Novel microbially triggered colon specific delivery system of 5-Fluorouracil: Statistical optimization, in vitro, in vivo, cytotoxic and stability assessment

Physicochemical, structural and functional properties of low methoxyl pectin‑iron (III) complex and its effect on rats with iron deficiency anemia

Iron deficiency anemia (IDA) is the most common nutritional disease worldwide. In this study, a low methoxyl pectin (LMP)‑iron(III) complex was prepared. The physicochemical and structural properties were characterized by HPSEC, HPIC, CV, FTIR, 1H NMR, XRD, SEM and CD. The results showed that iron increased the molecular weight of the LMP‑iron(III) from 11.50 ± 0.32 to 12.70 ± 0.45 kDa and improved its crystallinity. Moreover, the findings demonstrated that -OH and -COOH groups in LMP coordinate with Fe3+ to form β-FeOOH. The water-holding capacity, emulsion stability, and antioxidant activities of the LMP‑iron(III) were lower than those of LMP. Furthermore, the therapeutic effects of LMP‑iron(III) on IDA were investigated in rats. Following LMP‑iron(III) supplementation, compared with the model group, the administration of LMP‑iron(III) significantly increased the body weight, hemoglobin concentration, and serum iron concentration as well as decreased free erythrocyte protoporphyrin concentration. Therefore, the LMP‑iron(III) can potentially treat IDA in rats experiments, providing a theoretical basis for the development of a promising iron supplement.

Responsive nanosystems for targeted therapy of ulcerative colitis: Current practices and future perspectives

The pharmacological approach to treating gastrointestinal diseases is suffering from various challenges. Among such gastrointestinal diseases, ulcerative colitis manifests inflammation at the colon site specifically. Patients suffering from ulcerative colitis notably exhibit thin mucus layers that offer increased permeability for the attacking pathogens. In the majority of ulcerative colitis patients, the conventional treatment options fail in controlling the symptoms of the disease leading to distressing effects on the quality of life. Such a scenario is due to the failure of conventional therapies to target the loaded moiety into specific diseased sites in the colon. Targeted carriers are needed to address this issue and enhance the drug effects. Conventional nanocarriers are mostly readily cleared and have nonspecific targeting. To accumulate the desired concentration of the therapeutic candidates at the inflamed area of the colon, smart nanomaterials with responsive nature have been explored recently that include pH responsive, reactive oxygen species responsive (ROS), enzyme responsive and thermo - responsive smart nanocarrier systems. The formulation of such responsive smart nanocarriers from nanotechnology scaffolds has resulted in the selective release of therapeutic drugs, avoiding systemic absorption and limiting the undesired delivery of targeting drugs into healthy tissues. Recent advancements in the field of responsive nanocarrier systems have resulted in the fabrication of multi-responsive systems i.e. dual responsive nanocarriers and derivitization that has increased the biological tissues and smart nanocarrier's interaction. In addition, it has also led to efficient targeting and significant cellular uptake of the therapeutic moieties. Herein, we have highlighted the latest status of the responsive nanocarrier drug delivery system, its applications for on-demand delivery of drug candidates for ulcerative colitis, and the prospects are underpinned.

Recent developments in natural biopolymer based drug delivery systems

Targeted delivery of drug molecules to diseased sites is a great challenge in pharmaceutical and biomedical sciences. Fabrication of drug delivery systems (DDS) to target and/or diagnose sick cells is an effective means to achieve good therapeutic results along with a minimal toxicological impact on healthy cells. Biopolymers are becoming an important class of materials owing to their biodegradability, good compatibility, non-toxicity, non-immunogenicity, and long blood circulation time and high drug loading ratio for both macros as well as micro-sized drug molecules. This review summarizes the recent trends in biopolymer-based DDS, forecasting their broad future clinical applications. Cellulose chitosan, starch, silk fibroins, collagen, albumin, gelatin, alginate, agar, proteins and peptides have shown potential applications in DDS. A range of synthetic techniques have been reported to design the DDS and are discussed in the current study which is being successfully employed in ocular, dental, transdermal and intranasal delivery systems. Different formulations of DDS are also overviewed in this review article along with synthesis techniques employed for designing the DDS. The possibility of these biopolymer applications points to a new route for creating unique DDS with enhanced therapeutic qualities for scaling up creative formulations up to the clinical level.

Targeting efficacy and anticancer activity of polymeric nanoparticles of SN-38 on colon cancer cell lines

Background

Colorectal cancer is the third most prevailing cancer in the whole world. Chemotherapeutic agents which are used for treatment have severe side effects and also have unwanted exposure to healthy cells. In the present study, polymeric nanoparticles of SN-38 were prepared (using cationic and anionic polymers). They were optimized by Box Behnken design and characterized for its physicochemical properties and in vitro drug release. Optimized formulation (CsENP) was evaluated for its targeting efficacy by Gamma Scintigraphy studies on Swiss Albino mice and in vitro Cytotoxic assay against colon cancer cell line, viz. HT-29.

