Tamoxifen-loaded thiolated alginate-albumin nanoparticles as antitumoral drug delivery systems

Polysaccharide-Drug Conjugates: A Tool for Enhanced Cancer Therapy

Cancer is one of the most widespread deadly diseases, following cardiovascular disease, worldwide. Chemotherapy is widely used in combination with surgery, hormone and radiation therapy to treat various cancers. However, chemotherapeutic drugs can cause severe side effects due to non-specific targeting, poor bioavailability, low therapeutic indices, and high dose requirements. Several drug carriers successfully overcome these issues and deliver drugs to the desired sites, reducing the side effects. Among various drug delivery systems, polysaccharide-based carriers that target only the cancer cells have been developed to overcome the toxicity of chemotherapeutics. Polysaccharides are non-toxic, biodegradable, hydrophilic biopolymers that can be easily modified chemically to improve the bioavailability and stability for delivering therapeutics into cancer tissues. Different polysaccharides, such as chitosan, alginates, cyclodextrin, pullulan, hyaluronic acid, dextran, guar gum, pectin, and cellulose, have been used in anti-cancer drug delivery systems. This review highlights the recent progress made in polysaccharides-based drug carriers in anti-cancer therapy.

Paclitaxel-Loaded Folate-Targeted Albumin-Alginate Nanoparticles Crosslinked with Ethylenediamine. Synthesis and In Vitro Characterization

Among the different ways to reduce the secondary effects of antineoplastic drugs in cancer treatment, the use of nanoparticles has demonstrated good results due to the protection of the drug and the possibility of releasing compounds to a specific therapeutic target. The α-isoform of the folate receptor (FR) is overexpressed on a significant number of human cancers; therefore, folate-targeted crosslinked nanoparticles based on BSA and alginate mixtures and loaded with paclitaxel (PTX) have been prepared to maximize the proven antineoplastic activity of the drug against solid tumors. Nanometric-range-sized particles (169 ± 28 nm-296 ± 57 nm), with negative Z-potential values (between -0.12 ± 0.04 and -94.1± 0.4), were synthesized, and the loaded PTX (2.63 ± 0.19-3.56 ±0.13 µg PTX/mg Np) was sustainably released for 23 and 27 h. Three cell lines (MCF-7, MDA-MB-231 and HeLa) were selected to test the efficacy of the folate-targeted PTX-loaded BSA/ALG nanocarriers. The presence of FR on the cell membrane led to a significantly larger uptake of BSA/ALG-Fol nanoparticles compared with the equivalent nanoparticles without folic acid on their surface. The cell viability results demonstrated a cytocompatibility of unloaded nanoparticle-Fol and a gradual decrease in cell viability after treatment with PTX-loaded nanoparticle-Fol due to the sustainable PTX release.

Recent Advances in Improved Anticancer Efficacies of Camptothecin Nano-Formulations: A Systematic Review

Camptothecin (CPT), a natural plant alkaloid, has indicated potent antitumor activities via targeting intracellular topoisomerase I. The promise that CPT holds in therapies is restricted through factors that include lactone ring instability and water insolubility, which limits the drug oral solubility and bioavailability in blood plasma. Novel strategies involving CPT pharmacological and low doses combined with nanoparticles have indicated potent anticancer activity in vitro and in vivo. This systematic review aims to provide a comprehensive and critical evaluation of the anticancer ability of nano-CPT in various cancers as a novel and more efficient natural compound for drug development. Studies were identified through systematic searches of PubMed, Scopus, and ScienceDirect. Eligibility checks were performed based on predefined selection criteria. Eighty-two papers were included in this systematic review. There was strong evidence for the association between antitumor activity and CPT treatment. Furthermore, studies indicated that CPT nano-formulations have higher antitumor activity in comparison to free CPT, which results in enhanced efficacy for cancer treatment. The results of our study indicate that CPT nano-formulations are a potent candidate for cancer treatment and may provide further support for the clinical application of natural antitumor agents with passive targeting of tumors in the future.

