solutions ascended from 2 to 10. The SR decreased with the increase in temperature. In addition, the swelling behavior of the hydrogel was reversible and reproducible under different pH values and temperatures. The prepared hydrogels had good cytocompatibility. The release behavior of 5-Fu was most consistent with the Korsmeyer-Peppas model and followed the case II diffusion. The acidic environment was beneficial for the release of 5-Fu. The preparation process of the semi-IPN hydrogel is simple and the reaction can proceed quickly in water. The strategy introduced here has great potential for application in the preparation of drug carriers.

Aldehyde group pendant-grafted pectin-based injectable hydrogel

Periodate oxidation has been the widely accepted route for obtaining aldehyde group-functionalized polysaccharides but significantly influenced the various physicochemical properties due to the ring opening of the backbone of polysaccharides. The present study, for the first time, presents a novel method for the preparation of aldehyde group-functionalized polysaccharides that could retain the ring structure and the consequent rigidity of the backbone. Pectin was collected as the representative of polysaccharides and modified with cyclopropyl formaldehyde to obtain pectin aldehyde (AP), which was further crosslinked by DL-lysine (LYS) via the Schiff base reaction to prepare injectable hydrogel. The feasibility of the functionalization was proved by FT-IR and 1H NMR techniques. The obtained hydrogel showed acceptable mechanical properties, self-healing ability, syringeability, and sustained-release performance. Also, as-prepared injectable hydrogel presented great biocompatibility with a cell proliferation rate of 96 %, and the drug-loaded hydrogel exhibited clear inhibition of cancer cell proliferation. Overall, the present study showed a new method for the preparation of aldehyde group-functionalized polysaccharides, and the drug-loaded hydrogel has potential in drug release applications.

The anticancer activity of bile acids in drug discovery and development

Bile acids (BAs) constitute essential components of cholesterol metabolites that are synthesized in the liver, stored in the gallbladder, and excreted into the intestine through the biliary system. They play a crucial role in nutrient absorption, lipid and glucose regulation, and the maintenance of metabolic homeostasis. In additional, BAs have demonstrated the ability to attenuate disease progression such as diabetes, metabolic disorders, heart disease, and respiratory ailments. Intriguingly, recent research has offered exciting evidence to unveil their potential antitumor properties against various cancer cell types including tamoxifen-resistant breast cancer, oral squamous cell carcinoma, cholangiocarcinoma, gastric cancer, colon cancer, hepatocellular carcinoma, prostate cancer, gallbladder cancer, neuroblastoma, and others. Up to date, multiple laboratories have synthesized novel BA derivatives to develop potential drug candidates. These derivatives have exhibited the capacity to induce cell death in individual cancer cell types and display promising anti-tumor activities. This review extensively elucidates the anticancer activity of natural BAs and synthetic derivatives in cancer cells, their associated signaling pathways, and therapeutic strategies. Understanding of BAs and their derivatives activities and action mechanisms will evidently assist anticancer drug discovery and devise novel treatment.

Acylhydrazone-derived whole pectin-based hydrogel as an injectable drug delivery system

Injectable hydrogel-based drug delivery systems have attracted more and more attention due to their sustained-release performance, biocompatibility, and 3D network. The present study showed whole pectin-based hydrogel as an injectable drug delivery system, which was developed from oxidized pectin (OP) and diacylhydrazine adipate-functionalized pectin (Pec-ADH) via acylhydrazone linkage. The as-prepared hydrogels were characterized by 1H NMR, FT-IR, and SEM techniques. The equilibrium swelling ratio of obtained hydrogel (i.e., sample gel 5) was up to 4306.65 % in the distilled water, which was higher than that in PBS with different pH values. Increasing the pH of the swelling media, the swelling ratio of all hydrogels decreased significantly. The results that involved the swelling properties indicated the salt- and pH-responsiveness of the as-prepared hydrogels. The drug release study presented that 5-FU can be persistently released for more than 12 h without sudden release. Moreover, the whole pectin-based hydrogel presented high cytocompatibility toward L929 cell lines, and the drug delivery system showed a high inhibitory effect on MCF-7 cell lines. All these results manifested that the acylhydrazone-derived whole pectin-based hydrogel was an excellent candidate for injectable drug delivery systems.

