Colon-specific delivery of 5-fluorouracil from zinc pectinate pellets through in situ intracapsular ethylcellulose-pectin plug formation

Carbohydrate Polymer-Based Targeted Pharmaceutical Formulations for Colorectal Cancer: Systematic Review of the Literature

Colon cancer is the third most diagnosed cancer worldwide, followed by lung and breast cancer. Conventional treatment methods are associated with numerous side effects and compliance issues. Thus, colon targeted drug delivery has gained much attention due to its evident advantages. Although many technologies have been explored, the use of pH-sensitive polymers, especially biodegradable polymers, holds exceptional promise. This review aims to collate research articles concerning recent advances in this area. A systematic search using multiple databases (Google Scholar, EMBASE, PubMed, MEDLINE and Scopus) was carried out following the preferred reported items for systematic reviews and meta-analyses (PRISMA) guidelines with an aim to explore the use of pH-sensitive carbohydrate polymers in developing colon targeted pharmaceutical formulations. Following screening and quality assessment for eligibility, 42 studies were included, exploring either single or a combination of carbohydrate polymers to develop targeted formulations for colon cancer therapy. Pectin (11) is the most widely used of these biopolymers, followed by chitosan (09), alginate (09) and guar gum (08). This systematic review has successfully gathered experimental evidence highlighting the importance of employing carbohydrate polymers in developing targeting formulations to manage colon cancer.

Targeted Delivery Methods for Anticancer Drugs

Several drug-delivery systems have been reported on and often successfully applied in cancer therapy. Cell-targeted delivery can reduce the overall toxicity of cytotoxic drugs and increase their effectiveness and selectivity. Besides traditional liposomal and micellar formulations, various nanocarrier systems have recently become the focus of developmental interest. This review discusses the preparation and targeting techniques as well as the properties of several liposome-, micelle-, solid-lipid nanoparticle-, dendrimer-, gold-, and magnetic-nanoparticle-based delivery systems. Approaches for targeted drug delivery and systems for drug release under a range of stimuli are also discussed.

Cellulose Nanofibers Improve the Performance of Retrograded Starch/Pectin Microparticles for Colon-Specific Delivery of 5-ASA

Cellulose nanofibers (CNF) were employed as the nanoreinforcement of a retrograded starch/pectin (RS/P) excipient to optimize its colon-specific properties. Although starch retrogradation ranged from 32 to 73%, CNF addition discretely disfavored the RS yield. This result agrees with the finding that in situ CNF reduces the presence of the RS crystallinity pattern. A thermal analysis revealed that the contribution of pectin improves the thermal stability of the RS/CNF mixture. Through a complete factorial design, it was possible to optimize the spray-drying conditions to obtain powders with high yield (57%) and low moisture content (1.2%). The powders observed by Field Emission Gum Scanning Electron Microscopy (FEG-SEM) had 1–10 µm and a circular shape. The developed methodology allowed us to obtain 5-aminosalicilic acid-loaded microparticles with high encapsulation efficiency (16–98%) and drug loading (1.97–26.63%). The presence of CNF in RS/P samples was responsible for decreasing the burst effect of release in simulated gastric and duodenal media, allowing the greatest mass of drug to be targeted to the colon. Considering that spray-drying is a scalable process, widely used by the pharmaceutical industry, the results obtained indicate the potential of these microparticles as raw material for obtaining other dosage forms to deliver 5-ASA to the distal parts of gastrointestinal tract, affected by inflammatory bowel disease.

Current Film Coating Designs for Colon-Targeted Oral Delivery

Colon-targeted oral delivery has recently attracted a substantial number of studies on both systemic and local treatments. Among approaches for colonic delivery, film coatings have been demonstrated as effective elements of the drug delivery systems because they can integrate multiple release strategies, such as pH-controlled release, time-controlled release and enzyme-triggered release. Moreover, coating layer modulations, natural film materials and nanoparticle coatings have been vigorously investigated with promising applications. This review aims to describe the primary approaches for improving drug delivery to the colon in the last decade. The outstanding importance of current developments in film coatings will advance dosage form designs and lead to the development of efficient colon-targeted oral delivery systems.

