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Objective: To explore the mechanism of huankuile (HKL) in colon injury repair in rats with ulcerative colitis (UC)., Methods: Fifty SPF Wistar male rats were divided randomly into a normal group, a negative control group, an HKL intervention group ('HKL group') and a 5-aminosalicylic acid intervention group ('5-ASA group'). After 14 days of intervention with corresponding drugs, pathological scores were obtained using the results of immunohistochemical staining; morphological changes were observed by hematoxylin-eosin staining, and the mRNA expression levels of tumour necrosis factor-α (TNF-α), matrix metalloproteinase 9 (MMP9) and interleukin-13 (IL-13) were detected by real-time quantitative PCR., Results: After the successful construction of the rat model, it was compared with the rats in the normal group. In the negative group, it was found that the expression of TNF-α and MMP9 was significantly increased in the colonic mucosal epithelia of the rats, the pathological score was significantly increased (P < 0.05), and the mRNA expression levels of TNF-α, MMP9 and IL-13 were increased (P < 0.05). After treatment with HKL, the colonic morphology of the rats returned to normal, the expression of TNF-α and MMP9 in the colonic mucosal epithelium of the rats returned to normal, the pathological score grade was significantly reduced (P < 0.05), and the mRNA expression levels of TNF-α, MMP9 and IL-13 were reduced; these results were largely consistent with those of the normal group, with no statistically significant difference., Conclusion: HKL effectively improved the general symptoms and tissue injury in UC rats, and the therapeutic effect was better than that of 5-ASA group. Ulcerative colitis in rats increased the expression of TNF-α, MMP9 and IL-13. HKL repaired UC-induced colonic injury in rats by decreasing the expression of TNF-α, MMP9 and IL-13., (© 2024. The Author(s).)

Eudragit S100-coated bile salt-containing liposomes were prepared and optimized by experimenting with different variables, including bile salt type and concentration, and the method of incorporation into liposomes using a model hydrophilic compound, 5-aminosalicylic acid (5-ASA). After optimizing the formulation, cellular uptake, and animal pharmacokinetic experiments were performed. The inclusion of sodium glycocholate (SG) into liposomes decreased liposome particle size and entrapment efficiency significantly but had no effect on zeta potential. The method of incorporating SG into the lipid or aqueous phase of the liposome did not notably impact the characteristics of the liposomes but the hydration media had a substantial effect on the entrapment efficiency of 5-ASA. In vitro drug release in different fluids simulating distinct gastrointestinal tract sections, indicated pH-dependent disintegration of the coating layer of coated SG-containing liposomes. The majority of the drug was retained when subjected to simulated gastric fluid (SGF) and fed-state simulated intestinal fluid (FeSSIF) (≈ 37% release after 2 h in SGF pH 1.2, followed by 3 h in FeSSIF pH 5). The remaining drug was subsequently released in phosphate-buffered saline pH 7.4 (≈ 85% release within 24 h). Increasing SG concentration in the liposomes decreased the amount of drug released in FeSSIF. Similar results were observed when SG was replaced with sodium taurocholate. Cellular uptake studies in Caco-2 cells demonstrated that all liposomal formulations (conventional liposomes, bile salt-containing liposomes, and coated bile salt-containing liposomes) have shown to be equally effective at increasing the cellular uptake compared to free fluorescein solution. In the pharmacokinetic study, coated bile salt-containing liposomes showed a lower C max and prolonged residence in the gastrointestinal tract in comparison to conventional liposomes. Taken together, these findings suggest that the polymer-coated bile salt-containing liposomes have the potential to serve as a drug delivery system targeted at the colon., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

The aggressiveness and recurrence of cancer is linked to cancer stem cells (CSCs), but drugs targeting CSCs may not succeed in the clinic due to the lack of a distinct CSC subpopulation. Clinical Pt(II) drugs can increase stemness. We screened 15 Ru II or Ir III complexes with mesalazine or 3-aminobenzoate Schiff bases of the general formulas [Ru(p-cym)L] + , [Ru(p-cym)L], and [Ir(Cp*)L] + (L = L1 - L9 ) and found three complexes ( 2 , 12 , and 13 ) that are active against oral squamous cell carcinoma (OSCC) CSCs. There is a putative oncogenic role of transcription factors (viz. NOTCH1, SOX2, c-MYC) to enhance the stemness. Our work shows that imidazolyl-mesalazine ester-based Ru II complexes inhibit growth of CSC-enriched OSCC 3D spheroids at low micromolar doses (2 μM). Complexes 2 , 12 , and 13 reduce stemness gene expression and induce differentiation markers ( Involucrin , CK10 ) in OSCC 3D cultures. The imidazolyl-mesalazine ester-based Ru II complex 13 shows the strongest effect. Downregulating c-MYC suggests that Ru II complexes may target c-MYC-driven cancers.

