Chitosan as excellent bio-macromolecule with myriad of anti-activities in biomedical applications - A review

The aim of the study is to explore the myriad of anti-activities of chitosan - deacylated derivative of chitin in biomedical applications. Chitosan consists of reactive residual amino groups, which can be modified chemically to obtain wide range of derivatives. These derivatives exhibit the controlled physicochemical characteristics, which in turn improve its functional properties. Such derivatives find numerous applications in the field of biomedical science, agriculture, tissue engineering, bone regeneration and environmental science. This study presents a comprehensive overview of the multifarious anti-activities of chitosan and its derivatives in the field of biomedical science including anti-microbial, antioxidant, anti-tumor, anti-HIV, anti-fungal, anti- inflammatory, anti-Alzheimer's, anti-hypertensive and anti-diabetic activity. It briefly details these anti-activities with respect to its mode of action, pharmacological effects and potential applications. It also presents the overview of current research exploring novel derivatives of chitosan and its anti- activities in the recent past. Finally, the review projects the prospective potential of chitosan and its derivatives and expects to encourage the readers to develop new drug delivery systems based on such chitosan derivatives and explore its applications in biomedical science for benefit of mankind.

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.

Colloidal Nanocarriers as Versatile Targeted Delivery Systems for Cervical Cancer

BACKGROUND

The second most common malignant cancer of the uterus is cervical cancer, which is present worldwide, has a rising death rate and is predominant in developing countries. Different classes of anticancer agents are used to treat cervical carcinoma. The use of these agents results in severe untoward side-effects, toxicity, and multidrug resistance (MDR) with higher chances of recurrence and spread beyond the pelvic region. Moreover, the resulting clinical outcome remains very poor even after surgical procedures and treatment with conventional chemotherapy. Because of the nonspecificity of their use, the agents wipe out both cancerous and normal tissues. Colloidal nano dispersions have now been focusing on site-specific delivery for cervical cancer, and there has been much advancement.

METHODS

This review aims to highlight the problems in the current treatment of cervical cancer and explore the potential of colloidal nanocarriers for selective delivery of anticancer drugs using available literature.

RESULTS

In this study, we surveyed the role and potential of different colloidal nanocarriers in cervical cancer, such as nanoemulsion, nanodispersions, polymeric nanoparticles, and metallic nanoparticles and photothermal and photodynamic therapy. We found significant advancement in colloidal nanocarrier-based cervical cancer treatment.

CONCLUSION

Cervical cancer-targeted treatment with colloidal nanocarriers would hopefully result in minimal toxic side effects, reduced dosage frequency, and lower MDR incidence and enhance the patient survival rates. The future direction of the study should be focused more on the regulatory barrier of nanocarriers based on clinical outcomes for cervical cancer targeting with cost-effective analysis.

Anti-Inflammatory Activity of Chitosan and 5-Amino Salicylic Acid Combinations in Experimental Colitis

Chitosan is used in various drug delivery approaches as a pharmaceutical excipient. Although its potential as an immunomodulatory agent has been reported, its use in this capacity has not been fully explored. The efficacy of chitosan as an active pharmacological agent, particularly in anti-inflammatory therapy in inflammatory bowel diseases (IBD), was investigated in this study. The potential impact of the molecular weight (MW) and degree of deacetylation (DD) of chitosan was investigated together with 5-amino salicylic acid (5-ASA) for its efficacy in a combination anti-inflammatory therapy in murine experimental colitis. Such a combination would potentially be developed into novel dual strategies whereby chitosan acts as a mucoadhesive excipient as well as provide an additional anti-inflammatory benefit. Chitosan grades with different MW and DD were administered intrarectally alone or in combination with 5-ASA to colitis mice for 3 days. Myeloperoxidase (MPO) and alkaline phosphatase (ALP) activity and tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β) and nuclear factor kappa-B (NF-κB) levels were assessed from the colon. Intrarectal treatment of colitis with 30 mg/kg chitosan alone and with 30 mg/kg 5-ASA for 3 days led to a significant decrease in MPO, ALP, TNF-α, IL-6, IL-1β and NF-κB in colitis mice compared to untreated mice. Surprisingly, the efficacy of chitosan as an anti-inflammatory polymer was relatively independent from its structural properties, namely DD and MW. However, combinations of chitosan with 5-ASA showed a significant pharmacological improvement, whereby the additive anti-inflammatory efficacy observed shows the possibility of finetuning chitosan by combining it with anti-inflammatory agents to optimize its anti-inflammatory potential.

