Effect of co-administration of probiotics with polysaccharide based colon targeted delivery systems to optimize site specific drug release

Colorectal Cancer: Disease Process, Current Treatment Options, and Future Perspectives

Colorectal cancer (CRC) is one of the deadliest malignancies in the US, ranking fourth after lung, prostate, and breast cancers, respectively, in general populations. It continues to be a menace, and the incidence has been projected to more than double by 2035, especially in underdeveloped countries. This review seeks to provide some insights into the disease progression, currently available treatment options and their challenges, and future perspectives. Searches were conducted in the PubMed search engine in the university's online library. The keywords were "Colorectal Cancer" AND "disease process" OR "disease mechanisms" OR "Current Treatment" OR "Prospects". Selection criteria were original articles published primarily during the period of 2013 through 2023. Abstracts, books and documents, and reviews/systematic reviews were filtered out. Of over 490 thousand articles returned, only about 800 met preliminary selection criteria, 200 were reviewed in detail, but 191 met final selection criteria. Fifty-one other articles were used due to cross-referencing. Although recently considered a disease of lifestyle, CRC incidence appears to be rising in countries with low, low-medium, and medium social demographic indices. CRC can affect all parts of the colon and rectum but is more fatal with poor disease outcomes when it is right-sided. The disease progression usually takes between 7-10 years and can be asymptomatic, making early detection and diagnosis difficult. The CRC tumor microenvironment is made up of different types of cells interacting with each other to promote the growth and proliferation of the tumor cells. Significant advancement has been made in the treatment of colorectal cancer. Notable approaches include surgery, chemotherapy, radiation therapy, and cryotherapy. Chemotherapy, including 5-fluorouracil, irinotecan, oxaliplatin, and leucovorin, plays a significant role in the management of CRC that has been diagnosed at advanced stages. Two classes of monoclonal antibody therapies have been approved by the FDA for the treatment of colorectal cancer: the vascular endothelial growth factor (VEGF) inhibitor, e.g., bevacizumab (Avastin®), and the epidermal growth factor receptor (EGFR) inhibitor, e.g., cetuximab (Erbitux®) and panitumumab (Verbitix®). However, many significant problems are still being experienced with these treatments, mainly off-target effects, toxic side effects, and the associated therapeutic failures of small molecular drugs and the rapid loss of efficacy of mAb therapies. Other novel delivery strategies continue to be investigated, including ligand-based targeting of CRC cells.

Progress in construction and release of natural polysaccharide-platinum nanomedicines: A review

Natural polysaccharides are natural biomaterials that have become candidate materials for nano-drug delivery systems due to their excellent biodegradability and biocompatibility. Platinum (Pt) drugs have been widely used in the clinical therapy for various solid tumors. However, their extensive systemic toxicity and the drug resistance acquired by cancer cells limit the applications of platinum drugs. Modern nanobiotechnology provides the possibility for targeted delivery of platinum drugs to the tumor site, thereby minimizing toxicity and optimizing the efficacies of the drugs. In recent years, numerous natural polysaccharide-platinum nanomedicine delivery carriers have been developed, such as nanomicelles, nanospheres, nanogels, etc. Herein, we provide an overview on the construction and drug release of natural polysaccharide-Pt nanomedicines in recent years. Current challenges and future prospectives in this field are also put forward. In general, combining with irradiation and tumor microenvironment provides a significant research direction for the construction of natural polysaccharide-platinum nanomedicines and the release of responsive drugs in the future.

Design and development of pH-responsive alginate-based nanogel carriers for etoposide delivery

Recently, pH-responsive nanogels are playing progressively important roles in cancer treatment. The present study focuses on designing and developing pH-responsive alginate-based nanogels to achieve a controlled release of etoposide (Et) while enhancing its hydrophilicity. Alginate (ALG) is grafted with 2-hydroxypropyl methacrylamide (HPMA) through a microwave-supported method, and the chemical structure of the graft copolymer (ALG-g-PHPMA) was verified by 1H/13C NMR and FTIR techniques. The ALG-g-PHPMA and anticancer drug-loaded ALG-g-PHPMA@Et nanogels were obtained using an emulsion method, and their structures were characterized through FTIR, TG/DSC, AFM/TEM, BET, and DLS analyses. The ALG-g-PHPMA nanogels demonstrated a good drug encapsulation efficiency (79.60 %), displaying a pH-dependent release profile and an in vitro accelerated release of Et compared to the ALG nanogels. Thermal and BET analyses revealed enhanced stability, surface area, and porosity volume of the alginate nanogels. The grafting of PHPMA chains onto alginate altered the surface topology of the ALG nanogels, resulting in lower surface roughness. Furthermore, cytotoxicity tests showed the high biocompatibility of the ALG-g-PHPMA copolymer and its nanogels. The ALG-g-PHPMA@Et nanogels exhibited a higher anticancer effect on lung cancer (H1299) cells than free etoposide. These results suggest that the ALG-g-PHPMA nanogels can be applied as a pH-dependent nanoplatform for delivering anticancer drugs.

