pH-triggered surface charge-reversal nanoparticles alleviate experimental murine colitis via selective accumulation in inflamed colon regions.

In this study, we developed pH-triggered surface charge-reversal lipid nanoparticles (LNPs), loaded with budesonide, which could precisely deliver the drug to inflamed colon segments for the treatment of ulcerative colitis. Polyethyleneimine (PEI) was used to render LNPs cationic (PEI-LNPs), and Eudragit® S100 (ES) was coated on PEI-LNPs to obtain pH-triggered charge-reversal LNPs (ES-PEI-LNPs). ES coating avoided a burst drug release under acidic conditions mimicking the stomach and early small intestine environments and showed a sustained release in the colon. The surface charge of ES-PEI-LNPs switched from negative to positive under colonic conditions owing to pH-triggered removal of the ES coating. Bioimaging of the mouse gastrointestinal tract and confocal analysis of colon tissues revealed that ES-PEI-LNPs selectively accumulated in an inflamed colon. Furthermore, ES-PEI-LNPs mitigated experimental colitis in mice. These results suggest that the pH-triggered charge-reversal LNPs could be a promising drug carrier for ulcerative colitis therapy and other colon-targeted treatments.

Dithiocarbamate chitosan as a potential polymeric matrix for controlled drug release.

OBJECTIVE: To develop a polymer matrix for controlled release of drugs, chitosan, a linear aminopolysaccharide, was chemically modified to dithiocarbamate chitosan (DTCC) to afford a matrix where metal-drug complexes could be attached and released in a controlled manner depending on the binding nature between the drugs and the metals. MATERIALS AND METHODS: DTCC was treated with metal-tetracycline (Tc) complexes to prepare DTCC-Ca(II)-Tc, DTCC-Mg(II)-Tc, DTCC-Cu(II)-Tc and DTCC-Zn(II)-Tc. RESULTS: The binding amount of Tc was in the order of DTCC-Zn(II)-Tc ≈ DTCC-Mg(II)-Tc ≈ DTCC-Ca(II)-Tc > DTCC-Cu(II)-Tc. The biphasic binding profiles, where Tc binding increased initially and then decreased, were shown for DTCC-Cu(II)-Tc and DTCC-Zn(II)-Tc. In a flow method, Tc was released slowly from DTCC-metal-Tc complexes except for DTCC-Cu(II)-Tc compared with Tc release from DTCC-Tc. In parallel with the results of the release experiment, DTCC-metal-Tc complexes except for DTCC-Cu(II)-Tc presented a prolonged antibacterial activity in an antibacterial test. The antibacterial activity of DTCC-Ca(II)-, -Mg(II)- and -Zn(II)-Tc complexes lasted for 28-44 days, while free Tc and DTCC-Tc lasted for 7-12 days. DISCUSSION AND CONCLUSION: Taken together, our data suggest that DTCC could be used for a polymeric matrix for controlled release of drugs such as Tc, which possess functional groups for ionic and/or coordinate bond with metals.

Ionically bridged dexamethasone sodium phosphate-zinc-PLGA nanocomplex in alginate microgel for the local treatment of ulcerative colitis.

Colon-targeted oral drug delivery systems comprising nanoparticles and microparticles have emerged as promising tools for the treatment of ulcerative colitis (UC) because they minimize side effects and maximize the local drug concentration. Dexamethasone sodium phosphate (DSP) is a potent anti-inflammatory glucocorticoid used for the treatment of UC. However, it remains a rather short-term treatment option owing to its side effects. In the present study, we developed the alginate gel encapsulating ionically bridged DSP-zinc-poly(lactic-co-glycolic acid) (PLGA) nanocomplex (DZP-NCs-in-microgel) for the oral local treatment of UC. The successful encapsulation of DSP-zinc-PLGA nanocomplex (DZP-NCs) in alginate microgel was confirmed by SEM imaging. The prepared gel released DZP-NCs in the stimulated intestinal fluid and dampened the release of DSP in the upper gastrointestinal tract. Furthermore, DZP-NCs-in-microgel alleviated colonic inflammation in a mouse model of dextran sodium sulfate-induced colitis by relieving clinical symptoms and histological marks. Our results suggest a novel approach for the oral colon-targeted delivery of dexamethasone sodium phosphate for the treatment of UC.

Bacteria-Adhesive Nitric Oxide-Releasing Graphene Oxide Nanoparticles for MRPA-Infected Wound Healing Therapy.