Preparation of an oil suspension containing ondansetron hydrochloride as a sustained release parenteral formulation

Ondansetron hydrochloride (ODS) is a selective 5-hydroxytryptamine type 3 antagonist for nausea and emesis prevention in neoplastic patients. To reduce dosing frequency and side effects and improve patient compliance, a sustained release parenteral formulation of ODS was developed. Microparticles of methylcellulose (MC) and ODS were prepared using the spray-drying method and suspended in oils to form oil suspensions. The formulations were evaluated for residual moisture, drug content, size distribution, DSC, XRD, FTIR, SEM, drug release, and pharmacokinetic studies. The effects of polymers and oils on the drug release were evaluated. MC showed the most prominent sustained release effect among various polymers examined with the optimum MC/ODS ratio of 2:1 (w/w). The particle size of the produced microparticles was in the mean diameter of approximately 3 μm. Physicochemical characterization suggested that ODS existed in an amorphous matrix within the microparticles and interacted with MC via hydrogen bonds. Corn oil was selected as the appropriate oil for suspension due to the sustained release of ODS and the appropriate viscosity. The optimized sustained release formulation of ODS was the corn oil suspension of spray-dried microparticles containing MC and ODS (2:1, w/w). It showed an in vitro drug sustained release up to 120 h, while the oil suspension of ODS without any polymer released the drug within 2 h. Following subcutaneous administration in rats, the optimized formulation could prolong the drug release until 72 h with the enhanced bioavailability in comparison with the ODS solution. The oil suspension of spray-dried microparticles might be an efficient approach for prolongation of the drug effect in the management of nausea and emesis. Graphical abstract.

Synthesis, characterization and evaluation of deacetylated xanthan derivatives as new excipients in the formulation of chitosan-based polyelectrolytes for the sustained release of tramadol

This paper addressed the application of deacetylated xanthan (XGDS) and chitosan (CTS) as a mixture blend forming hydrophilic matrices for Tramadol (TD) sustained release tablets. XGDSs derivatives were obtained by alkaline treatment of xanthan gum (XG) with various degrees of deacetylation (DD). The obtained products were characterized in terms of structural, thermal and physicochemical properties. Different tablet formulations containing CTS/XGDSs were prepared by direct compression method and compared to CTS/XG tablets. Flow properties of powder mixtures and pharmaceutical characteristics were evaluated. The dissolution test of TD was realized under simulated gastric and intestinal conditions to achieve drug release more than 24 h. All developed tablets were found conforming to standard evaluation tests. It was shown that CTS/XGDSs matrices ensure a slower release of TD in comparison with CTS/XG based formulations. Meanwhile, increasing DD resulted in a decrease of drug release. In addition, TD release from XGDS matrices was faster at pH (6.8) than at acidic pH (1.2). The matrix tablets based on CTS/XGDS4 (DD = 98.08%) were selected as the best candidates compared to the other systems in prolonging drug release. The optimal formulation was found to release 99.99% of TD after 24 h following a non-Fickian type.

Chitosan and its derivatives as vehicles for drug delivery

Chitosan and its derivatives as vehicles for drug delivery can achieve the purpose of sustained release and controlled release for drugs, improve the stability of drugs, and reduce adverse drug reactions. So, the bioavailability of drugs can be enhanced. Therefore, chitosan and its derivatives have become a hotspot in the field of drug delivery. Their characteristics as drug delivery vectors were introduced, the types and applications were summarized. The development direction of chitosan and its derivatives in this field was also forecasted.