Microbiota-sensitive drug delivery systems based on natural polysaccharides for colon targeting

Colon targeting is an ongoing challenge, particularly for the oral administration of biological drugs or local treatment of inflammatory bowel disease (IBD). In both cases, drugs are known to be sensitive to the harsh conditions of the upper gastrointestinal tract (GIT) and, thus, must be protected. Here, we provide an overview of recently developed colonic site-specific drug delivery systems based on microbiota sensitivity of natural polysaccharides. Polysaccharides act as a substrate for enzymes secreted by the microbiota located in the distal part of GIT. The dosage form is adapted to the pathophysiology of the patient and, thus, a combination of bacteria-sensitive and time-controlled release or pH-dependent systems can be used for delivery.

Exploring the Dose–Effect Relationship of Bifidobacterium longum in Relieving Loperamide Hydrochloride-Induced Constipation in Rats through Colon-Released Capsules

Constipation is a common disease affecting humans. Bifidobacterium longum is reportedly effective in relieving constipation. Current studies generally focus on the dose–response relationship of oral doses; however, the dose–effect relationship of B. longum in the colon, which is the primary site where B. longum exerts constipation-relieving effects, to treat constipation has not been studied. Herein, three strains of B. longum (FGSZY6M4, FJSWXJ10M2, and FSDJN6M3) were packaged in colon-released capsules to explore the dose–effect relationship in the colon. For each strain, three groups of capsules (104, 106, and 108 CFU/capsule, respectively) and one group of free probiotics (108 CFU/mL) were used to explore the colonic dose effect of B. longum. The results showed that the three strains of B. longum improved fecal water content and promoted intestinal motility by regulating gastrointestinal peptide (MTL, GAS, and VIP), aquaporin-3, and 5-hydroxytryptamine levels while promoting gastrointestinal motility and relieving constipation by regulating the intestinal flora composition of constipated rats and changing their metabolite content (short-chain fatty acids). Among the three free bacterial solution groups (108 CFU/mL), FGSZY6M4 was the most effective in relieving constipation caused by loperamide hydrochloride in rats. The optimal effective dose of each strain was 6M4 (104 CFU/day), 10M2 (106 CFU/day), and S3 (108 CFU/day) of the colon-released capsules. Therefore, for some effective strains, the dose of oral probiotics can be reduced by colon-released capsules, and constipation can be relieved without administering a great number of bacterial solutions. Therefore, investigating the most effective dose of B. longum at the colon site can help to improve the efficiency of relieving constipation.

Tablet formulation with dual control concept for efficient colonic drug delivery

Aim of this study was to develop a tablet formulation for targeted colonic drug release by implementing two control mechanisms: A pH-sensitive coating layer based on Eudragit® FS 30 D to prevent drug release in the upper gastrointestinal tract, combined with a matrix based on plant-derived polysaccharide xyloglucan to inhibit drug release after coating removal in the small intestine and to allow microbiome triggered drug release in the colon. In vitro dissolution tests simulated the passage through the entire gastrointestinal tract with a four-stage protocol, including microbial xyloglucanase addition in physiologically relevant concentrations as microbiome surrogate to the colonic dissolution medium. Matrix erosion was monitored in parallel to drug release by measurement of reducing sugar equivalents resulting from xyloglucan hydrolysis. Limited drug release in gastric and small intestinal test stages and predominant release in the colonic stage was achieved. The xyloglucan matrix controlled drug release after dissolution of the enteric coating through the formation of a gummy polysaccharide layer at the tablet surface. Matrix degradation was dependent on enzyme concentration in the colonic medium and significantly accelerated drug release resulting in erosion-controlled release process. Drug release at physiologically relevant enzyme concentration was completed within the bounds of colonic transit time. The dual control concept was applicable to two drug substances with different solubility, providing similar release rates in colonic environment containing xyloglucanase. Drug solubility mechanistically affected release, with diffusion of caffeine, but not of 5-ASA, contributing to the overall release rate out of the matrix tablet.