A bacteria-infected wound can lead to being life-threatening and raises a great economic burden on the patient. Here, we developed polyethylenimine 1.8k (PEI1.8k) surface modified NO-releasing polyethylenimine 25k (PEI25k)-functionalized graphene oxide (GO) nanoparticles (GO-PEI25k/NO-PEI1.8k NPs) for enhanced antibacterial activity and infected wound healing via binding to the bacterial surface. In vitro antibacterial activity and in vivo wound healing efficacy in an infected wound model were evaluated compared with NO-releasing NPs (GO-PEI25k/NO NPs). Surface modification with PEI1.8k can enhance the ability of nanoparticles to adhere to bacteria. GO-PEI25k/NO-PEI1.8k NPs released NO in a sustained manner for 48 h and exhibited the highest bactericidal activity (99.99% killing) against methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Pseudomonas aeruginosa (MRPA) without cytotoxicity to L929 mouse fibroblast cells at 0.1 mg/mL. In the MRPA-infected wound model, GO-PEI25k/NO-PEI1.8k NPs showed 87% wound size reduction while GO-PEI25k/NO NPs showed 23% wound size reduction at 9 days postinjury. Masson trichrome and hematoxylin and eosin staining revealed that GO-PEI25k/NO-PEI1.8k NPs enhanced re-epithelialization and collagen deposition, which are comparable to healthy mouse skin tissue. GO-PEI25k/NO-PEI1.8k NPs hold promise as effective antibacterial and wound healing agents.

Oral delivery of natural active small molecules by polymeric nanoparticles for the treatment of inflammatory bowel diseases.

The incidence of inflammatory bowel disease (IBD) is rapidly rising throughout the world. Although tremendous efforts have been made, limited therapeutics are available for IBD management. Natural active small molecules (NASMs), which are a gift of nature to humanity, have been widely used in the prevention and alleviation of IBD; they have numerous advantageous features, including excellent biocompatibility, pharmacological activity, and mass production potential. Oral route is the most common and acceptable approach for drug administration, but the clinical application of NASMs in IBD treatment via oral route has been seriously restricted by their inherent limitations such as high hydrophobicity, instability, and poor bioavailability. With the development of nanotechnology, polymeric nanoparticles (NPs) have provided a promising platform that can efficiently encapsulate versatile NASMs, overcome multiple drug delivery barriers, and orally deliver the loaded NASMs to targeted tissues or cells while enhancing their stability and bioavailability. Thus, NPs can enhance the preventive and therapeutic effects of NASMs against IBD. Herein, we summarize the recent knowledge about polymeric matrix-based carriers, targeting ligands for drug delivery, and NASMs. We also discuss the current challenges and future developmental directions.

Tumor-Penetrable Nitric Oxide-Releasing Nanoparticles Potentiate Local Antimelanoma Therapy.

Although nitric oxide (NO) has been emerging as a novel local anticancer agent because of its potent cytotoxic effects and lack of off-target side effects, its clinical applications remain a challenge because of the short effective diffusion distance of NO that limits its anticancer activity. In this study, we synthesized albumin-coated poly(lactic-co-glycolic acid) (PLGA)-conjugated linear polyethylenimine diazeniumdiolate (LP/NO) nanoparticles (Alb-PLP/NO NPs) that possess tumor-penetrating and NO-releasing properties for an effective local treatment of melanoma. Sufficient NO-loading and prolonged NO-releasing characteristics of Alb-PLP/NO NPs were acquired through PLGA-conjugated LP/NO copolymer (PLP/NO) synthesis, followed by nanoparticle fabrication. In addition, tumor penetration ability was rendered by the electrostatic adsorption of the albumin on the surface of the nanoparticles. The Alb-PLP/NO NPs showed enhanced intracellular NO delivery efficiency and cytotoxicity to B16F10 murine melanoma cells. In B16F10-tumor-bearing mice, the Alb-PLP/NO NPs showed improved extracellular matrix penetration and spatial distribution in the tumor tissue after intratumoral injection, resulting in enhanced antitumor activity. Taken together, the results suggest that Alb-PLP/NO NPs represent a promising new modality for the local treatment of melanoma.

PEI/NONOates-doped PLGA nanoparticles for eradicating methicillin-resistant Staphylococcus aureus biofilm in diabetic wounds via binding to the biofilm matrix.