Chitosan Nanolayered Cisplatin-Loaded Lipid Nanoparticles for Enhanced Anticancer Efficacy in Cervical Cancer

In this study, cisplatin (CDDP)-loaded chitosan-coated solid lipid nanoparticles (SLN) was successfully formulated to treat HeLa cervical carcinoma. The formulation nanoparticles were nanosized and exhibited a controlled release of drug in physiological conditions. The blank nanoparticles exhibited an excellent biocompatibility profile indicating its suitability for cancer targeting. The incorporation of CDDP in SLN remarkably increased the cancer cell death as evident from the MTT assay. Importantly, CDDP-loaded chitosan-coated SLN (CChSLN) significantly (P < 0.05) decreased the viability of cancer cells even at low concentration. The higher cytotoxicity potential of CChSLN was attributed to the higher cellular uptake as well as the sustained drug release manner in comparison with CSLN. Consistent with the cytotoxicity assay, CChSLN showed the lowest IC50 value of 0.6125 μg/ml while CSLN presented 1.156 μg/ml. CChSLN showed a significantly higher apoptosis in cancer cells compared to that of CSLN and CDDP, which is attributed to the better internalization of nanocarriers and controlled release of anticancer drugs in the intracellular environment. Our findings suggest that this new formulation could be a promising alternative for the treatment of cervical cancers. These findings are encouraging us to continue our research, with a more extended investigation of cellular response in real time and in animal models.

Nanomedicine-based combination of gambogic acid and retinoic acid chlorochalcone for enhanced anticancer efficacy in osteosarcoma

In this study, gambogic acid (GA) and retinoic acid chlorochalcone (RACC) co-loaded glycol chitosan nanoparticle was successfully developed and studied for its therapeutic efficacy against osteosarcoma cancer cells. The GA/RACC loaded glycol chitosan nanoparticles (RGNP) was nanosized and exhibited a controlled release of drug in either pH 7.4 and pH 5.0. Owing to the strong positive charge on the RGNP surface, efficiency cellular uptake was observed in cancer cells. Moreover, a synergistic combination of GA and RACC were effectively suppressed the tumor growth progression. The half maximal inhibitory concentration (IC50) values in MG63 cells were 0.89μg/ml and 0.35μg/ml for GA and RGNP after 24h. The results clearly suggest the synergist effect of GA and RACC in effectively inhibiting the cancer cell proliferation. The RGNP as expected induced a remarkably higher apoptosis of cancer cells with ∼28%. Overall, combination of GA and RACC encapsulated in a nanocarrier could be an effective strategy to treat osteosarcoma. Future studies will focus on the in vivo evaluation of GA/RACC-loaded polymeric nanoparticles.

Polysaccharide-based micro/nanocarriers for oral colon-targeted drug delivery

Oral colon-targeted drug delivery has attracted many researchers because of its distinct advantages of increasing the bioavailability of the drug at the target site and reducing the side effects. Polysaccharides that are precisely activated by the physiological environment of the colon hold greater promise for colon targeting. Considerable research efforts have been directed towards developing polysaccharide-based micro/nanocarriers. Types of polysaccharides for colon targeting and in vitro/in vivo assessments of polysaccharide-based carriers for oral colon-targeted drug delivery are summarised. Polysaccharide-based microspheres have gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon (colon cancer, inflammatory bowel disease (IBD), amoebiasis and irritable bowel syndrome (IBS)), but also for it's potential for the delivery of anti-rheumatoid arthritis and anti-chronic stable angina drugs. Besides, Polysaccharide-based micro/nanocarriers such as microbeads, microcapsules, microparticles, nanoparticles, nanogels and nanospheres are also introduced in this review.

Preparation, Evaluation and Optimization of Multiparticulate System of Mebendazole for Colon Targeted Drug Delivery by Using Natural Polysaccharides

PURPOSE

A Multiparticulate system of Mebendazole was developed for colon targeted drug delivery by using natural polysaccharides like Chitosan and Sodium-alginate beads.

METHODS

Chitosan microspheres were formulated by using Emulsion crosslinking method using Glutaraldehyde as crosslinking agent. Sodium-alginate beads were formulated by using Calcium chloride as gelling agent. Optimization for Chitosan microspheres was carried out by using 2(3) full factorial design. 3(2) full factorial design was used for the optimization of Sodium-alginate beads. The formulated batches were evaluated for percentage yield, particle size measurement, flow properties, percent entrapment efficiency, Swelling studies. The formulations were subjected to Stability studies and In-vitro release study (with and without rat caecal content). Release kinetics data was subjected to different dissolution models.