Mechanical characterization of bio composite films as a novel drug carrier platform for sustained release of 5-fluorouracil for colon cancer: Methodological investigation

In this study, we employed Pectin (PC) as a matrix that is hybridized with three different nucleobase (NB) units (cytosine, thymine, uracil) to generate pectin-nucleobase(PC-NB) biocomposite films stabilized through bio-multiple hydrogen bonds (BMHBs) as drug carrier for anticancer 5-Fluorouracil (5-FU). Prepared biocomposite films were characterized by Fourier Transform Infra-red Spectroscopy (FTIR), X-ray Diffraction (XRD), Thermogravimmetry Analysis (TGA) and Scanning Electron Microscope (SEM). Mechanical and sorption properties were also evaluated. In vitro drug release performed in both acidic pH 1.2 (stomach pH) and alkaline pH 7.4 (intestinal pH) showed that incorporation of nucleobases into pectin significantly restricted release rate of 5-FU particularly under acidic condition (pH 1.2). Hemolysis assays demonstrated that PC-NB-5-FU biocomposite film drug carriers were hemocompatible. Confocal microscope analysis indicates facilitated cellular uptake of PC-NB-5-FU film in HT-29 colon cancer cell line, which in turn result in a higher potential of apoptosis. Confocal imaging of fluorescent live/dead cell indicators and MTT assay outcomes, both demonstrated significant decreases in cellular viability of PC-NB-5-FU biocomposite films. Collectively, our findings indicate that this PC-NB-5-FU biocomposite films can be conferred as a proficient formulation for targeted delivery of colon cancer drugs.

Bridging the Gap of Drug Delivery in Colon Cancer: The Role of Chitosan and Pectin Based Nanocarriers System

Colon cancer is one of the most prevalent diseases, and traditional chemotherapy has not been proven beneficial in its treatment. It ranks second in terms of mortality due to all cancers for all ages. Lack of selectivity and poor biodistribution are the biggest challenges in developing potential therapeutic agents for the treatment of colon cancer. Nanoparticles hold enormous prospects as an effective drug delivery system. The delivery systems employing the use of polymers, such as chitosan and pectin as carrier molecules, ensure the maximum absorption of the drug, reduce unwanted side effects and also offer protection to the therapeutic agent from quick clearance or degradation, thus allowing an increased amount of the drug to reach the target tissue or cells. In this systematic review of published literature, the author aimed to assess the role of chitosan and pectin as polymer-carriers in colon targeted delivery of drugs in colon cancer therapy. This review summarizes the various studies employing the use of chitosan and pectin in colon targeted drug delivery systems.

Pectin polymers for colon-targeted antitumor drug delivery

The use of chemotherapeutic drugs in the treatment of malignant tumors is always associated with the severe side effects negatively affecting all organs and systems in human body. One of the approaches for reduction of the toxic influence and enhancement of the antitumor drug administration efficiency is supposed to be the use of the biopolymer delivery systems. Pectins are considered the most promising components for colon targeted drug dosage forms as they are stable in the changing gastrointestinal media and easily degraded by pectinases produced by colonic microflora. A various range of the pectin-containing delivery systems were developed contributing higher concentration of the active drug molecules in particular site inside intestine and their lower blood level resulting in lowered risk of the severe side effects. This review discusses the various forms of the pectin-based materials such as hydrogels, tablets and pellets, films, microspheres, microsponges, nanoparticles, etc. as drug delivery device and attempted to report the vast literature available on pectin biopolymers in drug delivery applications.