Gel Formulations for Topical Treatment of Skin Cancer: A Review

Skin cancer, with all its variations, is the most common type of cancer worldwide. Chemotherapy by topical application is an attractive strategy because of the ease of application and non-invasiveness. At the same time, the delivery of antineoplastic agents through the skin is difficult because of their challenging physicochemical properties (solubility, ionization, molecular weight, melting point) and the barrier function of the stratum corneum. Various approaches have been applied in order to improve drug penetration, retention, and efficacy. This systematic review aims at identifying the most commonly used techniques for topical drug delivery by means of gel-based topical formulations in skin cancer treatment. The excipients used, the preparation approaches, and the methods characterizing gels are discussed in brief. The safety aspects are also highlighted. The combinatorial formulation of nanocarrier-loaded gels is also reviewed from the perspective of improving drug delivery characteristics. Some limitations and drawbacks in the identified strategies are also outlined and considered within the future scope of topical chemotherapy.

In situ administration of temperature-sensitive hydrogel composite loading paclitaxel microspheres and cisplatin for the treatment of melanoma

Chemotherapy is one of the main therapeutic strategies for the treatment of malignant melanoma. Conventional chemotherapeutic agents often lack targeting abilities, and efficacy is hampered by their high toxic effects to normal tissues and rapid clearance from the circulation. In this study, porous paclitaxel (PTX)-loaded polylactide (PLA) microspheres (PPMSs) were prepared by a modified double-emulsion-solvent evaporation method. In addition, PPMSs and cisplatin (DDP) were co-embedded in a thermosensitive hydrogel to construct a dual-drug co-delivery hydrogel system (PPMSs/DDP@Gel) for in-situ chemotherapy to treat melanoma by means of an intra-tumoral injection. The system allows for the sustained release of two drugs and exhibits good temperature-sensitive properties. In vitro antitumor activity showed that this hydrogel composite can induce B16 cell apoptosis and inhibit its migration. In vivo, anti-tumor studies have shown that the PPMSs/DDP@Gel significantly inhibited tumor growth, prolonged the survival of tumor-bearing mice, and had no obvious toxic side effects on major organs. Furthermore, immunohistochemical analysis revealed that PPMSs/DDP@Gel significantly inhibited tumor cell proliferation and promoted apoptosis of tumor cells. Taken together, the injectable temperature-sensitive PPMSs/DDP@Gel is a promising candidate for the local treatment of melanoma.

A Review on Biomedical Application of Polysaccharide-Based Hydrogels with a Focus on Drug Delivery Systems

Over the last years of research on drug delivery systems (DDSs), natural polymer-based hydrogels have shown many scientific advances due to their intrinsic properties and a wide variety of potential applications. While drug efficacy and cytotoxicity play a key role, adopting a proper DDS is crucial to preserve the drug along the route of administration and possess desired therapeutic effect at the targeted site. Thus, drug delivery technology can be used to overcome the difficulties of maintaining drugs at a physiologically related serum concentration for prolonged periods. Due to their outstanding biocompatibility, polysaccharides have been thoroughly researched as a biological material for DDS advancement. To formulate a modified DDS, polysaccharides can cross-link with different molecules, resulting in hydrogels. According to our recent findings, targeted drug delivery at a certain spot occurs due to external stimulation such as temperature, pH, glucose, or light. As an adjustable biomedical device, the hydrogel has tremendous potential for nanotech applications in involved health areas such as pharmaceutical and biomedical engineering. An overview of hydrogel characteristics and functionalities is provided in this review. We focus on discussing the various kinds of hydrogel-based systems on their potential for effectively delivering drugs that are made of polysaccharides.

