Colon-specific Drug Delivery System Research Articles

Colon-targeted 3D-Printed mesalamine tablets: Core-shell design and in vitro/ex-vivo evaluation

ObjectivesThe present study is intended to develop a shell-core tablet using a hot melt extrusion (HME)-based dual-nozzle fused deposition modeling (FDM) three-dimensional (3D) printing approach. The primary objective was to establish a sustained-release colonic drug delivery system and improve mesalamine's permeability by incorporating Vitamin E TPGS as a permeation enhancer. MethodThe study utilized Kollidon® SR for sustained release, L-100, and HPMC HME L100 for the tablet's protective shell. Six filament formulations were tested, and the mechanical properties of the shell filaments, including the three-point bending, Hooke's law, and stiffness, were assessed. Drug release profiles of the tablets were evaluated using the USP-II dissolution apparatus, and permeability characteristics were gauged using the non-everted intestinal sac method. Solutions containing 5% w/v mesalamine and 2.5% w/v Vitamin E TPGS were employed, with pure mesalamine as a control. ResultsOptimal filament ratios were identified as 50:50 for the core and 30:70 for Eudragit L-100 to HPMC HME L100 for the shell. The resulting tablets achieved a prolonged drug release of up to 24 h for the core. They ensured minimal drug release in the upper gastrointestinal tract (∼5% in the first 5 h), effectively targeting the colon. Incorporating Vitamin E TPGS led to a 3.6-fold increase in mesalamine absorption compared to the control, and the addition of Kollidon® SR notably improved the flow properties of Mesalamine powder. ConclusionIn conclusion, this innovative approach has the potential to achieve a colon-specific drug delivery system.

Preparation and in-vitro evaluation of single and bi-layered beeswax-based microparticles for colon-specific delivery of mesalamine

Beeswax is selected as a natural coating material for the development of new colon specific drug delivery systems charged by mesalamine. In a first step, beeswax microparticles are prepared using hot-melt process of microencapsulation where drug:beeswax ratio, stirring speed, emulsifier concentration and pH of external phase are varied for the optimization of the drug entrapment and microparticles? morphology. The effect of the nature of the emulsifier is also discussed by studying the hydrophilic?lipophilic balance (HLB) value. In a second step, to obtain delayed delivery systems, bi-layered microspheres are elaborated by the process of emulsion?solvent evaporation using ethylcellulose or cellulose acetate butyrate as outer enteric coating layer. All formulations are characterized by infrared spectroscopy, X-ray diffraction, scanning electron microscopy and optical microscopy. The drug release is established in simulated gastric, small bowel and colon liquids and the release mechanism is discussed by applying the Korsmeyer?Peppas model.

Comparison of 5-ASA layered or matrix pellets coated with a combination of ethylcellulose and eudragits L and s in the treatment of ulcerative colitis in rats

The aim of this study was to evaluate and optimize the combination of time and pH-dependent polymers as a single coating for the design of the colon-specific drug delivery system of 5-aminosalicylic acid (5-ASA) pellets. 5-ASA matrix pellets with a 70% drug load were prepared by the extrusion-spheronization method. The optimal coating formula which included Eudragit S (ES) + Eudragit L (EL) + Ethylcellulose (EC) was predicted for the targeted drug delivery to the colonic area by a 32 factorial design. The ratio of ES:EL:EC and coating level were considered as independent variables while the responses were the release of less than 10% of the drug within 2 h (Y1), the release of 60–70% within 10 h at pH 6.8 (Y2) and lag time of less than 1 h at pH 7.2 (Y3). Also, 5-ASA layered pellets were prepared by the powder layering of 5-ASA on nonpareils (0.4–0.6 mm) in a fluidized bed coater and then coated with the same optimum coating composition. The coated 5-ASA layered or matrix pellets were tested in a rat model of ulcerative colitis (UC) and compared with the commercial form of 5-ASA pellets (Pentasa®). The ratio of ES:EL:EC of 33:52:15 w/w at a coating level of 7% was discovered as the optimum coating for the delivery of 5-ASA matrix pellets to the colon. The coated 5-ASA pellets were spherical with uniform coating as shown by SEM and met all of our release criteria as predicted. In-vivo studies demonstrated that the optimum 5-ASA layered or matrix pellets had superior anti-inflammatory activities than Pentasa® in terms of colitis activity index (CAI), colon damage score (CDS), colon/body weight ratio and colon’s tissue enzymes of glutathione (GSH) and malondialdehyde (MDA). The optimum coating formulation showed a high potential for colonic delivery of 5-ASA layered or matrix pellets and triggered drug release based on pH and time.