Results

The images of Whole body gamma scintigraphy imaging of Swiss Albino mice show that CsENP remained intact till 2 h and after that at 4 h imaging it started dispersing and releasing drug which continued till 20 h. In Organ distribution studies, no radioactivity was traced in heart from the formulation. Even in liver, spleen, kidney and lung trace radioactivity was seen after 6 h. In case of CsENP radioactivity was seen in small intestine after 2 h and maximum (87.8% radioactivity) is seen in colon and rectum area after 4 h. At equivalent concentrations, the in vitro cell viability of HT-29 cells after 72 h incubation time showed that CsENP have enhanced cytotoxicity.

Conclusions

The results obtained of Whole body gamma scintigraphy imaging and organ distribution of Swiss Albino mice show that CsENP is Colon targeting and was found to be effective against colon cancer cell lines.

Colon targeted dosage form of Capecitabine using folic acid anchored modified carbon nanotube: in vitro cytotoxicity, apoptosis and in vivo roentgenographic study

OBJECTIVE

Development of dosage form comprising of Capecitabine loaded carbon nanotubes for its targeted delivery to the colon.

METHOD

Single walled carbon nanotubes (SWCNT) were functionalized by -COOH and Chitosan along with Folic acid. Capecitabine was loaded in these SWCNT's, and the system was analyzed by FTIR, SEM and Raman spectroscopy. Percent drug loading was assessed and the cytotoxicity (COLO320DM and HT29) was verified by using MTT and SRB assay. The apoptosis study was carried out by flowcytometry. The system was enclosed in an enteric coated capsule with pH sensitive polymers and characterized for invitro disintegration, dissolution and invivo roentgenographic studies.

RESULTS

FTIR, Raman and XRD studies indicated the confirmation of attachments, whereas SEM exhibited size range of 200-500 nm. Drug loading capacity was observed to be 94.63 ± 1.07%. Cytotoxicity studies of Capecitabine and FA-CHI-F-SWCNT-Capecitabine against COLO320DM by using MTT assay showed that FA-CHI-F-SWCNT- Capecitabine exhibited 86.45 ± 0.5788% inhibition whereas pure Capecitabine showed 50.52 ± 0.3106% inhibition. Against HT29, the % inhibition was observed to be 82.76 ± 0.4668% and 56.41 ± 0.2316% respectively for FA-CHI-F-SWCNT-Capecitabine and pure Capecitabine. In case of SRB assay of COLO320DM, the FA-CHI-F-SWCNT-Capecitabine exhibited 89.62 ± 0.4095% inhibition and Capecitabine showed 84.36 ± 0.2559% inhibition, whereas against HT29, FA-CHI-F-SWCNT-Capecitabine showed 81.36 ± 0.2958% inhibition and Capecitabine exhibited 90.62 ± 0.4196% inhibition.

CONCLUSION

FA-CHI-F-SWCNT loaded system revealed better cytotoxicity as compared with pure Capecitabine against two different cell lines. Invivo studies revealed that the prepared capsule formulation remained intact in the stomach thereby preventing drug release in the gastric milieu.

Recent Advances in Designing 5-Fluorouracil Delivery Systems: A Stepping Stone in the Safe Treatment of Colorectal Cancer

5-Fluorouracil (5-FU) has become one of the most widely employed antimetabolite chemotherapeutic agents in recent decades. It is considered a first line antineoplastic agent for the treatment of colorectal cancer. Unfortunately, chemotherapy with 5-FU has several limitations, including its short half-life, high cytotoxicity and low bioavailability. In order to overcome the drawbacks of 5-FU and enhance its therapeutic efficiency, many scientific groups have focused on designing a new delivery system to successfully deliver 5-FU to tumor sites. We provide a comprehensive review on different strategies to design effective delivery systems, including nanoformulations, drug-conjugate formulations and other strategies for the delivery of 5-FU to colorectal cancer. Furthermore, co-delivery of 5-FU with other therapeutics is discussed. This review critically highlights the recent innovations in and literature on various types of carrier system for 5-FU.

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.

Preparation and evaluation of captopril loaded gastro-retentive zein based porous floating tablets

In this study, gastro-retentive porous floating tablets of captopril based on zein are reported using l-menthol as a porogen. Tablets were prepared by the direct compression method. Removing of l-menthol through sublimation process generated pores in tablets, which decreased the density to promote floating over gastric fluid. Prepared tablets showed no floating lag time and prolong total floating time (>24 h). Drug release was found dependent upon porosity of tablets, an increase in porosity of tablets resulted in increased drug release, so it can be tuned by varying concentration of l-menthol. In addition to floating and sustained release properties, porous tablets showed robust mechanical behavior in wet conditions, which can enable them to withstand real gastric environment stress. In vivo studies using New Zealand rabbits also confirmed the prolonged gastric retention (24 h) and plasma drug concentration-time profile showed sustained release of captopril with higher T_max and MRT as compared to marketed immediate-release tablets. Overall, it was concluded that effective gastric retention can be achieved using porous zein tablets using l-menthol as a porogen.