Advances in the Application of Nanomaterials to the Treatment of Melanoma

Melanoma can be divided into cutaneous melanoma, uveal melanoma, mucosal melanoma, etc. It is a very aggressive tumor that is prone to metastasis. Patients with metastatic melanoma have a poor prognosis and shorter survival. Although current melanoma treatments have been dramatically improved, there are still many problems such as systemic toxicity and the off-target effects of drugs. The use of nanoparticles may overcome some inadequacies of current melanoma treatments. In this review, we summarize the limitations of current therapies for cutaneous melanoma, uveal melanoma, and mucosal melanoma, as well as the adjunct role of nanoparticles in different treatment modalities. We suggest that nanomaterials may have an effective intervention in melanoma treatment in the future.

Aggressive strategies for regenerating intervertebral discs: stimulus-responsive composite hydrogels from single to multiscale delivery systems

As our research on the physiopathology of intervertebral disc degeneration (IVD degeneration, IVDD) has advanced and tissue engineering has rapidly evolved, cell-, biomolecule- and nucleic acid-based hydrogel grafting strategies have been widely investigated for their ability to overcome the harsh microenvironment of IVDD. However, such single delivery systems suffer from excessive external dimensions, difficult performance control, the need for surgical implantation, and difficulty in eliminating degradation products. Stimulus-responsive composite hydrogels have good biocompatibility and controllable mechanical properties and can undergo solution-gel phase transition under certain conditions. Their combination with ready-to-use particles to form a multiscale delivery system may be a breakthrough for regenerative IVD strategies. In this paper, we focus on summarizing the progress of research on the stimulus response mechanisms of regenerative IVD-related biomaterials and their design as macro-, micro- and nanoparticles. Finally, we discuss multi-scale delivery systems as bioinks for bio-3D printing technology for customizing personalized artificial IVDs, which promises to take IVD regenerative strategies to new heights.

Synthesis and Characterization of Chitosan-Decorated Nanoemulsion Gel of 5-Fluorouracil for Topical Delivery

(1) Background: The present study aimed to prepare chitosan-coated nanoemulsion gel containing 5-fluorouracil for enhanced topical delivery. (2) Methods: To formulate the nanoemulsion gel, oleic acid was used as the oil phase and Carbopol 940 as a gelling agent. Chitosan was used as a coating agent to control the release of 5-FU. Drug−excipient compatibility was evaluated using ATR-FTIR. The prepared nanoemulsion formulations were characterized based on particle size distribution, zeta potential, % encapsulation efficiency and drug content. In vitro drug release, skin drug retention and ex vivo permeation profiles were performed across rat skin using a Franz diffusion cell. Skin irritation experiments were also conducted on rats to examine the irritation potential of the formulations. (3) Results: It was found that the drug and excipients were compatible and chitosan successfully coated 5-FU, as demonstrated by ATR-FTIR results. The introduction of chitosan increased the size and zeta potential of the nanoemulsion. The 5-FU release in vitro was significantly lowered in the case of chitosan-decorated nanoemulsion (5-FU-C-NE), whereas the permeation and skin drug retention were higher in the case of 5-FU-C-NE. The formulations were proven non-irritant to the skin of the rats. The optimized formulation of the nanoemulsion was introduced into 1% Carbopol 940 gel. Incorporating the nanoemulsion into the gel further reduced the drug release in vitro and ex vivo permeation, whereas the retention of the drug in the skin was significantly increased (ANOVA; p < 0.05). The increase in skin retention was due to the presence of chitosan and Carbopol 940. The in vitro and ex vivo results were also confirmed with in vivo studies. Incorporating nanoemulsion into gel has resulted in higher Tmax, longer half-life and greater skin drug retention. (4) Conclusion: The results suggest that chitosan-decorated nanoemulsion gel is safe and can potentially be used to promote 5-FU skin retention, which is ideal for skin diseases such as melanoma.