A Review on Colon Targeted Drug Delivery System

Colon-specific drug delivery systems (CDDS) are advantageous for the treatment of a range of local diseases such as ulcerative colitis, Crohn’s disease, irritable bowel syndrome, chronic pancreatitis, and colonic cancer. Colon targeted drug delivery system can be utilized to deliver protein and peptide drugs as they that are known to degrade in the extreme gastric pH. These approaches involve the use of formulation components that interact with one or more aspects of gastrointestinal (GI) physiology, such as the variation in the pH along the GI tract, the occurrence of colonic microflora, and enzymes, to attain colon targeting. This article highlights the advantages, limitations and factors influencing colon-specific drug delivery. Further, the review gives information of various conventional, as well as relatively newer formulation approaches presently being utilized for the improvement of CDDS.

Porous Silica as Drug Carrier for Controlled Delivery of Sulfasalazine: The Effect of Alginate-N, O-Carboxymethyl Chitosan Gel Coating and Amine Functionalization.

The necessity of colon-specific drug delivery systems has been well recognized. Porous silica (PSi) coated with a pH-sensitive, biocompatible, and biodegradable polymer can be useful in colon delivery. In this study, porous silica was synthesized and sulfasalazine was loaded into it to investigate the release rate in a simulated intestinal media. The media was kept at 37°C and pH 6.8 and 7.4, and subjected to continuous ultrasonic waves to simulate body fluid flow. Aqueous alginate and N, O-Carboxymethyl chitosan (NOCC) solutions, with a distinct composition (3% W/V) in different ratios, were prepared and coated on pressed porous silica disks. Porous silica (PSi) was also functionalized by aminopropyltrimethoxysilane grafting and was studied as a potential carrier for the controlled drug release of sulfasalazine. The release was studied in simulated gastric and intestinal media and results show that no burst release occurred in both coated and functionalized samples and the swelling degree of coats at basic and neutral media decreased by the presence of alginate in the network. It is concluded that the coat with a 50:50 ratio can release the colon drugs in 24h at a suitable rate. It is also envisioned that functionalization was a factor boosting drug uptake, however, the release rate was lower in the functionalized samples. This study opens the gates to new ideas for the potential safe and localized delivery of sulfasalazine.

Perspectives of colon-specific drug delivery in the management of morning symptoms of rheumatoid arthritis.

Rheumatoid arthritis is a chronic condition that is characterized by joint pain and inflammation. It is an autoimmune disorder in which the body tissues are erroneously attacked by the immune system of the host itself. It has been evident that rheumatoid arthritis symptoms follow a 24h circadian rhythm and exhibit high thresholds of pain, functional disability, and stiffness predominantly early in the morning. Colon-specific drug delivery systems can be utilized in the formulations to be used in the treatment of rheumatoid arthritis. The colon-specific drug delivery system has shown promising results in the treatment of different diseases at the colonic site like Crohn's disease, ulcerative colitis, colon cancer, etc. The colon-specific drug delivery is capable of delivering the formulation at the predetermined location and predetermined time. The early morning symptoms of rheumatoid arthritis like pain and inflammation can be treated using the various approaches of the colon-specific drug delivery system because it will lead to patient compliance as the patient will not require administering the formulation immediately after waking up in the morning. This review also explains the immunological factors which may trigger rheumatoid arthritis in human beings. It further explores conventional approaches like pH-dependant, microorganisms-driven, pressure-controlled, and time-dependant formulations. By employing two or more conventional approaches given above the various novel approaches have been designed to eliminate the drawbacks of individual techniques.

Colon Targeting: A Novel Drug Delivery System

The oral route is considered to be the most preferred route for administration of drugs for systemic effect, but the oral route is not suitable to the administration of drug for lower gastrointestinal (GI) diseases, this happened due to their release at upper GI tract (stomach, small intestine), which further minimizes the accessibility of drugs at the lower GI tract. To overcome this difficulty, colon-specific drug delivery systems have been broadly analyzed during the last two decades. Colonic drug delivery has gained increased importance not just for the delivery of the drugs for the treatment of local diseases associated with the colon like Crohn’s disease, ulcerative colitis, etc. but also for the systemic delivery of proteins, therapeutic peptides, anti-asthmatic drugs, antihypertensive drugs, and anti-diabetic agents. This review article discusses, in brief, the introduction of the colon, factor affecting the colonic transition, colonic diseases and the novel and emerging technologies for colon targeting.