Wounds infected with methicillin-resistant Staphylococcus aureus (MRSA) biofilm represent a high risk in patients with diabetes. Nitric oxide (NO) has shown promise in dispersing biofilm and wound healing. For an effective treatment of MRSA biofilm-infected wounds, however, NO needs to be supplied to the biofilm matrix in a sustainable manner due to a short half-life and limited diffusion distance of NO. In this study, polyethylenimine/diazeniumdiolate (PEI/NONOate)-doped PLGA nanoparticles (PLGA-PEI/NO NPs) with an ability to bind to the biofilm matrix are developed to facilitate the NO delivery to MRSA biofilm-infected wound. In simulated wound fluid, PLGA-PEI/NO NPs show an extended NO release over 4 days. PLGA-PEI/NO NPs firmly bind to the MRSA biofilm matrix, resulting in a greatly enhanced anti-biofilm activity. Moreover, PLGA-PEI/NO NPs accelerate healing of MRSA biofilm-infected wounds in diabetic mice along with complete biofilm dispersal and reduced bacterial burden. These results suggest that the biofilm-binding NO-releasing NPs represent a promising NO delivery system for the treatments of biofilm-infected chronic wounds.

Evaluation of cellulose xanthate-metal-tetracycline complexes as a polymeric antibacterial agent with prolonged antibacterial activity.

Cellulose xanthate-metal-tetracycline complexes (MCX-metal-Tc) were prepared and evaluated as a controlled release system for the antibiotics. Microcrystallized cellulose was chemically modified to cellulose xanthate (MCX). The amount of metal bound to MCX was 0.36 mmol Cu(II)/g MCX and 0.26 mmol Zn(II)/g MCX. Tetracycline (Tc) bound to MCX-metal chelates was 0.08 mmol/g MCX-Cu(II) and 0.04 mmol/g MCX-Zn(II). The Tc release from MCX-metal-Tc was greatly sustained compared with that from a mixture of cellulose/metal/Tc. Furthermore, MCX-metal-Tc manifested antibacterial activity that lasted for 7-22 days. These results suggest that MCX-metal-Tc is a polymeric antibacterial agent with prolonged antibacterial activity.

S-Nitrosoglutathione loaded poly(lactic-co-glycolic acid) microparticles for prolonged nitric oxide release and enhanced healing of methicillin-resistant Staphylococcus aureus-infected wounds.

Methicillin-resistant Staphylococcus aureus (MRSA)-infected wounds have become a significant clinical issue worldwide. Recently, nitric oxide (NO) has emerged as a potent antibacterial agent against MRSA infections and a wound-healing enhancer. Nevertheless, clinical applications of NO have been largely restricted by its gaseous state and short half-life. In this study, our aim was to develop S-nitrosoglutathione (GSNO, an endogenous NO donor)-loaded poly(lactic-co-glycolic acid) [PLGA] microparticles (GSNO-MPs) that release NO over a prolonged period, to accelerate the healing of MRSA-infected wounds with less frequent dosing. GSNO was successfully encapsulated into PLGA microparticles by a solid-in-oil-in-water emulsion solvent evaporation method. Scanning electron microscopy and X-ray diffraction analyses confirmed the successful fabrication of GSNO-MPs. The latter released NO in a prolonged manner over 7 days and exerted a remarkable antibacterial activity against MRSA in a concentration- and time-dependent manner. Moreover, GSNO-MPs had good antibacterial efficacy and were found to accelerate wound healing in a mouse model of MRSA-infected wounds. Therefore, NO-releasing MPs devised in this study may be a promising option for the treatment of cutaneous wounds infected by drug-resistant bacteria such as MRSA.

Colon-targeted dexamethasone microcrystals with pH-sensitive chitosan/alginate/Eudragit S multilayers for the treatment of inflammatory bowel disease.

Oral colon-targeted drug delivery has gained popularity as an effective strategy for treatment of inflammatory bowel disease (IBD). In this study, we prepared colon-targeted dexamethasone microcrystals (DXMCs) coated with multilayers of chitosan oligosaccharide (CH), alginate (AG), and finally Eudragit S 100 (ES) (ES1AG4CH5-DXMCs) using a layer-by-layer (LBL) coating technique. Particle size, surface charge, in vitro drug release, and in vivo anti-inflammatory activity of ES1AG4CH5-DXMCs were evaluated. ES1AG4CH5-DXMCs had an average particle size of 2.34 ±â€¯0.19 µm and a negative surface charge of - 48 ±â€¯9 mV. ES1AG4CH5-DXMCs demonstrated pH-dependent dexamethasone release, avoiding initial burst drug release in acidic pH conditions of the stomach and small intestine, and providing subsequent sustained drug release in the colonic pH. Importantly, ES1AG4CH5-DXMCs exhibited a significant therapeutic activity in a mouse model of colitis compared to other DXMCs. Overall, the LBL-coated DXMCs presented here could be a promising colon-targeted therapy for IBD.

