The quest for targeted delivery in colon cancer: mucoadhesive valdecoxib microspheres

3D printed tablets containing oxaliplatin loaded alginate nanoparticles for colon cancer targeted delivery. An in vitro/in vivo study

This study aimed to develop a colon-targeted tablet of oxaliplatin (OP) using the combination of nanotechnology and fused deposition modeling (FDM) 3D printing to improve its antitumor activity, tumor targetability, and safety profile. Eudragit L100-55 filament containing OP loaded alginate nanoparticles (OP-NPs) were fabricated using hot-melt extrusion method and printed by an FDM printer to 3D printed tablets with good uniformity in the drug content and selective release of OP in the colonic environment. The antitumor effect of 3D printed tablets containing OP-NPs in CT-26 tumor-bearing mice was evaluated compared to intravenous and oral administration of OP solution, and compressed tablets containing OP-NPs, which were prepared by direct compression method with the same formulation. The antitumor effect of 3D printed tablets containing OP-NPs was remarkable and comparable with intravenous OP solution (p ˃ 0.05) with a better safety profile, whereas compressed tablets did not show any significant antitumor effect, probably in terms of non-selective drug release in stomach and upper intestine environments. This study highlights the potential of the combination of nanotechnology and 3D printing in the preparation of colon-specific drug delivery systems of chemotherapeutic drugs with good antitumor activity, tumor targetability, and safety profile for colorectal cancer treatment.

Treating colon cancers with a non-conventional yet strategic approach: An overview of various nanoparticulate systems

Regardless of progress in therapy management which are developed for colon cancer (CC), it remains the third most common cause of mortality due to cancers around the world. Conventional medicines pose side effects due to untoward action on non-target cells. Their inability to deliver drugs to the affected regions of the colon locally, in a reproducible manner raises a concern towards the efficacy of therapy. In this regard, nanoparticles emerged as a promising drug delivery system due to their flexibility in designing, drug release modulation and cancer cell targeting. Not only are nanoparticles making their way into colon cancer research in the revolution of conventional onco-therapeutics, but they also offer promising scope in the development of colon cancer vaccines and theranostic tools. However, there are challenges with respect to drug delivery using nanoparticles, which may hamper the delivery of these novel carriers to the colon. The present review addresses recent advents in nanotechnology for colon-specific drug delivery (CDDS) which may help to overcome the existing challenges and intends to recognize futuristic potentials in the treatment of CC with CDDS.

Evaluation of the in vitro Antitumor Activity of Nanostructured Cyclotides in Polymers of Eudragit® L 100-55 and RS 30 D

Background:

Cancer is a major cause of mortality and morbidity and given the limitations of many current cancer drugs, there is great need to discover and develop novel treatments. An alternative to the conventional drug discovery path is to exploit new classes of natural compounds such as cyclotides. This peptide family is characterized by linked C- and N-termini and a structural fold called the cyclic cystine knot (CCK). The CCK fold is responsible for the exceptional enzymatic, chemical and thermal stability of cyclotides.

Methods:

In the present study, an alternative to traditional cancer treatments, involving new nanomaterials and nanocarriers allowing efficient cyclotide delivery, is proposed. Using the polymers Eudragit® L 100-55 and RS 30 D, the cyclotides kalata B2 and parigidin-br1 (PBR1) were nanocapsulated, and nanoparticles 91 nm and 188 nm in diameter, respectively, were produced.

Results:

An encapsulation rate of up to 95% was observed. In vitro bioassays showed that the nanostructured cyclotides were partially able to control the development of the colorectal adenocarcinoma cell line CACO2 and the breast cancer cell line MCF-7.

Conclusion:

Data reported herein indicate that nanoformulated cyclotides exhibit antitumor activity and sustained drug release. Thus, the system using Eudragit® nanocapsules seems to be efficient for cyclotide encapsulation and probably could be used to target specific tumors in future studies.

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.

Recent progresses in bioadhesive microspheres via transmucosal administration

Based on the advantages of adhesion preparations and the application status of microspheres (MSs) in mucous delivery, this paper primarily reviews the bioadhesive MSs via transmucosal administration routes, including the mucosa in alimentary tract and other lumens. Particularly, the detailed researches about of celladhesive MSs and some new-style bioadhesive MSs are mentioned. Furthermore, this review attempts to reveal the advances of bioadhesive MSs as cell-selective bioadhesion systems and the stimuli-responsive MSs as location-specific drug delivery systems. Although these MSs show powerful strength, some far-sighted ideas should be brought on agendas. In the future, mechanisms should be put under tight scrutiny and more attention should be focused on the excellent bioadhesive materials and the 'second generation mucoadhesives'. Meaningful clinical applications of these novel MSs are also of current concerns and need more detailed researches.