Stimuli-Responsive Polymeric Nanosystem for Colon Specific Drug Delivery

An ideal colon specific drug delivery system needs to perform multiple functions like greater bio availability, less toxicity and higher therapeutic efficacy, all of which require high degree of smartness. This article focuses on the overview of the stimuli-responsive polymers and various nanodrug delivery systems which have found applications in colon specific delivery of drugs as this system provide a link between therapeutic need and drug delivery. These polymers exhibit a non-linear response to a small stimulus leading to a macroscopic alteration in their structure/properties. Stimuli responsive polymers display a significant physio chemical change in response to small changes in their environment (temperature, pH, light etc.). Colonic drug delivery has gained increased importance in treating diseases like Crohn's disease, ulcerative colitis, colon cancer etc. The expansion in the development of polymers based system with greater flexibility, versatility and unexplored potential enables new opportunities for them in uplifting bio medicine. Applying the concepts of smartness in the context of clinically relevant therapeutic and diagnostic systems, it can prelude in a new era of 'smart' therapeutics that can improve the health care fields. In particular, due to its high sensitivity to the stimuli, this system has been identified as a sensible platform for releasing drug at suitable site and at appropriate time.

In vivo evaluation of targeted delivery of biological agents using barium sulfate

This study was aimed to monitor the transit through the intestine by X-ray imaging using barium sulfate (BS) as tracer. The in vitro features of monolithic tablets were correlated with their in vivo behavior in order to provide a tool for the development of targeted formulations containing macromolecular bioactive agents. The impact of BS on various matrices (neutral, ionic) was studied in simulated fluids using the disintegration time (DT) as main parameter. Dry tablets were characterized by spectroscopic methods (X-ray diffraction and Infra-Red) and scanning electron microscopy (SEM). The selected formulations were followed in a beagle dog model. The in vivo and in vitro DT of tablets formulated with BS were compared. Results: anionic excipients carboxymethylcellulose (CMC) and carboxymethylstarch (CMS) protected the active ingredient from the gastric acidity, ensuring its targeted delivery in the intestine. The SEM analysis, before and after transit in simulated fluids, showed that BS remained in the tablets allowing their good follow-up in vivo. The incorporation of 30% protein in tablets with 40% BS had no impact on their behavior. In conclusion, BS and X-ray imagery could be a good alternative to scintigraphy for development of targeted formulations containing high molecular weight bioactive agents.

In Vitro Methods to Study Colon Release: State of the Art and An Outlook on New Strategies for Better In-Vitro Biorelevant Release Media

The primary focus of this review is a discussion regarding in vitro media for colon release, but we also give a brief overview of colon delivery and the colon microbiota as a baseline for this discussion. The large intestine is colonized by a vast number of bacteria, approximately 1012 per gram of intestinal content. The microbial community in the colon is complex and there is still much that is unknown about its composition and the activity of the microbiome. However, it is evident that this complex microbiota will affect the release from oral formulations targeting the colon. This includes the release of active drug substances, food supplements, and live microorganisms, such as probiotic bacteria and bacteria used for microbiota transplantations. Currently, there are no standardized colon release media, but researchers employ in vitro models representing the colon ranging from reasonable simple systems with adjusted pH with or without key enzymes to the use of fecal samples. In this review, we present the pros and cons for different existing in vitro models. Furthermore, we summarize the current knowledge of the colonic microbiota composition which is of importance to the fermentation capacity of carbohydrates and suggest a strategy to choose bacteria for a new more standardized in vitro dissolution medium for the colon.

Pectin and Pectin-Based Composite Materials: Beyond Food Texture

Pectins are plant cell wall natural heteropolysaccharides composed mainly of α-1-4 d-galacturonic acid units, which may or may not be methyl esterified, possesses neutral sugars branching that harbor functional moieties. Physicochemical features as pH, temperature, ions concentration, and cosolute presence, affect directly the extraction yield and gelling capacity of pectins. The chemical and structural features of this polysaccharide enables its interaction with a wide range of molecules, a property that scientists profit from to form new composite matrices for target/controlled delivery of therapeutic molecules, genes or cells. Considered a prebiotic dietary fiber, pectins meetmany regulations easily, regarding health applications within the pharmaceutical industry as a raw material and as an agent for the prevention of cancer. Thus, this review lists many emergent pectin-based composite materials which will probably palliate the impact of obesity, diabetes and heart disease, aid to forestall actual epidemics, expand the ken of food additives and food products design.