Encapsulation of Marjoram Phenolic Compounds Using Chitosan to Improve Its Colon Delivery.

In this study, chitosan particles were used to encapsulate marjoram phenolic compounds as colon-specific drug-delivery systems. The microparticles were prepared by ionic gelation and spray-drying techniques and varying amounts of polymer and extract, along with different method conditions. The spray drying of microparticles (0.75% low molecular weight chitosan dissolved in 0.4% of acetic acid) presented the best encapsulation efficiency (near 75%), with size ranges from 1.55 to 1.68 µm that allowed the encapsulation of 1.25-1.88 mg/mL of extract. Release studies of individual marjoram phenolic compounds at pH 2 and 7.4 showed that most of the compounds remained encapsulated in the microparticles. Only arbutin and vicenin II presented a high initial burst release. As the polarity of the compounds was reduced, their initial release decreased. In addition, after gastrointestinal digestion, most of marjoram phenolic compounds remained encapsulated. These results prove that chitosan microparticlescould protect the marjoram phenolic compounds during gastrointestinal digestion, specifically those related to anticancer activity, which enables their application as colon-specific delivery systems.

NATURAL BIODEGRADABLE CIPROFLOXACIN MICROSPHERES: OPTIMIZATION STUDY BY FACTORIAL DESIGN

Oral drug delivery is the most popular method of control and release of therapeutic agents for the management of diseases. The colon specific drug delivery systems are considered to attain targeted drug delivery to the large intestine specifically at colon. They provide local delivery for the treatment of colonic diseases like inflammatory bowel disease. The present investigation is based on response of percent drug release as dependent variable for the study at Y axis with two different variables-concentration of surfactant (X1) and stirring speed (X2). A 32 full factorial design was used for complete reading of blending of polymers. The effects of surfactant concentration and stirring speed were evaluated by different parameters as entrapment efficiency, particle size, surface characteristics, micromeritic properties, DSC study and in vitro drug release studies. The present investigation reveals that galactomannan gum containing microspheres are promising as a carrier for colon targeted delivery of ciprofloxacin.

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.

A brief review on colon-specific drug delivery system for targeting to colonic region

Drug delivery to the colonic region refers to the drug that should have to released in the colonic environment instead of released in the upper gastrointestinal tract. To reach the site-specificity of the local treatment of the colon such as amoebiasis, colorectal cancer, and inflammatory bowel disease the target-specific drug delivery played an important role. To the establishment of the target-specific drug delivery to the colon, the various approach that has been explored include pH-dependent polymer, time-dependent, and bacteria-dependent drug delivery approach. Nanotechnology has been gaining much more interest due to target specificity and enhancement of bioavailability and high loading capacity. In this review, oral nanoparticle formulation for colon targeting specifically inflammatory bowel disease and suitable drugs for useful treatment and future aspects of nanoparticle formulation with particular approaches to enhancement of drug stability in the gastric environment have been covered.

Fabrication and characterization of budesonide loaded colon-specific nanofiber drug delivery systems using anionic and cationic polymethacrylate polymers

Inflammatory bowel disease (IBD) is a chronic disease characterized by the inflammation of the gastrointestinal system (GIS). Electrospun nanofibers are commonly used in pharmaceutical technology due to many advantages such as high porosity, loading efficiency, large surface area, and stability. Budesonide is the first choice drug in the treatment of IBD and is used as a model drug. In this study, it was aimed to obtain controlled release nanofibers for colon targeting by using anionic, pH-sensitive Eudragit S100 (ES100) and cationic, time-dependent Eudragit RL100 (ERL100) polymers. The conductivity, surface tension, and viscosity of the polymer solutions were analysed before electrospinning process. After production, the surface morphology, drug release kinetics, water contact angle, swelling index, and mucoadhesion studies of nanofibers were evaluated. Drug release studies were carried out at pH 1.2, 6.8, and 7.4. The formulation containing ES100:ERL100 (95:5) showed the most suitable drug release as a colon-specific drug delivery system with a minor release at pH 1.2, 6.8, and major release at pH 7.4. As a result, electrospun nanofibers obtained by mixing anionic and cationic polymethacrylate polymers may be a promising alternative as a drug delivery system in the treatment of IBD and other intestinal diseases.