The Study of Different Approaches of Parecoxib Sodium Pretreatment on the Behavior of Rats with Neuropathic Pain

Our objective is to analyze and observe the different administration routes of parecoxib sodium pretreatment on the behavioral improvement of rats with neuropathic pain to provide the preclinical data of parecoxib sodium on neuropathic pain treatment. 30 SD rats were randomly divided into five groups, including model group, sham operation group, intrathecal injection group (IT group), intraperitoneal injection group (IP group), and perineural infiltration group (PI group). The rats in model group and three parecoxib sodium pretreatment groups received spinal nerve ligation (SNL). Heat pain test and 50 % paw mechanical withdrawal threshold test (50 % PMWT) were use to assess the responses after parecoxib sodium pretreatment. 50 % PMWT results of right foot in five groups had no statistical difference (P > 0.05); 50 % PMWT results of left and right feet in three parecoxib sodium pretreatment groups were obviously higher than SNL group at different time points, which was statistically different (P < 0.05); in comparison with three pretreatment groups, the data of left foot in IT group were obviously higher than PI group and IP group, and the comparison among three groups had significant difference (P < 0.05). However, the data of right foot had no significant difference among three groups (P > 0.05). Paw thermal withdrawal latency (PTWL) results of left and right feet in five groups had no significant difference before surgery (P > 0.05); after the establishment of neuropathic model, PTWL results in five groups were significantly decreased; however, PTWL results of left and right feet at 3 days after surgery in IT group were significantly higher than the two other pretreatment groups (P < 0.05); PTWL results of left and right feet at 7 and 14 days after surgery had no significant difference. Parecoxib sodium pretreatment can effectively improve the behaviors caused by neuropathic pain, and intrathecal injection is the most effective route of administration.

Silk fibroin nanoparticles constitute a vector for controlled release of resveratrol in an experimental model of inflammatory bowel disease in rats

Purpose

We aimed to evaluate the intestinal anti-inflammatory properties of silk fibroin nanoparticles, around 100 nm in size, when loaded with the stilbene compound resveratrol, in an experimental model of rat colitis.

Methods

Nanoparticles were loaded with resveratrol by adsorption. The biological effects of the resveratrol-loaded nanoparticles were tested both in vitro, in a cell culture of RAW 264.7 cells (mouse macrophages), and in vivo, in the trinitrobenzenesulfonic acid model of rat colitis, when administered intracolonically.

Results

The resveratrol liberation in 1× phosphate-buffered saline (PBS; pH 7.4) was characterized by fast liberation, reaching the solubility limit in 3 hours, which was maintained over a period of 80 hours. The in vitro assays revealed immunomodulatory properties exerted by these resveratrol-loaded nanoparticles since they promoted macrophage activity in basal conditions and inhibited this activity when stimulated with lipopolysaccharide. The in vivo experiments showed that after evaluation of the macroscopic symptoms, inflammatory markers, and intestinal barrier function, the fibroin nanoparticles loaded with resveratrol had a better effect than the single treatments, being similar to that produced by the glucocorticoid dexamethasone.

Conclusion

Silk fibroin nanoparticles constitute an attractive strategy for the controlled release of resveratrol, showing immunomodulatory properties and intestinal anti-inflammatory effects.

Effective inhibition of colon cancer cell growth with MgAl-layered double hydroxide (LDH) loaded 5-FU and PI3K/mTOR dual inhibitor BEZ-235 through apoptotic pathways

Colon cancer is the third most common cancer and the third largest cause of cancer-related death. Fluorouracil (5-FU) is the front-line chemotherapeutic agent for colon cancer. However, its response rate is less than 60%, even in combination with other chemotherapeutic agents. The side effects of 5-FU also limit its application. Nanoparticles have been used to deliver 5-FU, to increase its effectiveness and reduce side effects. Another common approach for colon cancer treatment is targeted therapy against the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway. A recently-invented inhibitor of this pathway, BEZ-235, has been tested in several clinical trials and has shown effectiveness and low side effects. Thus, it is a very promising drug for colon cancer treatment. The combination of these two drugs, especially nanoparticle-packed 5-FU and BEZ-235, has not been studied. In the present study, we demonstrated that nanoparticles of layered double hydroxide (LDH) loaded with 5-FU were more effective than a free drug at inhibiting colon cancer cell growth, and that a combination treatment with BEZ-235 further increased the sensitivity of colon cancer cells to the treatment of LDH-packed 5-FU (LDH-5-FU). BEZ-235 alone can decrease colon cancer HCT-116 cell viability to 46% of the control, and the addition of LDH-5-FU produced a greater effect, reducing cell survival to 8% of the control. Our data indicate that the combination therapy of nanodelivered 5-FU with a PI3K/Akt inhibitor, BEZ-235, may promise a more effective approach for colon cancer treatment.

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.