Ulcerative colitis (UC) is a global inflammatory bowel disease. This study aimed to assess the effects of icosapent ethyl on acetic acid-induced colitis in rats as well as the underlying mechanisms involved. 36 male Wister rats were equally divided into six groups: control, UC, mesalamine 100 mg/kg, icosapent 150mg/kg, icosapent 300 mg/kg, and EX527-icosapent 300 mg/kg groups. Except for control group, UC was induced by acetic acid instillation into colon. Drugs were administered once daily for one week then under thiopental anaesthesia, colons were excised. Colitis macroscopic and microscopic scores were assessed. A part of colon was homogenized for detection of malondialdehyde (MDA), inerleukin1 (IL-1β), tumor necrosis factor (TNF-α), superoxide dismutase (SOD), phosphorylated Akt (pAkt) and caspase 3 levels. Silent information regulator 1 (SIRT1), heme oxygenase 1 (HO-1), and nuclear factor erythroid 2 (Nrf2) mRNA expressions were detected. Mallory-stained colonic sections were examined for collagen fibres detection. Immunohistochemistry of NF-κB and p53 expressionsin colonic sections were assessed. Acetic acid induced colitis with increments in MDA, IL-1β, TNF-α, and caspase 3 levels while decreased SOD, pAkt, SIRT1, HO-1, and Nrf2 with increased collagen fibres as well as NF-κB and p53. Icosapent decreased macro& microscopic colitis scores, MDA, IL-1β, TNF-α, and caspase 3 levels while increased SOD, pAkt, SIRT1, HO-1, and Nrf2 with decreased collagen fibres as well as NF-κB and p53. The effects of icosapent 300 mg/kg were similar to mesalamine. Icosapent effects were antagonized by EX527. Icosapent alleviated acetic acid-induced colitis via its anti-inflammatory, antioxidant, and anti-apoptotic effects mediated in part by SIRT1 pathway activation., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

The anti-inflammatory 5-aminosalicylic acid (5-ASA) is the main therapeutic option used to prevent and treat inflammatory bowel diseases. The upper intestinal tract performs rapid and almost complete absorption of this drug when administered orally, making local therapeutic levels of the molecule in the inflamed colonic mucosa difficult to achieve. Micro and nanoparticle systems are promising for 5-ASA incorporation because the reduced dimensions of these structures can improve the drug's pharmacodynamics and contribute to more efficient and localized therapy. Together, the association of these systems with polymers will allow the release of 5-ASA through specific targeting mechanisms to the colon, as demonstrated in the mesalazine modified-release dosage form. This review will summarize and discuss the challenges for the oral administration of 5-ASA and the different colon-specific delivery strategies using polymers., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background: Qingchang Wenzhong Decoction (QCWZD), a chinese herbal prescription, is widely used for ulcerative colitis (UC). Nevertheless, the active ingredients and mechanism of QCWZD in UC have not yet been explained clearly., Purpose: This research focuses on the identification of the effective ingredients of QCWZD and the prediction and verification of their potential targets., Methods: The UC mice were established by adding 3.0% dextran sulfate sodium (DSS) to sterile water for one week. Concurrently, mice in the treatment group were gavage QCWZD or mesalazine. LC-MS analyzed the main components absorbed after QCWZD treatment, and network pharmacology predicted their possible targets. ELISA, qPCR, immunohistochemistry and immunofluorescence experiments were used to evaluate the colonic inflammation level and the intestinal barrier completeness. The percentage of Th17 and Treg lymphocytes was detected by flow cytometry., Results: After QCWZD treatment, twenty-seven compounds were identified from the serum. In addition, QCWZD treatment significantly reduced the increased myeloperoxidase (MPO) and inflammatory cell infiltration caused by DSS in the colonic. In addition, QCWZD can reduce the secretion of inflammatory factors in serum and promote the expression of mRNAs and proteins of occludin and ZO-1. Network pharmacology analysis indicated that inhibiting IL-6-STAT3 pathway may be necessary for QCWZD to treat UC. Flow cytometry analysis showed that QCWZD can restore the normal proportion of Th17 lymphocytes in UC mice. Mechanistically, QCWZD inhibited the phosphorylation of JAK2-STAT3 pathway, reducing the transcriptional activation of RORγT and IL-17A., Conclusions: Overall, for the first time, our work revealed the components of QCWZD absorbed into blood, indicated that the effective ingredients of QCWZD may inhibit IL-6-STAT3 pathway and inhibit the differentiation of Th17 lymphocytes to reduce colon inflammation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022. Published by Elsevier GmbH.)

Necrotizing enterocolitis (NEC) remains a devastating disease that affects preterm infants. Hydrogen sulfide (H 2 S) donors have been shown to reduce the severity of NEC, but the optimal compound has yet to be identified. We hypothesized that oral H 2 S-Mesalamine (ATB-429) would improve outcomes in experimental NEC, and its benefits would be dependent on endothelial nitric oxide synthase (eNOS) pathways. NEC was induced in 5-day-old wild-type (WT) and eNOS knockout (eNOSKO) pups by formula feeding and stress. Four groups were studied in both WT and eNOSKO mice: 1 ) breastfed controls, 2 ) NEC, 3 ) NEC + 50 mg/kg mesalamine, and 4 ) NEC + 130 mg/kg ATB-429. Mesalamine and ATB-429 doses were equimolar. Pups were monitored for sickness scores and perfusion to the gut was measured by Laser Doppler Imaging (LDI). After euthanasia of the pups, intestine and lung were hematoxylin and eosin-stained and scored for injury in a blind fashion. TLR4 expression was quantified by Western blot and IL-6 expression by ELISA. P < 0.05 was significant. Both WT and eNOSKO breastfed controls underwent normal development and demonstrated milder intestinal and pulmonary injury compared with NEC groups. For the WT groups, ATB-429 significantly improved weight gain, reduced clinical sickness score, and improved perfusion compared with the NEC group. In addition, WT ATB-429 pups had a significantly milder intestinal and pulmonary histologic injury when compared with NEC. ATB-429 attenuated the increase in TLR4 and IL-6 expression in the intestine. When the experiment was repeated in eNOSKO pups, ATB-429 offered no benefit in weight gain, sickness scores, perfusion, intestinal injury, pulmonary injury, or decreasing intestinal inflammatory markers. An H 2 S derivative of mesalamine improves outcomes in experimental NEC. Protective effects appear to be mediated through eNOS. Further research is warranted to explore whether ATB-429 may be an effective oral therapy to combat NEC.