RESULTS

The formulated batches showed acceptable particle size range as well as excellent flow properties. Entrapment efficiency for optimized batches of Chitosan microspheres and sodium alginate beads was found to be 74.18% and 88.48% respectively. In-vitro release of drug for the optimized batches was found to be increased in presence of rat caecal content. The best-fit models were koresmeyer-peppas for Chitosan microspheres and zero order for sodium-alginate beads.

CONCLUSION

Chitosan and Sodium-alginate was used successfully for the formulation of Colon targeted Multiparticulate system.

Preparation and Characterization of Genipin-Crosslinked Chitosan Microspheres for the Sustained Release of Salidroside

Chitosan microspheres (CsMs) that encapsulate salidroside (Sal) were prepared by the emulsion crosslinking method with naturally occurring genipin (Gp) and then examined for their in vitro release. Sal-loaded CsMs (Sal-CsMs) showed nearly spherical and smooth surfaces with internal voids. The particle size of Sal-CsMs ranged within 0.56–5.01 μm, and their encapsulation efficiency and loading capacity were beyond 77.58% and 23.29%, respectively. The stability of Sal improved after entrapment into the CsMs. The release rate of Sal from CsMs was initially rapid, followed by sustained release. The release behavior depended on the pH of the release medium. The main release mechanisms underlying the release procedure were anomalous behavior and Fickian diffusion. These results indicated that CsMs with a novel crosslinker of Gp was a potential carrier system for producing functional foods containing Sal.

Comparative evaluation of polymeric and waxy microspheres for combined colon delivery of ascorbic acid and ketoprofen

The goal of this work was to combine the ketoprofen anti-inflammatory effect with the ascorbic acid antioxidant properties for a more efficient treatment of colonic pathologies. With this aim, microspheres (MS) based on both waxy materials (ceresine, Precirol(®) and Compritol(®)) or hydrophilic biopolymers (pectine, alginate and chitosan) loaded with the two drugs were developed, physicochemically characterized and compared in terms of entrapment efficiency, in vitro release profiles, potential toxicity and drug permeation properties across the Caco-2 cell line. Waxy MS revealed an high encapsulation efficiency of ketoprofen but a not detectable entrapment of ascorbic acid, while polymeric MS showed a good entrapment efficiency of both drugs. All MS need a gastro-resistant coating, to avoid any premature release of the drugs. Ketoprofen release rate from polymeric matrices was clearly higher than from the waxy ones. In contrast, the ASC release rate was higher, due to its high hydro-solubility. Cytotoxicity studies revealed the safety of all the formulations. Transport studies showed that the ketoprofen apparent permeability increased, when formulated with the different MS. In conclusion, only polymeric MS enabled an efficient double encapsulation of both the hydrophilic and lipophilic drugs, and, in addition, presented higher drug release rate and stronger enhancer properties.

Chitosan as a pore former in coated beads for colon specific drug delivery of 5-ASA

A multiparticulate product for colon-specific delivery of a small molecule drug has been developed and characterized. Microcrystalline cellulose core beads containing 5-aminosalicylic acid produced by extrusion-spheronization were coated with chitosan and Aquacoat(®) ECD mixtures according to a factorial design. Coated beads were characterized in terms of drug release, shape, and friability. The optimum formulation was enteric coated and exposed to media simulating conditions in the stomach, small intestine, and colon. Release studies in simulated intestinal fluid revealed that the drug release rate from the coated beads, which were spherical and rugged, depended on the level of chitosan in the coat and the coat thickness. Enlarged pores observed on the surface of the coated beads exposed to the medium containing rat cecal and colonic enzymes are believed to have caused a significant enhancement of the drug release rate compared to the control exposed only to simulated gastric and intestinal fluids. The release mechanisms involved polymer relaxation and dissolved drug diffusion for simulated intestinal fluid and simulated colonic fluid, respectively. From the facilitated drug release in a colonic environment and the inhibition of drug release under gastric and intestinal conditions, it can be concluded that this multiparticulate system demonstrates the potential for colon-specific drug delivery.