Novel Tamoxifen Nanoformulations for Improving Breast Cancer Treatment: Old Wine in New Bottles

Breast cancer (BC) is one of the leading causes of death from cancer in women; second only to lung cancer. Tamoxifen (TAM) is a hydrophobic anticancer agent and a selective estrogen modulator (SERM), approved by the FDA for hormone therapy of BC. Despite having striking efficacy in BC therapy, concerns regarding the dose-dependent carcinogenicity of TAM still persist, restricting its therapeutic applications. Nanotechnology has emerged as one of the most important strategies to solve the issue of TAM toxicity, owing to the ability of nano-enabled-formulations to deliver smaller concentrations of TAM to cancer cells, over a longer period of time. Various TAM-containing-nanosystems have been successfully fabricated to selectively deliver TAM to specific molecular targets found on tumour membranes, reducing unwanted toxic effects. This review begins with an outline of breast cancer, the current treatment options and a history of how TAM has been used as a combatant of BC. A detailed discussion of various nanoformulation strategies used to deliver lower doses of TAM selectively to breast tumours will then follow. Finally, a commentary on future perspectives of TAM being employed as a targeting vector, to guide the delivery of other therapeutic and diagnostic agents selectively to breast tumours will be presented.

Development of Microspheres Based on Thiol-Modified Sodium Alginate for Intestinal-Targeted Drug Delivery

Bioactive peptide drugs are mostly delivered by parenteral administration, which brings great pain and risks to patients. Oral administration is an acceptable alternative form. However, peptide drugs are extremely sensitive to the strong acidic environment in the stomach after oral administration. They would be degraded by pepsin and trypsin in the gastrointestinal tract. Herein, we present microspheres for intestinal-targeted peptides drug delivery through oral administration. Sodium alginate was reacted with l-cysteine to bring it into thiol groups. Then sodium alginate-l-cysteine conjugates were mixed with native sodium alginate and emulsified by an improved method. Ca²⁺ was used to fix the emulsion to get the microspheres. Bovine serum albumin was used as the simulating drug to assess the feasibility of microspheres as intestinal delivery carriers. The results showed that the microspheres exhibited spherical properties and narrow size distribution. The drug-loading capacity of microspheres was not compromised after thiol-modification. It is interesting that the microspheres can maintain structural integrity and hold drugs in the strong acidic environment in the stomach. Conversely, the microspheres presented sustained intestinal-targeted drugs release ability as expected. Moreover, thiol-modification further improved the adherence ability of microspheres on the inner walls of the small intestine, which is good for enhancing drug permeability. In sum, the microspheres based on thiol-modified sodium alginate have promising applications as intestinal-targeted macromolecular drug carriers.

Thiolated polymers: Bioinspired polymers utilizing one of the most important bridging structures in nature

Thiolated polymers designated "thiomers" are obtained by covalent attachment of thiol functionalities on the polymeric backbone of polymers. In 1998 these polymers were first described as mucoadhesive and in situ gelling compounds forming disulfide bonds with cysteine-rich substructures of mucus glycoproteins and crosslinking through inter- and intrachain disulfide bond formation. In the following, it was shown that thiomers are able to form disulfides with keratins and membrane-associated proteins exhibiting also cysteine-rich substructures. Furthermore, permeation enhancing, enzyme inhibiting and efflux pump inhibiting properties were demonstrated. Because of these capabilities thiomers are promising tools for drug delivery guaranteeing a strongly prolonged residence time as well as sustained release on mucosal membranes. Apart from that, thiomers are used as drugs per se. In particular, for treatment of dry eye syndrome various thiolated polymers are in development and a first product has already reached the market. Within this review an overview about the thiomer-technology and its potential for different applications is provided discussing especially the outcome of studies in non-rodent animal models and that of numerous clinical trials. Moreover, an overview on product developments is given.