Colon-targeted delivery of cyclosporine A using dual-functional Eudragit® FS30D/PLGA nanoparticles ameliorates murine experimental colitis.

BACKGROUND: Colon-targeted oral nanoparticles (NPs) have emerged as an ideal, safe, and effective therapy for ulcerative colitis (UC) owing to their ability to selectively accumulate in inflamed colonic mucosa. Cyclosporine A (CSA), an immunosuppressive agent, has long been used as rescue therapy in severe steroid-refractory UC. In this study, we developed CSA-loaded dual-functional polymeric NPs composed of Eudragit® FS30D as a pH-sensitive polymer for targeted delivery to the inflamed colon, and poly(lactic-co-glycolic acid) (PLGA) as a sustained-release polymer. METHODS: CSA-loaded Eudragit FS30D nanoparticles (ENPs), PLGA nanoparticles (PNPs), and Eudragit FS30D/PLGA nanoparticles (E/PNPs) were prepared using the oil-in-water emulsion method. Scanning electron microscope images and zeta size data showed successful preparation of CSA-loaded NPs. RESULTS: PNPs exhibited a burst drug release of >60% at pH 1.2 (stomach pH) in 0.5 h, which can lead to unwanted systemic absorption and side effects. ENPs effectively inhibited the burst drug release at pH 1.2 and 6.8 (proximal small intestine pH); however, nearly 100% of the CSA in ENPs was released rapidly at pH 7.4 (ileum-colon pH) owing to complete NP dissolution. In contrast to single-functional PNPs and ENPs, the dual-functional E/PNPs minimized burst drug release (only 18%) at pH 1.2 and 6.8, and generated a sustained release at pH 7.4 thereafter. Importantly, in distribution studies in the gastrointestinal tracts of mice, E/PNPs significantly improved CSA distribution to the colon compared with PNPs or ENPs. In a mouse model of colitis, E/PNP treatment improved weight loss and colon length, and decreased rectal bleeding, spleen weight, histological scoring, myeloperoxidase activity, macrophage infiltration, and expression of proinflammatory cytokines compared with PNPs or ENPs. CONCLUSION: Overall, this work confirms the benefits of CSA-loaded E/PNPs for efficiently delivering CSA to the colon, suggesting their potential for UC therapy.

Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester, a polymeric colon-specific prodrug releasing 5-aminosalicylic acid and benzocaine, ameliorates TNBS-induced rat colitis.

Local anesthetics have beneficial effects on colitis. Dextran-5-(4-ethoxycarbonylphenylazo)salicylic acid ester (Dex-5-ESA), designed as a polymeric colon-specific prodrug liberating 5-ASA and benzocaine in the large intestine, was prepared and its therapeutic activity against colitis was evaluated using a TNBS-induced rat colitis model. Dex-5-ESA liberated 5-ASA and benzocaine in the cecal contents while (bio)chemically stable in the small intestinal contents and mucosa. Oral administration of Dex-5-ESA (equivalent to 10 mg 5-ASA/kg, twice a day) alleviated colonic injury and reduced MPO activity in the inflamed colon. In parallel, pro-inflammatory mediators, COX-2, iNOS and CINC-3, elevated by TNBS-induced colitis, were substantially diminished in the inflamed colon. Dex-5-ESA was much more effective for the treatment of colitis than 5-(4-ethoxycarbonylphenylazo)salicylic acid (5-ESA) that may not deliver benzocaine to the large intestine. Our data suggest that Dex-5-ESA is a polymeric colon-specific prodrug, liberating 5-ASA and benzocaine in the target site (large intestine), probably exerting anti-colitic effects by combined action of 5-ASA and benzocaine.

Nitric oxide-releasing poly(lactic-co-glycolic acid)-polyethylenimine nanoparticles for prolonged nitric oxide release, antibacterial efficacy, and in vivo wound healing activity.

