In vitro cytotoxicity and in vivo efficacy of 5-fluorouracil-loaded enteric-coated PEG-cross-linked chitosan microspheres in colorectal cancer therapy in rats

Preparation and sustained release of diatomite incorporated and Eudragit L100 coated hydroxypropyl cellulose/chitosan aerogel microspheres

The drug encapsulation efficiency, release rate and time, sustained release, and stimulus-response of carriers are very important for drug delivery. However, these always cannot obtained for the carrier with a single component. To improve the comprehensive performance of chitosan-based carriers for 5-Fu delivery, diatomite-incorporated hydroxypropyl cellulose/chitosan (DE/HPC/CS) composite aerogel microspheres were fabricated for the release of 5-fluorouracil (5-Fu), and the release performance was regulated with the content of diatomite, pH value, and external coating material. Firstly, the 5-Fu loaded DE/HPC/CS composite aerogel microspheres and Eudragit L100 coated microspheres were prepared with cross-linking followed by freeze-drying, and characterized by SEM, EDS, FTIR, XRD, DSC, TG, and swelling. The obtained aerogel microspheres have a diameter of about 0.5 mm, the weight percentage of F and Si elements on the surface are 0.55 % and 0.78 % respectively. The glass transition temperature increased from 179 °C to 181 °C and 185 °C with the incorporation of DE and coating of Eudragit, and the equilibrium swelling percentage of DE/HPC/CS (1.5:3:2) carriers are 101.52 %, 45.27 %, 67.32 % at pH 1.2, 5.0, 7.4, respectively. Then, the effect of DE content on the drug loading efficiency of DE/HPC/CS@5-Fu was investigated, with the increase of DE content, the highest encapsulation efficiency was 82.6 %. Finally, the release behavior of DE incorporated and Eudragit L100 Coated microspheres were investigated under different pH values, and evaluated with four kinetic models. The results revealed that the release rate of 5-Fu decreased with the increase of DE content, sustained release with extending time and pH-responsive were observed for the Eudragit-coated aerogel microspheres.

Use of Chitosan as a Precursor for Multiple Applications in Medicinal Chemistry: Recent Significant Contributions

Chitosan (CS) is a polymer made up of mainly deacetylated β-1,4 D-glucosamine units, which is part of a large group of D-glucosamine oligomers known as chitooligosaccharides, which can be obtained from chitin, most abundant natural polymer after cellulose and central component of the shrimp exoskeleton. It is known that it can be used for the development of materials, among which its use stands out in wastewater treatment (removal of metal ions, dyes, and as a membrane in purification processes), food industry (anti-cholesterol and fat, packaging material, preservative, and food additive), agriculture (seed and fertilizer coating, controlled release agrochemicals), pulp and paper industry (surface treatment, adhesive paper), cosmetics (body creams, lotions, etc.), in the engineering of tissues, wound healing, as excipients for drug administration, gels, membranes, nanofibers, beads, microparticles, nanoparticles, scaffolds, sponges, and diverse biological ones, specifically antibacterial and antifungal activities. This article reviews the main contributions published in the last ten years regarding the use and application of CS in medical chemistry. The applications exposed here involve regenerative medicine in the design of bioprocesses and tissue engineering, Pharmaceutical sciences to obtain biomaterials, polymers, biomedicine, and the use of nanomaterials and nanotechnology, toxicology, and Clinical Pharmaceuticals, emphasizing the perspectives and the direction that can take research in this area.

Non-uniformity in in vitro drug-induced cytotoxicity as evidenced by differences in IC50 values - implications and way forward

Cell lines have proven indispensable for in vitro experiments and their utility as experimental models range from understanding the fundamental cell functioning to drug discovery. One of the most common utility of cell lines is for in vitro drug testing. Drug testing involves determining the cytotoxic effects of the drugs and such a measurement is expressed as the IC₅₀ values of drugs. Although determination of IC₅₀ values of drugs on cell lines is one of the most common in vitro experimental approaches, a significant amount of variations can be observed in the results obtained from such studies. Although the variations in the IC₅₀ values of a drug on different cells lines can and should vary, the non-uniformity of such results reported from different studies using a particular drug on a specific cell line is a matter of concern. We present the IC₅₀ values of 5 most commonly used drugs 5-fluorouracil, bleomycin, cisplatin, doxorubicin and methotrexate obtained from several in vitro cell line-based studies. Some of the factors which contribute to the non-uniformity of the IC₅₀ values for a particular drug from different studies are discussed as three types of factors, the biological, non-biological and human factors. Also, ways in which such variations can be reduced to obtain universally common, reliable results are presented.