Advances in Polysaccharide-Based Oral Colon-Targeted Delivery Systems: The Journey So Far and the Road Ahead

Various colon-targeted oral delivery systems have been explored so far to treat colorectal diseases, including timed-release systems, prodrugs, pH-based polymer coatings, and microflora-triggered systems. Among them, the microbially triggered system has gained attention. Among various oral colon-targeted delivery systems discussed, the polysaccharide-based colon-targeted delivery system has been found to be quite promising as polysaccharides remain unaffected by gastric as well as upper intestine milieu and are only digested by colonic bacteria upon reaching the colon. The major bottleneck associated with this delivery is that non-suitability of this system during the diseased state due to decrease in bacterial count at that time. This causes the failure of delivery system to release the drug even at colonic site as the polysaccharide matrix/coat cannot be digested properly due to lack of bacteria. The co-administration of probiotics is reported to compensate for the bacterial loss besides facilitating site-specific release. However, this research is also limited at the preclinical level. Hence, efforts are required to make this technology scalable and clinically applicable. This article entails in detail various oral colon-targeted delivery systems prepared so far, as well as the limitations and benefits of polysaccharide-based oral colon-targeted delivery systems.

Study on a novel enzymatic colon-targeted particle of total saponins of Pulsatilla by mechanical grinding technology in a solvent free system

Oral colon-targeting preparation can achieve targeted drug release in the lesion site and have a great application prospect. In this study, we presented the principle of particle design in the field of materials science into the preparation of colon-targeting preparation. Enzymatic Pulsatilla saponins Colon-targeting composite Microparticles (EPCM) were prepared by mechanical grinding without any organic solvent. Firstly, Response Surface Methodology (RSM) designed by Box-Behnken was used to optimize the preparation process of EPCM, and the structure of EPCM was characterized. All-Atomic and Molecular Dynamics (AAMD) was used to calculate the compatibility between drugs and coating materials before and after release, so as to explain the principle of colon- targeted drug release in this method. Then, colon-targeting characteristics of EPCM in vitro and in vivo were investigated by experiments. Finally, the pharmacodynamics effects of this composite microparticles on Ulcerative Colitis (UC) induced by DSS in C57BL/6 mice were evaluated. The results demonstrated that the colon-targeting composite microparticles could be prepared by mechanical grinding based on particle design principle. The composite microparticles have appropriate colon-targeting drug release performance in vitro and in vivo, and have good anti-ulcerative colitis effect. This study provides a new idea for the preparation of oral colon-targeting preparation of Traditional Chinese medicine, and has evident reference value for the study of coating isolation and powder modification of traditional Chinese medicine for other purposes.

Self-nanoemulsifying composition containing curcumin, quercetin, Ganoderma lucidum extract powder and probiotics for effective treatment of type 2 diabetes mellitus in streptozotocin induced rats

Liquid self-nanoemulsifying drug delivery system (L-SNEDDS) of curcumin and quercetin were prepared by dissolving them in isotropic mixture of Labrafil M1944CS®, Capmul MCM®, Tween-80® and Transcutol P®. The prepared L-SNEDDS were solidified using Ganoderma lucidum extract, probiotics and Aerosil-200® using spray drying. These were further converted into pellets using extrusion-spheronization. The mean droplet size and zeta potential of L-SNEDDS were found to be 63.46 ± 2.12 nm and - 14.8 ± 3.11 mV while for solid SNEDDS pellets, these were 72.46 ± 2.16 nm and -38.7 ± 1.34 mV, respectively. The dissolution rate for curcumin and quercetin each was enhanced by 4.5 folds while permeability was enhanced by 5.28 folds (curcumin) and 3.35 folds (quercetin) when loaded into SNEDDS pellets. The Cmax for curcumin and quercetin containing SNEDDS pellets was found 532.34 ± 5.64 ng/mL and 4280 ± 65.67 ng/mL, respectively. This was 17.55 and 3.48 folds higher as compared to their naïve forms. About 50.23- and 5.57-folds increase in bioavailability was observed for curcumin and quercetin respectively, upon loading into SNEDDS pellets. SNEDDS pellets were found stable at accelerated storage conditions. The developed formulation was able to normalize the levels of blood glucose, lipids, antioxidant biomarkers, and tissue architecture of pancreas and liver in streptozotocin induced diabetic rats as compared to their naïve forms.