Nitric oxide (NO)-releasing nanoparticles (NPs) have emerged as a wound healing enhancer and a novel antibacterial agent that can circumvent antibiotic resistance. However, the NO release from NPs over extended periods of time is still inadequate for clinical application. In this study, we developed NO-releasing poly(lactic-co-glycolic acid)-polyethylenimine (PEI) NPs (NO/PPNPs) composed of poly(lactic-co-glycolic acid) and PEI/diazeniumdiolate (PEI/NONOate) for prolonged NO release, antibacterial efficacy, and wound healing activity. Successful preparation of PEI/NONOate was confirmed by proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, and ultraviolet/visible spectrophotometry. NO/PPNPs were characterized by particle size, surface charge, and NO loading. The NO/PPNPs showed a prolonged NO release profile over 6 days without any burst release. The NO/PPNPs exhibited potent bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa concentration-dependently and showed the ability to bind on the surface of the bacteria. We also found that the NO released from the NO/PPNPs mediates bactericidal efficacy and is not toxic to healthy fibroblast cells. Furthermore, NO/PPNPs accelerated wound healing and epithelialization in a mouse model of a MRSA-infected wound. Therefore, our results suggest that the NO/PPNPs presented in this study could be a suitable approach for treating wounds and various skin infections.

Design of a gelatin microparticle-containing self-microemulsifying formulation for enhanced oral bioavailability of dutasteride.

In this study, a gelatin microparticle-containing self-microemulsifying formulation (SMF) was developed using a spray-drying method to enhance the oral delivery of the poorly water-soluble therapeutic dutasteride. The effect of the amount of gelatin and the type and amount of hydrophilic additives, namely, Gelucire(®) 44/14, poloxamer 407, sodium lauryl sulfate, Soluplus(®), Solutol™ HS15, and D-α-tocopheryl polyethylene glycol 1000 succinate, on the droplet size, dissolution, and oral absorption of dutasteride from the SMF was investigated. Upon dispersion of the gelatin microparticle-containing SMF in water after spray-drying, the mean droplet size of the aqueous dispersion was in the range of 110-137 nm. The in vitro dissolution and recrystallization results showed that gelatin could be used as a solid carrier and recrystallization inhibitor for the SMF of dutasteride. Furthermore, combination of the gelatin microparticle-containing SMF and Soluplus enhanced the dissolution properties and oral absorption of dutasteride. The results of our study suggest that the gelatin microparticle-containing SMF in combination with Soluplus could be useful to enhance the oral absorption of dutasteride.

Improving dissolution and oral bioavailability of pranlukast hemihydrate by particle surface modification with surfactants and homogenization.

The present study was carried out to develop an oral formulation of pranlukast hemihydrate with improved dissolution and oral bioavailability using a surface-modified microparticle. Based on solubility measurements, surface-modified pranlukast hemihydrate microparticles were manufactured using the spray-drying method with hydroxypropylmethyl cellulose, sucrose laurate, and water and without the use of an organic solvent. The hydrophilicity of the surface-modified pranlukast hemihydrate microparticle increased, leading to enhanced dissolution and oral bioavailability of pranlukast hemihydrate without a change in crystallinity. The surface-modified microparticles with an hydroxypropylmethyl cellulose/sucrose laurate ratio of 1:2 showed rapid dissolution of up to 85% within 30 minutes in dissolution medium (pH 6.8) and oral bioavailability higher than that of the commercial product, with approximately 2.5-fold and 3.9-fold increases in area under the curve (AUC 0 → 12 h) and peak plasma concentration, respectively. Therefore, the surface-modified microparticle is an effective oral drug delivery system for the poorly water-soluble therapeutic pranlukast hemihydrate.

Development of megestrol acetate solid dispersion nanoparticles for enhanced oral delivery by using a supercritical antisolvent process.