Natural product-based nanoformulations for cancer therapy: Opportunities and challenges

Application of natural product-based nanoformulations for the treatment of different human diseases, such as cancer, is an emerging field. The conventional cancer therapeutic modalities, including surgery, chemotherapy, immunotherapy, radiotherapy has limited achievements. A larger number of drawbacks are associated with these therapies, including damage to proliferating healthy tissues, structural deformities, systemic toxicity, long-term side effects, resistance to the drug by tumor cells, and psychological problems. The advent of nanotechnology in cancer therapeutics is recent; however, it has progressed and transformed the field of cancer treatment at a rapid rate. Nanotherapeutics have promisingly overcome the limitations of conventional drug delivery system, i.e., low aqueous solubility, low bioavailability, multidrug resistance, and non-specificity. Specifically, natural product-based nanoformulations are being intentionally studied in different model systems. Where it is found that these nanoformulations has more proximity and reduced side effects. The nanoparticles can specifically target tumor cells, enhancing the specificity and efficacy of cancer therapeutic modalities which in turn improves patient response and survival. The integration of phytotherapy and nanotechnology in the clinical setting may improve pharmacological response and better clinical outcome of patients.

Biocompatible disulphide cross-linked sodium alginate derivative nanoparticles for oral colon-targeted drug delivery

The application of layer-by-layer (LbL) approach on nanoparticle surface coating improves the colon-specific drug delivery of insoluble drugs. Here, we aimed to formulate a self-assembled cysteamine-based disulphide cross-linked sodium alginate with LbL self-assembly to improve the delivery of paclitaxel (PCX) to colonic cancer cells. Cysteamine was conjugated to the backbone of oxidized SA to form a core of self-assembled disulphide cross-linked nanospheres. P3DL was selected for PCX loading and fabricated LbL with poly(allylamine hydrochloride) (PAH) and poly(4-styrenesulfonic acid-co-maleic acid) sodium salt (PSSCMA) resulting from characterization and drug release studies. P3DL-fabricated PCX-loaded nanospheres (P3DL/PAH/PSSCMA) exhibited an encapsulation efficiency of 77.1% with cumulative drug release of 45.1%. Dynamic light scattering analysis was reported at 173.6 ± 2.5 nm with polydispersity index of 0.394 ± 0.105 (zeta potential= -58.5 mV). P3DL/PAH/PSSCMA demonstrated a pH-dependent swelling transition; from pH 1 to 7 (102.2% increase). The size increased by 33.0% in reduction response study after incubating with 10 mM glutathione (day 7). HT-29 cells showed high viabilities (86.7%) after treatment with the fabricated nanospheres at 0.8 µg/mL. Cellular internalization was successful with more than 70.0% nanospheres detected in HT-29 cells. Therefore, this fabricated nanospheres may be considered as potential nanocarriers for colon cancer-targeted chemotherapeutic drug delivery.

Aptamer functionalized curcumin-loaded human serum albumin (HSA) nanoparticles for targeted delivery to HER-2 positive breast cancer cells

In this study, an HER2 aptamer-decorated curcumin-loaded human serum albumin nanoparticle (Apt-HSA/CCM NP) was developed and characterized as a new anticancer formulation for targeted delivery to human epithelial growth factor receptor 2 (HER2) overexpressing breast cancer cells. Conjugation of HER2 Apt to the surface of HSA NPs was confirmed by gel electrophoresis and FTIR analysis. The obtained NPs have the hydrodynamic diameter of 281.1 ± 11.1 nm and zeta potential of -33.3 ± 2.5 mV. The data demonstrated that encapsulation of curcumin in HSA NPs by desolvation method has increased water solubility by 400 folds. Fluorescent microscopy image demonstrated remarkable cytoplasmic uptake of Apt-HSA/CCM NPs in HER2-overexpressing SK-BR-3 cells compared to unconjugated counterparts. Cytotoxicity experiments demonstrated no significant difference between cytotoxic effect of free curcumin and non-targeted HSA/CCM NPs in both HER2 positive and HER2 negative cell lines. However, the toxicity of Apt-HSA/CCM NPs was significantly higher and cell viability reached 36% after 72 h in SK-BR3 cell line. These results suggest that this targeted delivery system has the potential to be considered as a promising candidate for the treatment of HER2 positive cancer cells.