Combination therapy of vanillic acid and oxaliplatin co-loaded in polysaccharide based functionalized polymeric micelles could offer effective treatment for colon cancer: A hypothesis

Colon cancer is characterised by the persistent change in bowel habits due to the formation of polyps (cancerous) in the inner lining of the colon. Clinically, there are several anticancer drugs available to treat colon cancer. Oxaliplatin (third generation platinum drug) is widely prescribed anticancer drug due to its broad range anticancer properties and low toxicities over cisplatin and carboplatin. Currently, use of oxaliplatin as adjuvant chemotherapy represents a standard care for the treatment of advanced colon cancer. Despite this, its rapid degradation in systemic circulations upon administration, lack of tumor specificity, and low bioavailability limits its anticancer potential. On the other hand, vanillic acid (VA) has shown anticancer potential in colon cancer by targeting mTOR/Ras pathway, HIF-1α inhibition, NF-ĸB, and Nrf2 that regulate cell growth, cell survival, proliferation and adaptation to cancer microenvironment. Normal oral delivery of these two drugs offers non-specific drug release in gastrointestinal tract that leads to unwanted toxicity and very less amount of drug become available for colonic site. Therefore, loading of these two drugs in polysaccharide based functionalized polymeric micelles (FPMs) can offer selective targeting at colonic site and could offer better therapeutic efficacy at much lesser doses of drugs. Therefore, a new hypothesis has been proposed that the combination of vanillic acid with oxaliplatin co-loaded in FPMs could provide colon targeting ability with enhanced potency and safety profile by targeting multiple pathways than current adjuvant chemotherapies available in the market for the treatment of colon cancer.

Pectin based multi-particulate carriers for colon-specific delivery of therapeutic agents

In case of colon-specific delivery of therapeutic agents through oral route, microbial/enzyme-triggered release approach has several advantages over other approaches due to unique microbial ecosystem in the colon. Multiple-unit carriers have an edge over single-unit carriers for this purpose. Among different materials/polymers explored, pectin appears as a promising biopolymer to construct microbial-triggered colon-specific carriers. Pectin is specifically degraded by colonic enzymes but insusceptible to upper gastro-intestinal enzymes. In this article, utilization of pectin solely or in combination with other polymers and/or colonic-delivery approaches is critically discussed in detail in the context of multi-particulate systems. Several studies showed that pectin-based carriers can prevent the release of payload in the stomach but start to release in the intestine. Hence, pectin alone may construct delayed release formulation but may not be sufficient for effective colon-targeting. On the other hand, combination of pectin with other materials/polymers (e.g., chitosan and Eudragit® S-100) has demonstrated huge promise for colon-specific release of payload. Hence, smartly designed pectin-based multi-particulate carriers, especially in combination with other polymers and/or colon-targeting approaches (e.g., microbial-triggered + pH-triggered or microbial-triggered + pH-triggered + time-release or microbial-triggered + pH-triggered + pressure-based), can be successful colon-specific delivery systems. However, more clinical trials are necessary to bring this idea from bench to bedside.

Exploring role of polysaccharides present in Ganoderma lucidium extract powder and probiotics as solid carriers in development of liquisolid formulation loaded with quercetin: A novel study

Ganoderma lucidium extract powder (GLEP) contains various polysaccharides which are well known for their antioxidant and anti-inflammatory actions. Probiotics (PB) are well-established for providing a plethora of health benefits. Hence, use of mushroom polysaccharides and probiotics as carriers to solidify liquisolid formulation is anticipated to function as functional excipients i.e. as adsorbent that may provide therapeutic benefits. Quercetin (QUR) has been used as model lipophilic drug in this study. QUR loaded liquisolid compacts (LSCs) were formulated using Tween 80 as solvent. These were further solidified using a combination of PB and GLEP as carriers. Aerosil-200 (A-200) was used as coating agent. The formulation exhibited very good flow characteristics. Dissolution rate of raw QUR was found to be less than 10% in 60 min while in case of QUR loaded LSCs, more than 90% drug release was observed within 5 min. Absence of crystalline peaks of QUR in the DSC and PXRD reports of LSCs and their porous appearance in SEM micrographs indicate that QUR was successfully incorporated in the LSCs. The developed formulation was found to be stable on storage under accelerated stability conditions.

Gut microbiota-driven drug metabolism in inflammatory bowel disease

BACKGROUND AND AIMS

The gut microbiota plays an important role in the metabolization and modulation of several types of drugs. With this study we aimed to review the literature about microbial drug metabolism of medication prescribed in inflammatory bowel disease practice.