Alginate Particles as Platform for Drug Delivery by the Oral Route: State-of-the-Art

Pharmaceutical research and development aims to design products with ensured safety, quality, and efficacy to treat disease. To make the process more rational, coherent, efficient, and cost-effective, the field of Pharmaceutical Materials Science has emerged as the systematic study of the physicochemical properties and behavior of materials of pharmaceutical interest in relation to product performance. The oral route is the most patient preferred for drug administration. The presence of a mucus layer that covers the entire gastrointestinal tract has been exploited to expand the use of the oral route by developing a mucoadhesive drug delivery system that showed a prolonged residence time. Alginic acid and sodium and potassium alginates have emerged as one of the most extensively explored mucoadhesive biomaterials owing to very good cytocompatibility and biocompatibility, biodegradation, sol-gel transition properties, and chemical versatility that make possible further modifications to tailor their properties. The present review overviews the most relevant applications of alginate microparticles and nanoparticles for drug administration by the oral route and discusses the perspectives of this biomaterial in the future.

Reduced ABCB1 Expression and Activity in the Presence of Acrylic Copolymers

PURPOSE

P-glycoprotein (P-gp; ABCB1), an integral membrane protein in the apical surface of human intestinal epithelial cells, plays a crucial role in the intestinal transport and efflux leading to changes in the bioavailability of oral pharmaceutical compounds. This study was set to examine the potential effects of three Eudragits RL100, S100 and L100 on the intestinal epithelial membrane transport of rhodammine-123 (Rho-123), a substrate of P-gp using a monolayer of human colon cancer cell line (Caco-2).

METHODS

The least non-cytotoxic concentrations of the excipients were assessed in Caco-2 cells by the MTT assay. Then the transepithelial transport of Rho-123 across Caco-2 monolayers was determined with a fluorescence spectrophotometer. Besides, the expression of the P-gp in cells exposed to the polymers was demonstrated using Western-blotting analysis.

RESULTS

Treatment of cells with Eudragit RL100 and L100 led to a very slight change while Eudragit S100 showed 61% increase in Rho-123 accumulation (P<0.001) and also reduced transporter expression.

CONCLUSION

Our studies suggest that using proper concentrations of the Eudragit S100 in drug formulation would improve intestinal permeability and absorption of p-gp substrate 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.

Hyaluronan-cisplatin conjugate nanoparticles embedded in Eudragit S100-coated pectin/alginate microbeads for colon drug delivery

Hyaluronan–cisplatin conjugate nanoparticles (HCNPs) were chosen as colon-targeting drug-delivery carriers due to the observation that a variety of malignant tumors overexpress hyaluronan receptors. HCNPs were prepared by mixing cisplatin with a hyaluronan solution, followed by dialysis to remove trace elements. The cells treated with HCNPs showed significantly lower viability than those treated with cisplatin alone. HCNPs were entrapped in Eudragit S100-coated pectinate/alginate microbeads (PAMs) by using an electrospray method and a polyelectrolyte multilayer-coating technique in aqueous solution. The release profile of HCNPs from Eudragit S100-coated HCNP-PAMs was pH-dependent. The percentage of 24-hour drug release was approximately 25.1% and 39.7% in pH 1.2 and pH 4.5 media, respectively. However, the percentage of drug released quickly rose to 75.6% at pH 7.4. Moreover, the result of an in vivo nephrotoxicity study demonstrated that Eudragit S100-coated HCNP-PAMs treatment could mitigate the nephrotoxicity that resulted from cisplatin. From these results, it can be concluded that Eudragit S100-coated HCNP-PAMs are promising carriers for colonspecific drug delivery.

Evaluation of uptake and transport of cationic and anionic ultrasmall iron oxide nanoparticles by human colon cells

Nanoparticles (NPs) are in clinical use or under development for therapeutic imaging and drug delivery. However, relatively little information exists concerning the uptake and transport of NPs across human colon cell layers, or their potential to invade three-dimensional models of human colon cells that better mimic the tissue structures of normal and tumoral colon. In order to gain such information, the interactions of biocompatible ultrasmall superparamagnetic iron oxide nanoparticles (USPIO NPs) (iron oxide core 9–10 nm) coated with either cationic polyvinylamine (aminoPVA) or anionic oleic acid with human HT-29 and Caco-2 colon cells was determined. The uptake of the cationic USPIO NPs was much higher than the uptake of the anionic USPIO NPs. The intracellular localization of aminoPVA USPIO NPs was confirmed in HT-29 cells by transmission electron microscopy that detected the iron oxide core. AminoPVA USPIO NPs invaded three-dimensional spheroids of both HT-29 and Caco-2 cells, whereas oleic acid-coated USPIO NPs could only invade Caco-2 spheroids. Neither cationic aminoPVA USPIO NPs nor anionic oleic acid-coated USPIO NPs were transported at detectable levels across the tight CacoReady^™ intestinal barrier model or the more permeable mucus-secreting CacoGoblet^™ model.