Although in-vivo bioequivalence (BE) study serves as a golden standard for establishing interchangeability of oral dosage forms, it remains challenging for products with high inter-subject variability such as mesalazine enteric-coated tablet to fulfil the BE criteria set by regulatory authorities. Mesalazine, as a BCS class IV drug, targets to be delivered to distal ileum or colon with a pH-sensitive polymer coating for the remission of ulcerative colitis. Through population pharmacokinetic (PK) analysis and in-vitro in-vivo correlation (IVIVC) modeling on the dissolution and BE data of a generic enteric-coated product (EM) and its reference Salofalk® 250 mg tablet (SM), we for the first time revealed the underlying mechanism of the high inter-subject variability for such delayed-release formulation. It was also noted that the in-vivo start time of absorption (T s ) for EM and SM was positively correlated with their in-vitro lag time (T lag ) under the USP three-stage dissolution condition and reversely correlated with their in-vivo bioavailability. The varied oral bioavailability of mesalazine enteric-coated tablet was mainly due to the varied N-acetyltransferase activities along GI tract. Although such extensive intestinal first-pass metabolism with large individual differences led to a significant variation of mesalazine C max (coefficient of variation: 60-63.5%) and AUC 0-t (coefficient of variation: 37.5-46.9%), the corresponding variations in the total absorbed mesalazine (mesalazine and its metabolite N-acetyl mesalazine) were significantly reduced by 12 to 45%. Since the BE purpose for mesalazine enteric-coated tablet focused on their comparable safety profiles, total absorbed mesalazine was recommended to be adopted for the development of the IVIVC model and BE evaluation for EM. All in all, our model-based approach has not only successfully identified the key factors that affect the BE of EM to guide its further formulation optimization, but also demonstrated the indispensable role of modeling in the development of generic pharmaceutical product at its early stages., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: There is an obvious correlation between ulcerative colitis and colorectal cancer, and the risk of colorectal cancer in patients with ulcerative colitis is increasing. Therefore, the combination therapy of anti-inflammatory and anti-tumor drugs may show promising to inhibit colon cancer. 5-aminosalicylic acid (5-ASA) with anti-inflammatory function is effective for maintaining remission in patients with ulcerative colitis and may also reduce colorectal cancer risk. Histone deacetylase (HDAC) plays an essential role in the progression of colon cancer. Butyric acid (BA) is a kind of HDAC inhibitor and thus shows tumor suppression to colon cancer. However, the volatile and corrosive nature of BA presents challenges in practical application. In addition, its clinical application is limited due to its non-targeting ability and low bioavailability. We aimed to synthesize a novel dual-prodrug of 5-ASA and BA, referred as BBA, to synergistically inhibit colon cancer. Further, based on the fact that folate receptor (FR) is over-expressed in most solid tumors and it has been identified to be a cancer stem cell surface marker in colon cancer, we took folate as the targeting ligand and used carboxymethyl-β-cyclodextrin (CM-β-CD) to carry BBA and thus prepared a novel inclusion complex of BBA/FA-PEG-CM-β-CD., Results: It was found that BBA/FA-PEG-CM-β-CD showed significant inhibition in cell proliferation against colon cancer cells SW620. It showed a pro-longed in vivo circulation and mainly accumulated in tumor tissue. More importantly, BBA/FA-PEG-CM-β-CD gave great tumor suppression effect against nude mice bearing SW620 xenografts., Conclusions: Therefore, BBA/FA-PEG-CM-β-CD may have clinical potential in colon cancer therapy., (© 2021. The Author(s).)

Background and Aim: Limited data are available on the effects of fermentable fiber in altering intestinal pH and transit to predict efficacy-based delivery profiles of pH-dependent mesalamine coatings in ulcerative colitis (UC). This study aimed to examine regional pH and transit after acute changes in fermentable fiber intake in quiescent UC patients and their effects on drug release systems., Methods: In a randomized, double-blind study, 18 patients with quiescent UC and 10 healthy controls were supplied meals high (13 g) or low (≤ 2 g) in fermentable fiber and subsequently ingested a wireless pH-motility capsule. After a ≥ 3-day washout, they crossed over to the other diet. Measurements of intestinal pH and transit were used to predict drug release for the various pH-dependent coatings., Results: Increasing fermentable fiber intake lowered overall (median 6.2 [6.1-6.7] vs low: 6.9 [range or interquartile range: 6.4-7.4]; P = 0.01) and distal pH (7.8 [7.3-8.1] vs 8.2 [8.0-8.5]; P = 0.04) in controls. In UC patients, only cecal pH was decreased (high: 5.1 [4.8-5.5] vs low: 5.5 [5.3-5.7]; P < 0.01). Colonic transit in the UC cohort varied widely after a low-fiber intake but tended to normalize after the high fermentable fiber intake. Hypothetical coating dissolution profiles were heterogeneous in UC patients, with a multi-matrix delayed release system having the highest likelihood of patients (20-40%) with incomplete dissolution, and predominant small intestinal dissolution predicted for Eudragit L (94% patients) and S (44-69%)., Conclusions: Patients with quiescent UC have abnormalities in intestinal pH and transit in response to acute changes in fermentable fiber intake. These have potentially detrimental effects on predicted luminal release patterns of pH-dependent 5-aminosalicylic acid release systems., (© 2020 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