METHODS

A systematic literature search was performed in Embase and PubMed from inception to October 2019. The search was conducted with predefined MeSH/Emtree and text terms. All studies about drug metabolism by microbiota of medication prescribed in inflammatory bowel disease practice were eligible. A total of 1018 records were encountered and 89 articles were selected for full text reading.

RESULTS

Intestinal bacterial metabolism or modulation is of influence in four specific drugs used in inflammatory bowel disease (mesalazines, methotrexate, glucocorticoids and thioguanine). The gut microbiota cleaves the azo-bond of sulfasalazine, balsalazide and olsalazine and releases the active moiety 5-aminosalicylic acid. It has an impact on the metabolization and potentially on the response of methotrexate therapy. Especially thioguanine can be converted by intestinal bacteria into the pharmacological active 6-thioguanine nucleotides without the requirement of host metabolism. Glucocorticoid compounds can be prone to bacterial degradation.

CONCLUSION

The human intestinal microbiota can have a major impact on drug metabolism and efficacy of medication prescribed in inflammatory bowel disease practice. A better understanding of these interactions between microbiota and drugs is needed and should be an integral part of the drug development pathway of new inflammatory bowel disease medication.

Drug-gut microbiota interactions: implications for neuropharmacology

The fate and activity of drugs are frequently dictated not only by the host per se but also by the microorganisms present in the gastrointestinal tract. The gut microbiome is known to, both directly and indirectly, affect drug metabolism. More evidence now hints at the effects that drugs can have on the function and composition of the gut microbiome. Both microbiota-mediated alterations in drug metabolism and drug-mediated alterations in the gut microbiome can have beneficial or detrimental effects on the host. Greater insights into the mechanisms driving these reciprocal drug-gut microbiota interactions are needed to guide the development of microbiome-targeted dietary or pharmacological interventions, which may have the potential to enhance drug efficacy or reduce drug side effects. In this review, we explore the relationship between drugs and the gut microbiome, with a specific focus on potential mechanisms underpinning the drug-mediated alterations on the gut microbiome and the potential implications for psychoactive drugs. LINKED ARTICLES: This article is part of a themed section on When Pharmacology Meets the Microbiome: New Targets for Therapeutics? To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.24/issuetoc.

The role of gut microbiota in the modulation of drug action: a focus on some clinically significant issues

INTRODUCTION

A healthy gut microbiota is necessary for the normal operation of several body functions, including gastrointestinal sensitivity and motility, lipid and glucid metabolism, immune surveillance, and host behavior. In addition, intestinal bacteria contribute to determining the pharmacological properties of several drugs by producing different drug metabolizing enzymes. Areas covered: Four enzymatic processes are discussed: prodrug activation; drug inactivation; drug deconjugation; and hydrolysis of natural glycosides with further metabolism of released aglycones. For each of these processes, a literature search has been undertaken on certain paradigmatic examples that have significant clinical implications: aminosalicylates and anthranoid laxatives; digoxin; irinotecan and non-steroidal anti-inflammatory drugs (NSAIDs); rutin, diosmin, and baicalin. Expert commentary: The modulation of certain reactions catalyzed by gut bacterial enzymes may offer new opportunities to improve the clinical efficacy of drugs such as aminosalicylates, and natural glycosides by increasing their metabolic transformation, and of digoxin by reducing its inactivation, or to decrease the lower intestinal toxicity of irinotecan, and NSAIDs by inhibiting the hydrolytic cleavage of their conjugates. Randomized clinical trials are awaited to clarify whether new intervention strategies may modulate these processes and provide clinical benefits such as improved therapeutic outcomes and drug safety profiles.

Novel biorelevant dissolution medium as a prognostic tool for polysaccharide-based colon-targeted drug delivery system

To overcome the limitations of the conventionally used methods for evaluation of orally administered colon-targeted delivery systems, a novel dissolution method using probiotics has been recently reported. In the present study, universal suitability of this medium composed of five different probiotics is established. Different delivery systems - mini tablets, liquisolid compacts, and microspheres coated with different polysaccharides - were prepared and subjected to sequential dissolution testing in medium with and without microbiota. The results obtained from fluid thioglycollate medium (FTM)-based probiotic medium for all the polysaccharide-based formulations showed statistically similar dissolution profile to that in the rat and goat cecal content media. Hence, it can be concluded that the developed FTM-based probiotic medium, once established, may eliminate the need for further animal sacrifice in the dissolution testing of polysaccharide-based colon-targeted delivery system.