Soluplus--solubilized citrated camptothecin--a potential drug delivery strategy in colon cancer

Camptothecin (CPT), a potent antitumor drug, exhibits poor aqueous solubility and rapid conversion from the pharmacologically active lactone form to inactive carboxylate form at physiological pH. Solid dispersion of CPT in Soluplus®, an amphiphilic polymeric solubilizer, was prepared to increase the aqueous solubility of CPT and the resultant solid dispersion along with citric acid was formulated as hard gelatin capsules that were subsequently coated with Eudragit S100 polymer for colonic delivery. FTIR spectrum of the solid dispersion confirmed the presence of CPT. PXRD and DSC revealed the semicrystalline nature of solid dispersion. The solubility of the drug was found to increase ~40 times in the presence of Soluplus and ~75 times in solid dispersion. The capsules showed no drug release in 0.01 N HCl but released 86.4% drug in lactone form in phosphate buffer (pH 7.4) and the result appears to be due to citric acid-induced lowering of pH of buffer from 7.4 to 6.0. Thus the presence of citric acid in the formulation led to stabilization of the drug in its pharmacologically active lactone form. Cytotoxicity studies conducted with the formulation of solid dispersion with citric acid, utilizing cell cytotoxicity test (MTT test) on Caco-2 cells, confirmed cytotoxic nature of the formulation.

Nebulized liposomal gadobenate dimeglumine contrast formulation for magnetic resonance imaging of larynx and trachea

Background

To develop a lipid-stabilized contrast formulation containing gadobenate dimeglumine for clear visualization of the mucosal surfaces of the larynx and trachea for early diagnosis of disease by magnetic resonance imaging.

Methods

The contrast formulation was prepared by loading gadobenate dimeglumine into egg phosphotidylcholine, cholesterol, and sterylamine nanoliposomes using the dehydration-rehydration method. The liposomal contrast formulation was ultrasonically nebulized, and the deposition and coating pattern on explanted pig laryngeal and tracheal segments was examined by inductively coupled plasma atomic emission spectroscopy. The sizes of the nebulized droplets were characterized by photon correlation spectroscopy. The contrast-enhanced mucosal surface images of the larynx and trachea were obtained in a 3.0T magnetic resonance scanner using a T1-weighted spectral presaturation inversion recovery sequence.

Results

Various cationic liposome formulations were compared for their stabilization effects on the droplets containing gadobenate dimeglumine. The liposomes composed of egg phosphotidylcholine, cholesterol, and sterylamine in a molar ratio of 1:1:1 were found to enable the most efficient nebulization and the resulting droplet sizes were narrowly distributed. They also resulted in the most even coating on the laryngeal and tracheal lumen surfaces and produced significant contrast enhancement along the mucosal surface. Such contrast enhancement could help clearer visualization of several disease states, such as intraluminal protrusions, submucosal nodules, and craters.

Conclusion

This lipid-stabilized magnetic resonance imaging contrast formulation may be useful for improving mucosal surface visualization and early diagnosis of disease originating in the mucosal surfaces of the larynx and trachea.

Preparation and characterization of a coacervate extended-release microparticulate delivery system for Lactobacillus rhamnosus

BACKGROUND

The purpose of this study was to develop a mucoadhesive coacervate microparticulate system to deliver viable Lactobacillus rhamnosus cells into the gut for an extended period of time while maintaining high numbers of viable cells within the formulation throughout its shelf-life and during gastrointestinal transit.

METHODS

Core coacervate mucoadhesive microparticles of L. rhamnosus were developed using several grades of hypromellose and were subsequently enteric-coated with hypromellose phthalate. Microparticles were evaluated for percent yield, entrapment efficiency, surface morphology, particle size, size distribution, zeta potential, flow properties, in vitro swelling, mucoadhesion properties, in vitro release profile and release kinetics, in vivo probiotic activity, and stability. The values for the kinetic constant and release exponent of model-dependent approaches, the difference factor, similarity factor, and Rescigno indices of model-independent approaches were determined for analyzing in vitro dissolution profiles.

RESULTS

Experimental microparticles of formulation batches were of spherical shape with percent yields of 41.24%-58.18%, entrapment efficiency 45.18%-64.16%, mean particle size 33.10-49.62 μm, and zeta potential around -11.5 mV, confirming adequate stability of L. rhamnosus at room temperature. The in vitro L. rhamnosus release profile follows zero-order kinetics and depends on the grade of hypromellose and the L. rhamnosus to hypromellose ratio.

CONCLUSION

Microparticles delivered L. rhamnosus in simulated intestinal conditions for an extended period, following zero-order kinetics, and exhibited appreciable mucoadhesion in simulated intestinal conditions.