A dual pH-/thermo-responsive hydrogel was designed based on a polyelectrolyte complex of polyacrylic acid (PAA) and norbornene-functionalized chitosan (CsNb), which was synergized with chemical crosslinking using bistetrazine-poly(N-isopropyl acrylamide) (bisTz-PNIPAM). The thermo-responsive polymeric crosslinker, bisTz-PNIPAM, was synthesized via reversible addition-fragmentation transfer polymerization of NIPAM. FTIR, XRD, rheological and morphological analyses demonstrated the successful formation of the polyelectrolyte network. The highly porous structure generated through the in-situ "click" reaction between Tz and Nb resulted in a higher drug loading (29.35 %). The hydrogel (COOH/NH 2 mole ratio of 3:1) exhibited limited drug release (8.5 %) of 5-ASA at a pH of 2.2, but it provided an almost complete release (92 %) at pH 7.4 and 37 °C within 48 h due to the pH responsiveness of PAA, hydrogel porosity, and shrinkage behavior of PNIPAM. The hydrogels were biodegradable and non-toxic against human fibroblast cells, suggesting their considerable potential for a colon-targeted drug delivery system., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis (UC), is a chronic disease characterized by diffuse mucosal inflammation limited to the colon. Topical drug delivery systems that could be facilely performed and efficiently retained at colon sites are attractive for clinical IBD treatment. Herein, we report the exploration of an injectable thermosensitive copolymer hydrogel as a topical formulation for IBD treatment and demonstrate its feasibility in UC treatment by shielding ulcer sites from the external environment and being a drug reservoir for sustained release. Poly(aliphatic ester)-based triblock copolymer, poly(dl-lactic acid)-poly(ethylene glycol)-poly(dl-lactic acid) (PDLLA-PEG-PDLLA), adopts the solution state at room temperature yet a gel state at body temperature when the polymer concentration is more than 11%. The gel acts not only as a physical mucosal barrier for protecting ulcer sites from microorganisms like bacteria but also as a mesalazine depot for enhanced drug retention in the colon for localized, sustained drug release. In vivo UC treatment reveals that blank gel as a mucosal protector shows nearly the same treatment effect to mesalazine SR granules. Mesalazine-loaded gel significantly suppresses inflammation and has the best outcomes of indices such as colonic length, mucosal injury index, pathological tissue, and inflammatory factor. The injectable thermosensitive polymer hydrogel represents a novel, robust platform for the efficient treatment of IBD by acting as a physical shield to block out the pro-inflammatory factors as well as a drug depot for enhanced drug retention and controlled delivery.

Xylan extracted from corn cobs was used to produce mesalamine-loaded xylan microparticles (XMP5-ASA) by cross-linking polymerization using a non-hazardous cross-linking agent. The microparticles were characterized by thermal analysis (DSC/TG), X-ray diffraction (XRD), Infrared spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). A comparative study of the in vitro drug release from XMP5-ASA and from gastro-resistant capsules filled with XMP5-ASA (XMPCAP5-ASA) or 5-ASA was also performed. NMR, FTIR-ATR, XRD and DSC/TG studies indicated molecularly dispersed drug in the microparticles with increment on drug stability. The release studies showed that XMPCAP5-ASA allowed more efficient drug retention in the simulated gastric fluid and a prolonged drug release lasting up to 24 h. XMPCAP5-ASA retained approximately 48 % of its drug content after 6 h on the drug release assay. Thus, the encapsulation of 5-ASA into xylan microparticles together with gastro-resistant capsules allowed a better release control of the drug during different simulated gastrointestinal medium., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

We report here an extensive structure-activity relationship study of balsalazide, which was previously identified in a high-throughput screening as an inhibitor of Sirt5. To get a closer understanding why this compound is able to inhibit Sirt5, we initially performed docking experiments comparing the binding mode of a succinylated peptide as the natural substrate and balsalazide with Sirt5 in the presence of NAD + . Based on the evidence gathered here, we designed and synthesized 13 analogues of balsalazide, in which single functional groups were either deleted or slightly altered to investigate which of them are mandatory for high inhibitory activity. Our study confirms that balsalazide with all its given functional groups is an inhibitor of Sirt5 in the low micromolar concentration range and structural modifications presented in this study did not increase potency. While changes on the N-aroyl-β-alanine side chain eliminated potency, the introduction of a truncated salicylic acid part minimally altered potency. Calculations of the associated reaction paths showed that the inhibition potency is very likely dominated by the stability of the inhibitor-enzyme complex and not the type of inhibition (covalent vs. non-covalent). Further in-vitro characterization in a trypsin coupled assay determined that the tested inhibitors showed no competition towards NAD + or the synthetic substrate analogue ZKsA. In addition, investigations for subtype selectivity revealed that balsalazide is a subtype-selective Sirt5 inhibitor, and our initial SAR and docking studies pave the way for further optimization., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Masson SAS. All rights reserved.)