Development and characterization of pellets for targeted delivery of 5-fluorouracil and phytic acid for treatment of colon cancer in Wistar rat

The present study was designed to investigate the therapeutic efficacy of metal chelator and anticancer drug in the treatment of colorectal cancer (CRC). Pellets containing Phytic acid, 5- Fluorouracil (5-FU), Microcrystalline cellulose (MCC) PH 101, Hydroxypropyl Methylcellulose (HPMC) and Barium sulfate were prepared by using extrusion spheronization technique. Prepared pellets were coated with Eudragit S100 to achieve colon-specific drug delivery. Pellets were characterized for various pharmaceutical and micromeritic attributes. The in vivo therapeutic efficacy comprising of both pharmacokinetic and pharmacodynamic parameters was determined in Ehrlich ascites carcinoma (EAC) induced cancer animal model. Phytic acid and 5-FU combinations seem to exert higher cytotoxic activity via increased reactive oxygen species (ROS) level by chelating manganese. Further pharmacokinetic studies reveled approximately 50% lower Cmax in the finished formulation, indicates lower systemic exposure to the drug. X-ray radiography ensures the localized delivery of the encapsulated drug. Histopathological studies indicated no significant local toxicity compared to the uncoated formulation. Results inferred that the proposed combination has superior anticancer activity with minimum systemic and local toxicity and it opens a new avenue in the treatment of colorectal cancer.

Formulation and development of di-dependent microparticulate system for colon-specific drug delivery

Colorectal cancer (CRC) is the third most common cancer globally and the second most common cause of cancer-related deaths. Site-specific delivery of drugs leads to an increase in the availability of drugs at the targeted region. The objective of the present investigation was to develop a dually functional microparticulate colon-targeted drug delivery system of meloxicam for potential application in the prophylaxis of colorectal cancer. Chitosan microspheres were prepared by using emulsification-chemical cross-linking technique. Formulation parameters studied include chitosan concentration, drug to polymer ratio, agitation speed, emulsifier concentration, quantity of cross-linking agent and time for cross-linking. In vitro evaluation of microspheres revealed premature release of drug in the upper part of gastrointestinal tract. Since coating of microspheres is difficult to accomplish (with reproducible results), they were compacted to tablets. Enteric coating of tableted microspheres was achieved using Eudragit® S100. In vitro evaluation and SEM studies depict that the microspheres remain intact during compression process. The developed system was further evaluated for in vivo pharmacokinetic and roentgenography studies. In vivo pharmacokinetic evaluation in rabbits reveal that the onset of drug absorption from the coated tableted microspheres (T _{lag time} = 4.67 ± 0.58 h) was significantly delayed compared to uncoated tableted microspheres. In vivo roentgenographic study revealed that the system remained intact, until it reaches to the colonic region (5 h). Thus, from the results of the study, it can be revealed that the developed system could serve as a potential tool for efficient delivery of drug to the colonic region.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Getting into the colon: approaches to target colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in the world and the second most common cause of cancer related deaths. Conventional treatment of CRC is comprised of drug (chemotherapeutic agents) administration by parenteral route, which delivers the drug to both normal as well as cancerous tissues, thus leading to numerous undesirable effects. Enormous research is going on worldwide for designing an alternative route of administration, among which oral colon-targeted drug delivery systems have gained immense attention amongst scientific community. Direct delivery of drugs at the site of action leads to an increase in the availability of drugs at the targeted region. This causes a reduction in the amount of drug required to exert same therapeutic effect, thus reducing the incidents of adverse effects. Various maneuvers (pH-dependent, time-dependent and microflora-activated systems) have been attempted by researchers for targeting drugs successfully to the colonic region by circumventing the upper part of gastrointestinal tract. This Editorial article aims to put forth an overview of the formulation technologies that have been developed for attaining colon specific drug delivery for the treatment of CRC.

Anti-cancer activities of pH- or heat-modified pectin

Despite enormous efforts that have been made in the search for novel drugs and treatments, cancer continues to be a major public health problem. Moreover, the emergence of resistance to cancer chemotherapy often prevents complete remission. Researchers have thus turned to natural products mainly from plant origin to circumvent resistance. Pectin and pH- or heat-modified pectin have demonstrated chemopreventive and antitumoral activities against some aggressive and recurrent cancers. The focus of this review is to describe how pectin and modified pectin display these activities and what are the possible underlying mechanisms. The failure of conventional chemotherapy to reduce mortality as well as serious side effects make natural products, such as pectin-derived products, ideal candidates for exerting synergism in combination with conventional anticancer drugs.