Enhancing stability and anti-inflammatory properties of curcumin in ulcerative colitis therapy using liposomes mediated colon-specific drug delivery system

Curcumin liposomes (CUR-LPs) was identified by evaluating morphology, appearance, zeta potential, particle diameter, and drug encapsulation efficiency. The results indicated that particle diameter, surface charge and polydispersity index (PDI) of curcumin (CUR)-loaded anionic liposomes were 167 nm, −34 mV and 0.09, respectively. CUR-LPs is high stable pseudo-pH-sensitive nanoparticles system which has a favorable stability in simulated gastric fluid and slower degradation rate allowing CUR sustained release for prolonged times in simulated intestinal fluid. Within 1 h, the CUR consumption was 21.82% in simulated gastric fluid (SGF) and 27.32% in simulated intestinal fluid (SIF), respectively. CUR-LPs could attenuate clinical symptoms including weight loss, diarrhea and fecal bleeding. Especially, it could also prevent dextran sulfate sodium salt (DSS)-inducedcolon tissue damage and colon shortening, and reduce the production of malondialdehyde (MDA), colonic myeloperoxidase (MPO), Interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in animal model. Our study illustrated that liposomes (LPs) was a potential carrier to develop the colon-specific drug delivery system incorporating CUR for treating ulcerative colitis.

Polycaprolactone/polyethylene-glycol capsules made by injection molding: A drug release modeling

Polycaprolactone (PCL)/Polyethylene-glycol (PEG) capsules are prepared by injection molding with the aim of producing Colon-specific Drug Delivery Systems (CDDS). PCL, being a gastroresistant polymer, is suitable for this kind of delivery; however, the release from PCL devices is too slow. For this reason, in this paper, different percentages of PEG (10, 20 and 30 w/w %) have been added to obtain blends able to modulate the release from PCL-based capsules. The drug release rate from PCL/PEG capsules increases with the PEG percentage; using PCL/PEG 70/30 w/w capsules, the drug release is suitable for CDDS. The experimental data have been modelled, accounting for three steps: the penetration of the release medium into the capsule, the drug dissolution in the release medium, and the drug migration from the capsule to the medium. The model accurately describes the data, showing a mass transfer coefficient strongly dependent on the PEG percentage.

Fabrication and Characterization of Non-spherical Polymeric Particles

The particle shape is a key factor influencing drug loading, drug release, cellular interaction, cell uptake, and in vivo distribution of micro- and nanoparticles. The purpose of the study was to develop a preliminary proof of concept about the fabrication of non-spherical particles from spherical nanoparticles by simple film stretching method. The spherical Eudragit® S100 NPs was optimised with various parameters including, the concentration of the polymer, concentration of the surfactants, organic-aqueous phase ratio, and the speed of homogenization. Then, spherical NP-embedded polyvinyl alcohol (PVA) films were stretched to produce non-spherical particles. Finally, the resulting particle size and surface morphology of non-spherical Eudragit® S100 particles were analysed. Dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been utilised to analyse the size and morphology of particles, before and after film stretching. The resulting spherical NPs (< 150 nm) were successfully converted into monodispersed non-spherical, rod-like particles (< 500 nm) with precise shape control. The present study provided a simple and economic method for developing non-spherical Eudragit® S100 polymeric particles. These particles could be used as promising colon-specific drug delivery or diagnostic system.

Interpolymer Complexes Based on Eudragit&lt;sup&gt;®&lt;/sup&gt; EPO/Eudragit&lt;sup&gt;®&lt;/sup&gt; S100 as Carriers for Oral Controlled Drug Delivery Systems