Background and Aim: 5-Aminosalicylic acid (5-ASA) is a fundamental treatment for mild-to-moderate ulcerative colitis (UC). 5-ASA is taken up into the colonic mucosa and metabolized to N-acetyl-5-ASA (Ac-5-ASA). Few studies have assessed whether mucosal 5-ASA and Ac-5-ASA concentrations are associated with endoscopic remission. This study aimed to investigate differences in 5-ASA and Ac-5-ASA concentrations according to endoscopic activity., Methods: This single-center, prospective, cross-sectional study was conducted between March 2018 and February 2019. UC patients who were administered with 5-ASA medication for at least 8 weeks before sigmoidoscopy were enrolled. Mucosal 5-ASA and Ac-5-ASA concentrations were measured using liquid chromatography with tandem mass spectrometry. The primary endpoint was defined as the difference in mucosal concentrations of 5-ASA and Ac-5-ASA, according to the Mayo endoscopic subscore (MES)., Results: Mucosal concentrations were analyzed in 50 patients. In the sigmoid colon, the median 5-ASA concentration in patients with MES of 0 (17.3 ng/mg) was significantly higher than MES ≥ 1 (6.4 ng/mg) (P = 0.019). The median 5-ASA concentrations in patients with Ulcerative Colitis Endoscopic Index of Severity ≤ 1 (16.4 ng/mg) were also significantly higher than in patients with Ulcerative Colitis Endoscopic Index of Severity ≥ 2 (4.63 ng/mg) (P = 0.047). In the sigmoid colon, the concentration of Ac-5-ASA was higher in patients with MES of 0 (21.2 ng/mg) than in patients with MES ≥ 1 (5.81 ng/mg) (P = 0.022)., Conclusions: The present study showed that mucosal Ac-5-ASA concentrations, as well as 5-ASA concentrations, are higher in UC patients with endoscopic remission. Ac-5-ASA may be useful for a biomarker of 5-ASA efficacy., (© 2020 The Authors. Journal of Gastroenterology and Hepatology published by Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Inflammatory bowel disease (IBD) is a debilitating condition, estimated to affect 7 million people worldwide. Current IBD treatment strategies are substandard, relying on colonic targeting using the pH gradient along the gastrointestinal tract. Here, we describe an innovative colonic targeting concept, OPTICORE™ coating technology. OPTICORE™ combines two release triggers (pH and enzyme: Phloral™) in the outer layer, with an inner layer promoting a release acceleration mechanism (Duocoat™). The technology comprises an inner layer of partially neutralized enteric polymer with a buffer agent and an outer layer of a mixture of Eudragit® S and resistant starch. 5-aminosalicylic acid (5-ASA) tablets were coated with different inner layers, where the type of polymer, buffer salt concentration and pH of neutralization, were investigated for drug release acceleration. Buffer capacity of polymethacrylate neutralized polymer significantly contributes to the buffer capacity of the inner layer formulation, while buffer salt concentration is a major contributor to dispersion buffer capacity in the case of hypromellose enteric polymer formulations. An interplay between buffer capacity, pH and ionic strength contributes to an accelerated drug release. Resistant starch does not impact the enteric properties but allows for drug release mediated by colonic bacterial enzymes, ensuring complete drug release. Therefore, OPTICORE™ technology is designed to offer significant advantages over standard enteric coatings, particularly allowing for more accurate colonic drug delivery in ulcerative colitis patients., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: OPTICORE™ coating technology is patented by Tillotts Pharma AG. Felipe Varum and Roberto Bravo do not hold any commercial rights on the use of the technology. Phloral™ technology has been developed and is proprietary technology of UCL School of Pharmacy., (Copyright © 2020 Elsevier B.V. All rights reserved.)

5-Aminosalicylic acid (5-ASA) is conventionally used as a first line drug for inflammatory bowel disease (IBD). Because 5-ASA is well absorbed in the small intestine, very high dose of 5-ASA is required to deliver it to the large intestine which is a target site. Interestingly, 5-ASA is reported to be transported into the large intestine as well as the small intestine via unknown transport system. In a heterologous expression system using Xenopus oocytes, sodium-coupled monocarboxylate transporter 1 (SMCT1) has been reported to accept 5-ASA as a substrate. Although SMCT1 is found to be expressed in the large intestine, it is unknown whether SMCT1 is responsible for 5-ASA absorption from the large intestine or not. Here we determined the transport characteristics of 5-ASA in the isolated everted sac prepared from mouse large intestine. Na + -dependent uptake of [ 3 H]nicotinate, a substrate for SMCT1, in mouse colon was competitively inhibited by 5-ASA with IC 50 value of 2.8 mM. In addition to nicotinate, 5-ASA uptake in mouse colonic mucosa was Na + -dependent and saturable with Michaelis constant (K m ) of 2.4 mM. Na + -activation kinetics revealed that the Na + -to-5-ASA stoichiometry was 2:1 and concentration of Na + necessary for half-maximal transport (K 0.5 Na ) was 36.1 mM. Na + -dependent 5-ASA uptake was competitively inhibited by nicotinate with an inhibitory constant (K i ) of 2.1 mM was comparable to the K m value of Na + -dependent nicotinate uptake (0.99 mM). Furthermore, ibuprofen, a selective SMCT1 inhibitor, was found to have a significantly inhibitory effect on the Na + -dependent 5-ASA uptake in mouse colon (IC 50  = 0.19 mM). Taken collectively, these results indicated that SMCT1 in the mouse colonic mucosa is responsible for Na + -dependent 5-ASA uptake., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The efficacy of 5-aminosalicylic acid (5-ASA) as the first-line therapy for ulcerative colitis (UC) is determined by the extent of drug delivery to the inflamed region. Moreover, differences among the various formulations influence delivery of the drug. In this study, we examined the clinical significance of colonic mucosal concentrations of 5-ASA and N-acetylmesalamine (Ac-5-ASA) in UC patients receiving a pH-dependent or time-dependent release formulation of 5-ASA. The subjects were 67 patients with UC who were treated with a pH-dependent or time-dependent formulation of 5-ASA between December 2011 and April 2014. A retrospective observational analysis of clinical outcomes was performed using the clinical activity index (CAI) obtained on the day of biopsy. Colonic mucosal concentrations of 5-ASA and Ac-5-ASA in biopsy samples were measured by LC-tandem mass spectrometry/mass spectrometry. Patients who were treated with the pH-dependent formulation had higher colon mucosal concentrations of 5-ASA than those who were treated with the time-dependent formulation. Additionally, 5-ASA concentration was significantly higher in patients with CAI scores ≤3. A higher concentration of Ac-5-ASA was achieved with the time-dependent formulation than with the pH-dependent formulation. Furthermore, patients with CAI scores ≤3 had higher concentrations of 5-ASA than those with CAI scores ≥4. The colonic mucosal concentration of 5-ASA in patients with UC is influenced by the pharmaceutical formulation and the remission status of UC.