Colorectal cancer management: Strategies in drug delivery

INTRODUCTION

Colorectal cancer (CRC) is the third most common cancer leading to death worldwide following breast and lung cancer with the incidence rate of 10%. The treatment comprises of surgery, radiation, and ablation therapy depending upon the stage of cancer.

AREAS COVERED

The review focuses on various drug delivery strategies explored to circumvent the major constraints associated with the conventional drug delivery systems- poor bioavailability, intra- and inter individual variability, exposure of normal cells to antineoplastic agents, and presence of efflux pump. All these attributes impact the effective delivery of chemotherapeutic agents at the tumor site. The various target specific drug delivery systems developed for colorectal cancer include pH dependent, microbiologically triggered, time dependent, magnetically driven, pressure dependent, prodrug/polysaccharide based, osmotic and ligand mediated systems. This review enumerates novel target specific approaches developed and investigated for potential utility in CRC therapeutics.

EXPERT OPINION

The limitations of conventional delivery systems can be overcome by development of colon-specific targeted drug delivery systems that overcome the obstacles of nonspecific biodistribution, drug resistance and unwanted adverse effects of conventional drug delivery systems. In addition, nanotechnology approaches help to increase drug solubility, bioavailability, reduce side effects and provide superior drug response in CRC.

Insight into the Loading Properties of Na+ Green-Functionalized Clinoptilolite as a Potential Carrier for the 5-Fluorouracil Drug, its Release Kinetics, and Cytotoxicity

Herein, natural zeolite (clinoptilolite) was functionalized by Na⁺ ions (G.Na⁺/Clino) utilizing a green tea extract prepared by a green production method as a potential carrier for the 5-fluorouracil (5-Fu) drug with enhanced physicochemical behaviors. The G.Na⁺/Clino-modified product showed enhanced surface area (312 m²/g) and ion-exchange capacity (387 mequiv/100 g). The loading studies reflect high and controlled loading properties of G.Na⁺/Clino with an actual loading capacity of 291 and 462 mg/g, respectively. The loading reactions of 5-Fu into G.Na⁺/Clino were of pseudo-second-order kinetics and exhibited Langmuir isotherm properties. This suggested a monolayer and homogeneous loading process by chemical complexation and ion-exchange mechanisms with a Gaussian energy value of 10.47 kJ/mol. Additionally, these reactions were of endothermic and spontaneous nature based on the determined thermodynamic parameters. The release studies demonstrated the 5-Fu release profile for about 150 h at pH 1.2 and for 80 h at pH 7.4. The release reactions had non-Fickian transport properties and were controlled by both erosion and diffusion mechanisms, considering the release kinetic findings and the values of the diffusion exponent (0.42 at pH 1.2 and 0.37 at pH 7.4). The composite showed remarkable biocompatibility based on the measured cell viability and a cytotoxic effect on normal colorectal cells (CCD-18Co). Additionally, the application of G.Na⁺/Clino as an inorganic carrier for the 5-Fu drug prompted the cytotoxic effect of the drug on colon cancer cell treatment (HCT-116).

Analytical and bioanalytical HPLC method for simultaneous estimation of 5-fluorouracil and sonidegib

Aim: To develop a new sensitive RP-HPLC method for simultaneous estimation of 5-fluorouracil (5-FU) and sonidegib (SDG). Materials & methods: Analytical and bioanalytical methods for simultaneous quantification of 5-FU and SDG in bulk, nanoformulations and in rat plasma were developed and validated using a gradient elution technique. Results: Separation of the analytes was effected on a Luna^® C18 LC column using a mobile mixture comprising acetonitrile and acidified water. 5-FU and SDG were extracted from plasma matrix using liquid-liquid extraction. The applicability of the method was verified through single-dose oral pharmacokinetic study in Wistar rats. Conclusion: The developed methods allow a specific, sensitive and steady analytical procedure for the simultaneous estimation of 5-FU and SDG in nanoformulations and biological matrix.