In the present study, solid dispersion nanoparticles with a hydrophilic polymer and surfactant were developed using the supercritical antisolvent (SAS) process to improve the dissolution and oral absorption of megestrol acetate. The physicochemical properties of the megestrol acetate solid dispersion nanoparticles were characterized using scanning electron microscopy, differential scanning calorimetry, powder X-ray diffraction, and a particle-size analyzer. The dissolution and oral bioavailability of the nanoparticles were also evaluated in rats. The mean particle size of all solid dispersion nanoparticles that were prepared was <500 nm. Powder X-ray diffraction and differential scanning calorimetry measurements showed that megestrol acetate was present in an amorphous or molecular dispersion state within the solid dispersion nanoparticles. Hydroxypropylmethyl cellulose (HPMC) solid dispersion nanoparticles significantly increased the maximum dissolution when compared with polyvinylpyrrolidone K30 solid dispersion nanoparticles. The extent and rate of dissolution of megestrol acetate increased after the addition of a surfactant into the HPMC solid dispersion nanoparticles. The most effective surfactant was Ryoto sugar ester L1695, followed by D-α-tocopheryl polyethylene glycol 1000 succinate. In this study, the solid dispersion nanoparticles with a drug:HPMC:Ryoto sugar ester L1695 ratio of 1:2:1 showed >95% rapid dissolution within 30 minutes, in addition to good oral bioavailability, with approximately 4.0- and 5.5-fold higher area under the curve (0-24 hours) and maximum concentration, respectively, than raw megestrol acetate powder. These results suggest that the preparation of megestrol acetate solid dispersion nanoparticles using the supercritical antisolvent process is a promising approach to improve the dissolution and absorption properties of megestrol acetate.

Colon-targeted delivery of budesonide using dual pH- and time-dependent polymeric nanoparticles for colitis therapy.

Single pH-dependent drug delivery systems have been widely used for colon-targeted delivery, but their efficiency is often hampered by the variation in gut pH. To overcome the limitation of single pH-dependent delivery systems, in this study, we developed and evaluated the therapeutic potential of budesonide-loaded dual pH/time-dependent nanoparticles (NPs) for the treatment of colitis. Eudragit FS30D was used as a pH-dependent polymer, and Eudragit RS100 as a time-dependent controlled release polymer. Single pH-dependent NPs (pH_NPs), single time-dependent NPs (Time_NPs), and dual pH/time-dependent NPs (pH/Time_NPs) were prepared using the oil-in-water emulsion method. The physicochemical properties and drug release profiles of these NPs in gastrointestinal (GI) tract conditions were investigated. The therapeutic potential and in vivo distribution of the NPs were evaluated in a dextran sulfate sodium (DSS)-induced colitis mice model. The pH/Time_NPs prevented a burst drug release in acidic pH conditions and showed sustained release at a colonic pH. The in vivo distribution study in the mice GI tract demonstrated that pH/Time_NPs were more efficiently delivered to the inflamed colon than pH_NPs were. Compared to the single pH_NPs-treated group, the pH/Time_NPs-treated group showed increased body weight and colon length and markedly decreased disease activity index, colon weight/length ratios, histological damage, and inflammatory cell infiltration in colon tissue. Our results demonstrate that the dual pH/time-dependent NPs are an effective oral colon-targeted delivery system for colitis therapy.

Enzyme/pH dual sensitive polymeric nanoparticles for targeted drug delivery to the inflamed colon.

Novel nanoparticles whose drug release profiles are controlled by both enzyme and pH were prepared for the colon-specific drug delivery using a polymeric mixture of enzyme-sensitive azo-polyurethane and pH-sensitive Eudragit S100 (ES-Azo.pu). The enzyme/pH dual sensitive nanoparticles were designed to release a drug based on a two-fold approach which specifically aimed to target drug delivery to the inflamed colon while preventing the burst release of drugs in the stomach and small intestine. Single pH-sensitive (ES) and dual sensitive (ES-Azo.pu) nanoparticles were prepared using an oil-in-water emulsion solvent evaporation method and coumarin-6 (C-6) was used as a model drug. The successful formation of ES and ES-azo.pu nanoparticles that have 214 nm and 244 nm in mean particle size, respectively, was confirmed by scanning electron microscopy and qNano. ES nanoparticles showed almost 100% of burst drug release at pH 7.4, whereas ES-Azo.pu nanoparticles prevented the burst drug release at pH 7.4, followed by a sustained release phase thereafter. Furthermore, ES-Azo.pu nanoparticles exhibited enzyme-triggered drug release in the presence of rat cecal contents obtained from a rat model of colitis. An in vivo localization study in rat gastrointestinal tract demonstrated that ES-Azo.pu nanoparticles were selectively distributed in the inflamed colon, showing 5.5-fold higher C-6 than ES nanoparticles. In conclusion, the enzyme/pH dual sensitive nanoparticles presented in this study can serve as a promising strategy for colon-specific drug delivery against inflammatory bowel disease and other colon disorders.