Better prescription assistance can be provided by applying basic pharmaceutical science concepts, and by considering evidence from clinical trials. For example, several drugs are currently used to treat ulcerative colitis (UC), a form of inflammatory bowel disease. In general, after a drug is administered, it is first absorbed into the upper part of the small intestine and then enters the bloodstream. However, 5-aminosalicylic acid (5-ASA), which is commonly used to treat UC, acts locally on the colonic mucosa; its absorption must be prevented in the upper gastrointestinal tract so that it can be delivered to the colorectal mucosa. Therefore, in this case, it is important to consider drug dissolution tests rather than pharmacokinetics. Currently, three types of 5-ASA formulations are available: a pH-dependent release formulation, a time-dependent release formulation, and a combination of the two at maximum dosages of 3600, 4000, and 4800 mg, respectively. Although it is often thought that selecting a high dose is better, the clinical effectiveness of 5-ASA is determined by the amount of drug actually delivered to the lesion. Therefore, rather than dosage, it is most important to understand differences in drug solubility. It is beneficial to provide prescription assistance for the treatment of UC by 5-ASA, because when 5-ASA fails, a steroid or expensive biological drug is administered. We will present a case study and discuss the future of prescription assistance using Academic Detailing.

The aim of this work is to produce calcium pectin-silica gel beads containing mesalazine as a drug model in order to control the drug release in the colon. The mesalazine loaded calcium pectin-silica gel beads were prepared using the ionotropic gelation method. Energy-dispersive X-ray analysis revealed that increasing the Na 2 SiO 3 concentration led to an increase of the silicon content on the surface and in the cross-sections of the beads. The addition of Na 2 SiO 3 to the gel formulations made from the duckweed callus culture pectin led to a decrease in the swelling degree that appeared to be related to the higher gel strength of these beads. The beads made from pectins of campion and duckweed callus cultures with adding of 22.2 mg/ml of Na 2 SiO 3 showed the lowest release of mesalazine in simulated gastric and intestinal fluids. An increase in the reaction time up to 60 min during incubation in the cross-linking solution of CaCl 2 led to a slower release of drug from the beads. An elevated release of mesalazine was achieved in the simulated colonic fluid. Prepared calcium pectin-silica gel beads containing mesalazine as a drug model can be proposed for controlled drug release in the colon., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Excessive hydrogen sulfide (H 2 S) production from gut microbial metabolism may have clinically important relevance in the pathogenesis of gut disorders, including ulcerative colitis. However, little is known regarding factors that alter its production. Using a newly-designed in vitro gas-profiling technology, the study aimed to verify real-time H 2 S measurement reproducibility and thereafter, assess its production following exposure to dietary factors and 5-aminosalicylate acid (5-ASA). Measurements of H 2 S, carbon dioxide, hydrogen and methane measurements were compared between gas-profiling systems. Homogenized slurries were prepared from freshly-passed healthy human feces. Fifty ml slurries were aliquoted into separate fermentation chambers and substrates added including 1 g highly fermentable fructo-oligosaccharides (FOS) or resistant starch Hi-Maize (RS), or minimally fermentable psyllium or sterculia, 1 g cysteine, 0.9 g sodium sulfate or 1.2 mL of 1 M 5-ASA alone or in combinations. H 2 S release was sampled every 5 mins over 4-h and expressed relative to unspiked controls. RS suppressed H 2 S production by a mean 89.0 (SEM 4.8)% and FOS by 82.2 (6.2)% compared to <35 (17)% by psyllium and sterculia (p<0.001, two-way ANOVA). Cysteine stimulated H 2 S production by 1557 (532)%. The addition of FOS to slurries containing cysteine significantly suppressed H 2 S by 90 (2)% over the addition of 5-ASA (0.3 (2)%, p<0.001). Sulfate and 5-ASA had minimal overall effects. In conclusion, the H 2 S-profiling technology is a reproducible tool. Production of H 2 S is greatly enhanced by sulfur-amino acids but not inorganic sulfate, and is effectively suppressed by readily fermentable fibers. These findings inform potential designs of dietary therapies to reduce H 2 S production in vivo.

The aim of this study was to prepare and characterize a novel type of starch-coated microparticles (MPs) allowing site-specific delivery of bioactives to the colon. An oral colon-specific controlled-release system was developed in the form of MPs coated with a resistant starch (RS2/RS3) film (RS@MPs) through an aqueous suspension coating process. The RS2 was chosen from a high-amylose cornstarch with 88.5% digestion resistibility. The RS3 was prepared by a high-temperature/pressure (HTP) treatment, with the following of enzymatic debranching, and retrogradation, resulting in a dramatic increase in enzymatic resistance (RS3 content: 76.6%). RS@MPs showed 40.7% of 5-aminosalicylic acid release within 8 h. The in vivo study of fluorescein-loaded RS@MPs indicated the high acidic and enzymatic resistibility of RS@MPs and a restrained release in the upper GIT. Therefore, RS@MPs has revealed to be a high potential system for accurately targeting bioactive compound delivery to the colon., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Significant alterations of intestinal microbiota and anemia are hallmarks of inflammatory bowel disease (IBD). It is widely accepted that iron is a key nutrient for pathogenic bacteria, but little is known about its impact on microbiota associated with IBD. We used a model device to grow human mucosa-associated microbiota in its physiological anaerobic biofilm phenotype. Compared to microbiota from healthy donors, microbiota from IBD patients generate biofilms ex vivo that were larger in size and cell numbers, contained higher intracellular iron concentrations, and exhibited heightened virulence in a model of human intestinal epithelia in vitro and in the nematode Caenorhabditis elegans. We also describe an unexpected iron-scavenging property for an experimental hydrogen sulfide-releasing derivative of mesalamine. The findings demonstrate that this new drug reduces the virulence of IBD microbiota biofilms through a direct reduction of microbial iron intake and without affecting bacteria survival or species composition within the microbiota. Metabolomic analyses indicate that this drug reduces the intake of purine nucleosides (guanosine), increases the secretion of metabolite markers of purine catabolism (urate and hypoxanthine), and reduces the secretion of uracil (a pyrimidine nucleobase) in complex multispecies human biofilms. These findings demonstrate a new pathogenic mechanism for dysbiotic microbiota in IBD and characterize a novel mode of action for a class of mesalamine derivatives. Together, these observations pave the way towards a new therapeutic strategy for treatment of patients with IBD.