Formulation and evaluation of pH-sensitive rutin nanospheres against colon carcinoma using HCT-116 cell line

The objective of this study was to target rutin, in a more solubilized form, to the colon aiming at treatment of colon carcinoma. pH sensitive nanospheres were prepared by the nanoprecipitation technique employing Eudragit S100. Different drug: polymer ratios as well as different concentrations of the stabilizer Poloxamer-188 were used. The developed rutin nanospheres exhibited entrapment efficiency ranging from 94.19% to 98.1%, with a zeta potential values <−20 mV. They were spherical in shape and their sizes were in the nanometric dimensions. The in vitro release study of nanospheres formulations revealed enhancement of aqueous solubility of rutin and indicated drug targeting to the colon. The selected formulations were stable after storage for 6 months at ambient room and refrigeration temperatures. In vitro cytotoxic study was conducted on human colon cancer (HCT-116) as well as normal human fibroblasts (BHK) cell lines, employing Sulphorhodamine-B assay. Rutin nanospheres showed significantly (P = .001) higher area under inhibition percentage curve, when compared to free drug, revealing more than 2-fold increase in rutin cytotoxic activity. These results reveal that Eudragit S100 nanospheres could be a potential drug delivery system to the colon with enhanced solubility and hence improved the cytotoxic activity of rutin.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning electron microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were jointly reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24 h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

In vitro and in vivo study of a colon-targeting pH-sensitive hydrocortisone sodium succinate hydrogel

The aim of this study was to prepare and characterize a novel pH-sensitive hydrocortisone sodium succinate loaded hydrogel (HSS-GEL) for specifically delivering HSS to the colon, and evaluate its targeting properties.

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.

Comprehensive review on additives of topical dosage forms for drug delivery

Skin is the largest organ of the human body and plays the most important role in protecting against pathogen and foreign matter. Three important modes such as topical, regional and transdermal are widely used for delivery of various dosage forms. Among these modes, the topical dosage forms are preferred because it provides local therapeutic activity when applied to the skin or mucous membranes. Additives or pharmaceutical excipients (non-drug component of dosage form) are used as inactive ingredients in dosage form or tools for structuring dosage forms. The main use of topical dosage form additives are controling the extent of absorption, maintaining the viscosity, improving the stability as well as organoleptic property and increasing the bulk of the formulation. The overall goal of this article is to provide the clinician with information related to the topical dosage form additives and their current major applications against various diseases.

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.

Design, development, and optimization of polymeric based-colonic drug delivery system of naproxen

The aim of present investigation deals with the development of time-dependent and pH sensitive press-coated tablets for colon specific drug delivery of naproxen. The core tablets were prepared by wet granulation method then press coated with hydroxypropyl cellulose (HPC) or Eudragit RSPO : RLPO mixture and further coated with Eudragit S-100 by dip immerse method. The in vitro drug release study was conducted in different dissolution media such as pH 1.2, 6.8, and 7.4 with or without rat caecal content to simulate GIT conditions. Surface morphology and cross-sectional view of the tablets were visualized by scanning electron microscopy (SEM). All prepared batches were in compliance with the pharmacopoeial standards. The tablets which are compression coated with HPC followed by Eudragit S-100 coated showed highest in vitro drug release of 98.10% in presence of rat caecal content. The SEM of tablets suggested that the number of pores got increased in pH 7.4 medium followed by dissolution of coating layer. The tablets coat erosion study suggested that the lag time depends upon the coating concentrations of polymers. A time-dependent hydrophilic polymer and pH sensitive polymer based press-coated tablets of naproxen were promising delivery for colon targeting.

Tabletted guar gum microspheres of piroxicam for targeted adjuvant therapy for colonic adenocarcinomas

BACKGROUND

In recent years, nonsteroidal anti-inflammatory drugs have been found to be cogent as an adjuvant therapeutic agent in mitigating colorectal cancer. Thus, this present investigation was aimed to formulate an oral, targeted tablet of piroxicam microspheres for sustained and targeted adjuvant therapy for colonic adenocarcinomas.

RESULTS

Crosslinked guar gum microspheres of piroxicam were directly compressed into matrix tablet and coated with Eudragit S100. The optimized tablet that displayed 0% release in simulated gastric fluid, 15% in simulated intestinal fluid and 97.1% in simulated colonic fluid underwent roentgenographic study in rabbits to check its safe transit to the colon. x-ray images revealed intactness of the tablet until it reached the colon where the tablet matrix eroded.

CONCLUSION

The designed, conceptual formulation emerged as potential carrier for targeted adjuvant therapy of piroxicam.