Introduction. The possibility of obtaining IPC based on polyanions of various structures Eudragit ® , Carbopol ® , pectin, carrageenan and sodium alginate with oppositely charged polycations - Eudragit ® EPO, Eudragit ® RS/RL and chitosan, stabilized as already well-known by ionic bonds. It has been proven that interpolymer complexes with the participation of Eudragit ® copolymers could be also formatted by hydrogen bonds too as well. Prepared polycomplexes are promising carriers for drug delivery systems (DDS) to various parts of the gastrointestinal tract (GIT): the mouth (orodispersible and buccal DDS), stomach (gastroretentive DDS) and intestine (colon-specific DDS). Aim. Study of interpolymer complexes based on a pair of Eudragit ® EPO and Eudragit ® S100 copolymers obtained in a medium of various organic solvents (ethyl alcohol and a mixture of isopropanol-acetone (in a ratio of 60:40, v/v) from the point of view of their use in oral matrix systems for the delivery of active pharmaceutical ingredients. Materials and methods. The synthesis of interpolymer complexes based on Eudragit ® copolymers was carried out in organic solvents [ethyl alcohol or isopropanol-acetone mixture (in a ratio of 60:40, v/v)]. The structural features of the obtained IPCs were assessed by FTIR spectroscopy using a Nicolet iS5 instrument with a Smart iTR single ATR attachment (Thermo Scientific, USA) and differential scanning calorimetry with modulated temperature (mDSC) using a Discovery™ DSC instrument (TA Instruments, USA). The composition was determined using the method of elemental analysis on a Thermo Flash 2000 CHNS/O device (Thermo Fisher Scientific, UK). The swelling capacity of the obtained IPCs was evaluated in buffer media with pH values that mimic the pH of different parts of the gastrointestinal tract (GIT): 1.2; 5.8; 6.8 and 7.4. The release of theophylline (TEO) and diclofenac sodium (DS) was assessed on a ERWEKA DFZ II (ERWEKA GmbH, Germany) flow through cell apparatus in buffer media simulating the pH of various parts of the gastrointestinal tract for 7 hours. Results and discussion . All obtained IPCs are characterized by an excess of Eudragit ® S100 in their composition. The obtained IPCs are stabilized by a cooperative system of ionic and hydrogen bonds. DSC thermograms of IPC samples are characterized by the presence of a single glass transition temperature, which confirms the absence of impurities of free copolymers in their composition, while with an increase in the content of Eudragit ® S100 in the IPC composition, the glass transition temperature increases. The matrix based on IPC-1 disintegrated during the first 15 minutes of the experiment in a medium with pH 1.2, while matrices based on the rest of the IPC samples retain their shape for 7 hours and are characterized by pH-independent behavior. The release of TEO from polycomplex matrices is diffusion-controlled and occurs in accordance with Fick's law (IPC-2, IPC-4, and IPC-6) or can be characterized as «abnormal transport» (IPC-1, IPC-3 and IPC- 5), and also depends on the swelling capacity of the matrix. In contrast, the release of DS is dependent on surface erosion of the matrix, which is consistent with the Super Case II transport mechanism. Conclusion. The resulting interpolymer complexes Eudragit ® EPO/Eudragit ® S100 are promising carriers in matrix oral systems for the controlled delivery of active pharmaceutical ingredients, providing a prolonged release of BCS class I substances, depending on the diffusion rate from the swollen matrix, and a delayed release of BCS class II substances, controlled by surface processes erosion of the matrix.

A novel and simple oral colon-specific drug delivery system based on the pectin/modified nano-carbon sphere nanocomposite gel films

The 3-aminopropyltriethoxysilane modified nano-carbon sphere (MNCS) was added into pectin-Ca2+ film to improve the controlled release properties of the pectin-based oral colon-specific drug delivery system (OCDDS). The FT-IR measurements indicated the successful modification of nano-carbon sphere via silylation reaction and the electrostatic interaction between the pectin molecules and MNCS in the composite film. The FE-SEM showed the pore structure when the MNCS was mingled with the pectin. The 5-fluorouracil (5-FU) was employed as the drug model and the controlled release properties of the corresponding OCDDSs were determined. The values of the encapsulation efficiency ranged from 30.1% to 52.6%. All composite film based OCDDSs presented higher encapsulation efficiency than single pectin-Ca2+ based OCDDS. The drug release studies emerged that almost all the OCDDSs from composite films presented better release properties than single pectin-Ca2+ based OCDDS. The sample C revealed best release performance with the cumulative release rate of 32.17%, 22.77% and 63.89% in the simulated gastric fluid, small intestinal fluid and colon fluid, respectively. In addition, the kinetics studies were performed to analyze the release data. The cytotoxicity assay indicated good biocompatibility of the composite carriers.