Purpose: Evaluate ex vivo the bacterial metabolism induced degradation rates of mesalamine (negative control), metronidazole and olsalazine in distal ileum and in cecum., Methods: The contents of distal ileum and cecum were collected during colonoscopy under anaerobic conditions from twelve healthy adults in the fasted and in the fed state. To eliminate potential effects of enzymes that may exist in the fluid of lower intestine, each sample was ultracentrifuged and the precipitate was diluted with a volume of normal saline equivalent to that of the supernatant, after ultracentrifugation of intestinal contents from which the specific precipitate had been obtained. Degradation of the three model drugs in individual materials was evaluated anaerobically., Results: Mesalamine was stable in all cases. Degradation rates of metronidazole and olsalazine were higher in cecum than in distal ileum, only in the fasted state; no trend could be observed in the fed state. Degradation rates of metronidazole and olsalazine were decreased in the fed state in the cecum; no trend could be observed in distal ileum., Conclusions: In the fasted state, bacterial activity is higher in cecum than in distal ileum. Food residues decrease bacterial metabolism degradation rates of drugs in cecum., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The 1,125-bp mabB gene encoding 5-aminosalicylate (5ASA) 1,2-dioxygenase, a nonheme iron dioxygenase in the bicupin family that catalyzes the cleavage of the 5ASA aromatic ring to form cis -4-amino-6-carboxy-2-oxohexa-3,5-dienoate in the biodegradation of 3-aminobenzoate, was cloned from Comamonas sp. strain QT12 and characterized. The deduced amino acid sequence of the enzyme has low sequence identity with that of other reported ring-cleaving dioxygenases. MabB was heterologously expressed in Escherichia coli cells and purified as a His-tagged enzyme. The optimum pH and temperature for MabB are 8.0 and 10°C, respectively. Fe II is required for the catalytic activity of the purified enzyme. The apparent K m and V max values of MabB for 5ASA are 52.0 ± 5.6 μM and 850 ± 33.2 U/mg, respectively. The two oxygen atoms incorporated into the product of the MabB-catalyzed reaction are both from the dioxygen molecule. Both 5ASA and gentisate could be converted by MabB; however, the catalytic efficiency of MabB for 5ASA was much higher (∼70-fold) than that for gentisate. The mabB -disrupted mutant lost the ability to grow on 3-aminobenzoate, and mabB expression was higher when strain QT12 was cultivated in the presence of 3-aminobenzoate. Thus, 5ASA is the physiological substrate of MabB. IMPORTANCE For several decades, 5-aminosalicylate (5ASA) has been advocated as the drug mesalazine to treat human inflammatory bowel disease and considered the key intermediate in the xenobiotic degradation of many aromatic organic pollutants. 5ASA biotransformation research will help us elucidate the microbial degradation of these pollutants. Most studies have reported that gentisate 1,2-dioxygenases (GDOs) can convert 5ASA with significantly high activity; however, the catalytic efficiency of these enzymes for gentisate is much higher than that for 5ASA. This study showed that MabB can convert 5ASA to cis -4-amino-6-carboxy-2-oxohexa-3,5-dienoate, incorporating two oxygen atoms from the dioxygen molecule into the product. Unlike GDOs, MabB uses 5ASA instead of gentisate as the primary substrate. mabB is the first reported 5-aminosalicylate 1,2-dioxygenase gene., (Copyright © 2017 American Society for Microbiology.)

According to the US Food and Drug Administration and the European Food Safety Authority, amorphous forms of silica and silicates are generally recognized to be safe as oral delivery ingredients in amounts up to 1500mg per day. Silica is used in the formulation of solid dosage forms, e.g. tablets, as glidant or lubricant. The synthesis of silica-based materials depends on the payload nature, drug, macromolecule or cell, and on the target release (active or passive). In the literature, most of the examples deal with the encapsulation of drugs in mesoporous silica nanoparticles. Still to date limited reports concerning the delivery of encapsulated macromolecules and cells have been reported in the field of oral delivery, despite the multiple promising examples demonstrating the compatibility of the sol-gel route with biological entities, likewise the interest of silica as an oral carrier. Silica diatoms appear as an elegant, cost-effective and promising alternative to synthetic sol-gel-based materials. This review reports the latest advances silica-based systems and discusses the potential benefits and drawbacks of using silica for oral delivery of drugs, macromolecules or cells., (Copyright © 2017 Elsevier B.V. All rights reserved.)