Biocompatibility studies of intravenously administered ionic-crosslinked chitosan-BSA nanoparticles as vehicles for antitumour drugs

In this study, a new alternative of ionic crosslinked nanoparticles (NPs) based on chitosan (C) and bovine serum albumin (A; BSA) was evaluated as drug delivery system for antitumour compounds (doxorubicin hydrochloride as a model). The different responses to the pH of the medium were determined by the electrostatic interactions induced by each polymeric combination (C50/A50; C80/A20; C20/A80). NPs revealed a nanoscale size (167-392 nm) and a positive net charge (12-26 mV), modulated by doxorubicin (DOX) loading. Drug loading capacity was higher than 5.2 ± 1.8 μgDOX/mgNP (Encapsulation efficiency = 34%), and an initial burst release was followed by a sustained delivery. Cellular uptake assays confirmed the entry of NPs in three human tumor cells (MCF7, T47D and Hela), triggering antioxidant responses (superoxide dismutase, catalase, glutathione reductase and total glutathione content) in those cells. This was also consistent with the decreased in IC50 values observed after the incubation of these cells with C20/A80-DOX and C50/A50-DOX NPs (1.90-3.48 μg/mL) compared with free DOX (2.36-6.025 μg/mL). In vivo results suggested that the selected proportions of chitosan-BSA created nonhemolytic and biocompatible stable NPs at the selected dose of 20 mg/kg. Despite the different formulations, this study demonstrated that these NPs could serve as safe drug carriers in further in vivo investigations.

Seaweed Polysaccharide-Based Nanoparticles: Preparation and Applications for Drug Delivery

In recent years, there have been major advances and increasing amounts of research on the utilization of natural polymeric materials as drug delivery vehicles due to their biocompatibility and biodegradability. Seaweed polysaccharides are abundant resources and have been extensively studied for several biological, biomedical, and functional food applications. The exploration of seaweed polysaccharides for drug delivery applications is still in its infancy. Alginate, carrageenan, fucoidan, ulvan, and laminarin are polysaccharides commonly isolated from seaweed. These natural polymers can be converted into nanoparticles (NPs) by different types of methods, such as ionic gelation, emulsion, and polyelectrolyte complexing. Ionic gelation and polyelectrolyte complexing are commonly employed by adding cationic molecules to these anionic polymers to produce NPs of a desired shape, size, and charge. In the present review, we have discussed the preparation of seaweed polysaccharide-based NPs using different types of methods as well as their usage as carriers for the delivery of various therapeutic molecules (e.g., proteins, peptides, anti-cancer drugs, and antibiotics). Seaweed polysaccharide-based NPs exhibit suitable particle size, high drug encapsulation, and sustained drug release with high biocompatibility, thereby demonstrating their high potential for safe and efficient drug delivery.

Cyclodextrin-based nanosponges: a versatile platform for cancer nanotherapeutics development

Nanosponges (NSs) are a new age branched cyclodextrin (CD) polymeric systems exhibiting tremendous potential in pharmaceutical, agro science, and biomedical applications. Over the past decade, different varieties of NS based on the type of CD and the crosslinker have been developed tailored for specific applications. NS technology has been instrumental in achieving solubilization, stabilization, sustained release, enhancement of activity, permeability enhancement, protein delivery, ocular delivery, stimuli sensitive drug release, enhancement of bioavailability, etc. There is a major explosion of research in the area of NS-aided cancer therapeutics. A wide of anticancer molecules both from a pharmacological and physicochemical perspective have been developed as NS formulations by several groups including ours. Our objective in this review is to capture a systematic and comprehensive snapshot of the state-of-the-art of NS-aided cancer therapeutics reported so far. This review will provide an ideal platform for both the formulation scientists working on new polymeric/drug development and cancer biologists/scientists to understand the current nanotechnologies in CD-based NS-aided cancer therapeutics. The scope of the review is limited to small molecules and CD-based NS. The review covers in detail the problems associated with anticancer small molecules, and the solution provided by CD-based NS specifically for camptothecin, curcumin, paclitaxel, tamoxifen, resveratrol, quercetin, oxygen-NS, temozolomide, doxorubicin, and 5-Fluorouracil. WIREs Nanomed Nanobiotechnol 2016, 8:579-601. doi: 10.1002/wnan.1384 For further resources related to this article, please visit the WIREs website.