Optimization of Colon Specific Drug Delivery System for Ornidazole using Modified Gum

The present study aimed to optimize a colon-specific formulation of ornidazole for the treatment of Crohn's disease and intestinal amoebiasis. Firstly carboxymethyl xanthan gum was prepared from xanthan gum reacting with monochloroacetic acid in alkaline conditions using the Williamson synthesis method. Fourier transform infrared spectrophotometer (FTIR) spectroscopy confirmed the formation of carboxymethyl xanthan gum. The differential scanning calorimetry (DSC) revealed the crystalline nature of carboxymethyl xanthan gum. A 32 full factorial design was used for optimization. The independent variables employed were the amount of Carboxymethyl Xanthan gum and the amount of hydroxy propyl methyl cellulose (HPMC), each at three levels. Drug release studies were carried out in various media [pH 1.2, 7.4, and 6.8]. The optimized formulation consisting of Carboxymethyl Xanthan gum (66 %) and HPMC (22%) released a small fraction of drug at pH 1.2 and pH 7.4, whereas significant drug release was observed at pH 6.8. The results of the study established Carboxymethyl Xanthan gum compression coated tablet to be a promising system for the colon-specific delivery of ornidazole to treat active Crohn's disease and intestinal amoebiasis.

Significance of Ligand-Anchored Polymers for Drug Targeting in the Treatment of Colonic Disorders.

Treatment of a variety of bowel diseases like Crohn’s disease, ulcerative colitis, colonic cancers, colonic pathologies, and systemic delivery of drugs at the target sites can be done with the help of targeted drug delivery technique. Conventional colon specific drug delivery systems lack specificity and release significant amount of drug prior reaching the target site. Hence, efficient drug delivery system that ensures effective release of the drug at the colon is still a sought after research arena. Ligand anchored therapy is a strong and effective approach to execute drug delivery in selective target cells, for both, diagnostic, as well as therapeutic reasons. Compared to the regular drugs, such ligand anchored therapy provides added benefit of minimum toxicity and few side effects. Discovery of overexpressed receptors on diseased cells, as compared to healthy cells led to the emergence of active drug targeting. Further, drug resistance constitutes one of the major reasons of the failure of chemotherapy and presents a major obstacle for the effective treatment. The reason behind drug resistance is exposure of pathological cells/pathogens to sub-therapeutic levels of drugs due lack of specificity of therapeutics. Active targeting, specifically taken up by the target cells, can warrant exposure of pathological cells/pathogens to high drug load at the target and sparing non-target cells hence minimal damage to normal cells and least chance of drug resistance. Many ligands like antibodies, aptamers, peptides, folate, and transferrin have been discovered in the past few years. The design of nanocarriers can be incorporated with many different functions which enables functions like imaging and triggered intracellular drug release. The present review article focuses on advances in ligand anchored therapy and its significance on the progress of targeted nanocarriers. It will also establish novel concepts like multi-targeting and multi-functional nanocarriers for the treatment of colonic disorders.

Colon Targeted Drug Delivery: A Review on Novel Approaches

Both local and systemic delivery of drugs can take place in colon. There are day by day new developments in field of colon specific drug delivery system. Colonic drug delivery has gained importance for the delivery of the drugs for the treatment of local diseases associated with the colon like Crohn’s disease, ulcerative colitis, etc. It has also used for the systemic delivery of proteins, therapeutic peptides, anti-asthmatic drugs, antihypertensive drugs and anti-diabetic agents drugs. Thereby reducing the systemic side effects treatment can be made effective if the drugs can be targeted directly into the colon. A drug need to be protected from degradation to achieve successful colon targeted drug delivery, release and absorption in upper portion of the GI tract and then to be ensured controlled release in the proximal colon. pH-dependent systems, time-dependent systems, and microbial triggered systems are the usual methods for delivering the drug to the last part of Gastro Intestinal tract. Pressure controlled colonic delivery capsules, CODESTM, and the osmotic controlled drug delivery are the newer technologies namely which are having in vivo site specificity, and feasibility of manufacturing process. The merits and demerits, novel approaches in the colon targeted drug delivery, clinical evaluation techniques and some information on the marketed dosage forms are one focused on in this review. To overcome pervious method’s limitations new systems and technologies have been developed for colon targeting. Colon targeting still need more innovative work even tough it holds a great potential and there are new developments in field of colon specific drug delivery system day by day.