Targeted combined therapy in 2D and 3D cultured MCF-7 cells using metformin and erlotinib-loaded mesoporous silica magnetic nanoparticles

AIM

This research aims to develop potential therapeutic nanostructures (NSs) encapsulating metformin (MET) and erlotinib (ER) for combinational therapy in breast cancer.

METHODS

The ER and MET, both were loaded on mesoporous silica magnetic nanoparticles conjugated with polyethylene glycol and methotrexate to achieve targeted NSs. The developed NSs were characterised using SEM, DLS, and FTIR. Afterward, MTT, Trypan blue, and DNA extraction assays were operated for biological evaluations in the 2D and 3D MCF-7 cells.

RESULTS

Physicochemical approaches indicated the mean diameter of 69.4 nm ± 9.5 (PDI = 0.64), and neutral charge (2 mv) for the developed NSs. MET and ER-loaded NSs exhibited 62.56% ± 4.41 and 67.73% ± 3.03 drug release amount in pH = 5.4, respectively. MTT assay revealed that ER- and MET-loaded NSs had less metabolic activity (≈ 20%) in comparison with non-targeted NSs.

CONCLUSION

Overall, our combined ER and MET-loaded targeted NSs result in a synergistic inhibitory impact on MCF-7 cells.

Formulation, Characterisation and In vitro Cytotoxic Effect of Lens culinaris Medikus Seeds Extract Loaded Chitosan Microspheres

OBJECTIVE

The aim of present study was to formulate chitosan microspheres loaded with ethanolic extract of Lens culinaris Medikus (L.culinaris) seeds (ME) and to explore its anticancer potential against lung cancer (A549) cell line.

METHODS

Central composite design was applied to prepare and optimise the chitosan microspheres. The prepared microspheres were evaluated for its physicochemical characterisation, in vitro drug release and anti-cancer potential in vitro.

RESULTS

L.culinaris loaded chitosan microspheres were prepared successfully with suitable particle size, entrapment efficiency and drug release. The developed ME were spherical shaped with the particle size of 2.08 μm. The drug entrapment efficiency and cumulative drug release was found 1.58±0.02% and 81.95±0.35%, respectively. Differential scanning calorimetry studies revealed no interaction between drugs and polymers used. The cytotoxic effect of the optimised formulation revealed a significant response as compared to the ethanolic extract of L.culinaris seeds (IC₅₀: 22.56 μg/ml vs. 63.58 μg/ml), which was comparable to that of reference drug, doxorubicin (22 μg/ml). These observations demonstrate that the optimised microspheres are effective against lung cancer (A549) cells.

CONCLUSION

The significant cytotoxic response of the developed microspheres may be attributed due to its low particle size, high entrapment efficiency and prolonged drug release profile.

Crosslinking of Chitosan with Dialdehyde Chitosan as a New Approach for Biomedical Applications

Materials based on natural high molecular compounds are particularly interesting for biomedical applications. It is known that the cross-linking agent used for preparation of biomacromolecule-based materials is as important as used biopolymer. Therefore, natural cross-linkers containing reactive carbonyl groups are of great interest especially for modifying properties of natural polysaccharides. One of the most popular cross-linking agents is glutaraldehyde. Nevertheless, the unreacted particles can be released from the cross-linked material and cause cytotoxic effects. This can be eliminated when using a cross-linker based e.g., on polysaccharides. This article describes quick and efficient synthesis of dialdehyde chitosan (DACS) and its application for the preparation of chitosan films. Materials obtained with different amount of DACS were fully characterized in terms of structure and surface morphology. Thermal and mechanical properties as well as hydrophilic character were also examined. The results obtained were compared with the materials obtained by cross-linking chitosan with low molecular weight glutaraldehyde and high molecular weight cross-linking agent based on polysaccharide-dialdehyde starch. Toxicity of all obtained materials was tested using the Microtox® test. It has been shown that due to better mechanical, thermal and surface properties as well as lower toxicity, dialdehyde chitosan is a very promising crosslinking agent.

Preparation and evaluation of gastro-floating hollow adhesive microspheres of carbomer/ethyl cellulose encapsulating dipyridamole

Gastro-floating hollow adhesive microspheres of Carbomer/ethyl cellulose encapsulating dipyridamole were fabricated and evaluated in vitro and in vivo.