A green and highly efficient sulfur functionalization of starch

An innovative green approach to achieve thiol functionalization of starch with a degree of substitution ≥ 2.

Biopolymer-based nanoparticles for drug/gene delivery and tissue engineering

There has been a great interest in application of nanoparticles as biomaterials for delivery of therapeutic molecules such as drugs and genes, and for tissue engineering. In particular, biopolymers are suitable materials as nanoparticles for clinical application due to their versatile traits, including biocompatibility, biodegradability and low immunogenicity. Biopolymers are polymers that are produced from living organisms, which are classified in three groups: polysaccharides, proteins and nucleic acids. It is important to control particle size, charge, morphology of surface and release rate of loaded molecules to use biopolymer-based nanoparticles as drug/gene delivery carriers. To obtain a nano-carrier for therapeutic purposes, a variety of materials and preparation process has been attempted. This review focuses on fabrication of biocompatible nanoparticles consisting of biopolymers such as protein (silk, collagen, gelatin, β-casein, zein and albumin), protein-mimicked polypeptides and polysaccharides (chitosan, alginate, pullulan, starch and heparin). The effects of the nature of the materials and the fabrication process on the characteristics of the nanoparticles are described. In addition, their application as delivery carriers of therapeutic drugs and genes and biomaterials for tissue engineering are also reviewed.

Preactivated thiomers: permeation enhancing properties

The study was aimed to prepare a series of poly(acrylic acid)-cysteine-2-mercaptonicotinic acid conjugates (preactivated thiomers) and to evaluate the influence of molecular mass or degree of preactivation with 2-mercaptonicotinic acid (2MNA) on their permeation enhancing properties. Preactivated thiomers with different molecular mass and different degree of preactivation were synthesized and categorized on the basis of their molecular mass and degree of preactivation as PAA₁₀₀-Cys-2MNA (h), PAA₂₅₀-Cys-2MNA (h), PAA₄₅₀-Cys-2MNA (h), PAA₄₅₀-Cys-2MNA (m) and PAA₄₅₀-Cys-2MNA (l). In vitro permeation studies, the permeation enhancement ability for preactivated thiomers was ranked as PAA₄₅₀-Cys-2MNA (h) > PAA₂₅₀-Cys-2MNA (h) > PAA₁₀₀-Cys-2MNA (h) on both Caco-2 cell monolayers and rat intestinal mucosa. Comparing the influence of degree of preactivation with 2MNA on permeation enhancement, the following order PAA₄₅₀-Cys-2MNA (h) > PAA₄₅₀-Cys-2MNA (m) ≈ PAA₄₅₀-Cys-2MNA (l) on Caco-2 cell monolayers and PAA₄₅₀-Cys-2MNA (m) > PAA₄₅₀-Cys-2MNA (h) > PAA₄₅₀-Cys-2MNA (l) on intestinal mucosa was observed. The P_app of sodium fluorescein was 5.08-fold improved on Caco-2 cell monolayers for PAA₄₅₀-Cys-2MNA (h) and 2.46-fold improved on intestinal mucosa for PAA₄₅₀-Cys-2MNA (m), respectively, in comparison to sodium fluorescein in buffer only. These results indicated that preactivated thiomers could be considered as a promising macromolecular permeation enhancing polymer for non-invasive drug administration.