As an orally administered, locally acting gastrointestinal drug, mesalamine products are designed to achieve high local drug concentration in the gastrointestinal (GI) tract for the treatment of ulcerative colitis. The aim of this study was to directly measure and compare drug dissolution of three mesalamine formulations in human GI tract and to correlate their GI concentration with drug concentration in plasma. Healthy human subjects were orally administered Pentasa, Apriso, or Lialda. GI fluids were aspirated from stomach, duodenum, proximal jejunum, mid jejunum, and distal jejunum regions. Mesalamine (5-ASA) and its primary metabolite acetyl-5-mesalamine (Ac-5-ASA) were measured using LC-MS/MS. GI tract pH was measured from each GI fluid sample, which averaged 1.82, 4.97, 5.67, 6.17, and 6.62 in the stomach, duodenum, proximal jejunum, middle jejunum, and distal jejunum, respectively. For Pentasa, high levels of 5-ASA in solution were observed in the stomach, duodenum, proximal jejunum, mid jejunum, and distal jejunum from 1 to 7 h. Apriso had minimal 5-ASA levels in stomach, low to medium levels of 5-ASA in duodenum and proximal jejunum from 4 to 7 h, and high levels of 5-ASA in distal jejunum from 3 to 7 h. In contrast, Lialda had minimal 5-ASA levels from stomach and early small intestine. A composite appearance rate (CAR) was calculated from the deconvolution of individual plasma concentration to reflect drug release, dissolution, transit, and absorption in the GI tract. Individuals dosed with Pentasa had high levels of CAR from 1 to 10 h; individuals dosed with Apriso had low levels of CAR from 1 to 4 h and high levels of CAR from 5 to 10 h; Lialda showed minimal levels of CAR from 0 to 5 h, then increased to medium levels from 5 to 12 h, and then decreased to further lower levels after 12 h. In the colon region, Pentasa and Apriso showed similar levels of accumulated 5-ASA excreted in the feces, while Lialda showed slightly higher 5-ASA accumulation in feces. However, all three formulations showed similar levels of metabolite Ac-5-ASA in the feces. These results provide direct measurement of drug dissolution in the GI tract, which can serve as a basis for investigation of bioequivalence for locally acting drug products.

Background: Absorption windows in particular segments of the small intestine can contribute to the development of orally administered drug formulations and can limit the bioavailability of released compounds., Objective: The aim of this study was to evaluate use of wireless capsule enteroscopy regarding the disintegration kinetic process of tablets in the small intestine and its comparison with the levels of the model drug (5- aminosalicylic acid; 5-ASA), and its majority metabolite (N-acetyl-5-aminosalicylic acid; N-acetyl-5-ASA) in blood plasma., Methods: Tablets were endoscopically introduced into the duodenum and their disintegration was monitored using wireless capsule enteroscopy in anaesthetised pigs. In parallel, blood plasma time profiles of the model drug (5-ASA) released from tablets and its metabolite (N-acetyl-5-ASA) were detected., Results: The disintegration of tablets was evident in the proximal jejunum (until the 90-minute mark) and culminated at the 3rd hour. The maximum plasmatic concentration of 5-ASA was reached at the 3rd hour and in the case of its metabolite (N-acetyl-5-ASA) at the 4th hour., Conclusion: The study demonstrated the advantage of combination of wireless capsule enteroscopy and bioanalytical determination of pharmacokinetic parameters in an animal experiment to localise the disintegration site of solid dosage form and following kinetics of intestinal absorption of the released active agent., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Introduction: Budesonide is a synthetic corticosteroid characterized by enhanced topical potency and limited systemic bioavailability. Its use in ulcerative colitis (UC) was limited to rectal preparations until recently when the new oral budesonide formulation incorporating the multi-matrix system technology was introduced. The purpose of this review is to evaluate the current role of oral and rectal budesonide in managing UC patients Areas covered: In this paper, we described the chemical structure and pharmacologic characteristics of the different oral and rectal budesonide preparations, provided a summary of the published trials that evaluated the efficacy and safety of budesonide in UC, and discussed the current status of its use in this population Expert opinion: Budesonide is effective in inducing remission in a subset of patients with mild-moderate UC. Nevertheless, the current evidence suggests inferiority of oral budesonide to 5-aminosalisylates (5-ASA) and systemic steroids, whereas rectal applications are comparable to other rectal steroid preparations, but still inferior to rectal 5-ASA. In clinical practice, several issues need clarification including, its exact position in the line of induction agents; the role of combining budesonide and 5-ASAs; the role of combining oral and rectal budesonide; and the role of budesonide in maintenance therapy.

Background: 5-aminosalicylic acid (5-ASA) is a classic anti-inflammatory drug for the treatment of ulcerative colitis. N-acetyltransferase (NAT) enzymes convert 5-ASA to its metabolite N-acetyl-5-ASA, and it is unresolved whether 5-ASA or N-acetyl-5-ASA is the effective therapeutic molecule. We previously demonstrated that colonic production of N-acetyl-5-ASA (NAT activity) is decreased in dextran sulfate sodium-induced colitis. Our hypothesis is that 5-ASA is the therapeutic molecule to improve colitis, with the corollary that altered NAT activity affects drug efficacy. Since varying clinical effectiveness of 5-ASA has been reported, we also ask if NAT activity varies with inflammation in pediatric or adult patients., Methods: Acute colonic inflammation was induced in C57BL/6 NAT wild-type (WT) or knockout mice, using 3.5% dextran sulfate sodium (w/v) concurrent with 5-ASA treatment. Adult and pediatric rectosigmoid biopsies were collected from control or patients with ulcerative colitis. Tissue was analyzed for NAT and myeloperoxidase activity., Results: Dextran sulfate sodium-induced colitis was of similar severity in both NAT WT and knockout mice, and NAT activity was significantly decreased in NAT WT mice. In the setting of colitis, 5-ASA significantly restored colon length and decreased myeloperoxidase activity in NAT knockout but not in WT mice. Myeloperoxidase activity negatively correlated with NAT activity in pediatric patients, but correlation was not observed in adult patients., Conclusions: Inflammation decreases NAT activity in the colon of mice and human pediatric patients. Decreased NAT activity enhances the therapeutic effect of 5-ASA in mice. A NAT activity assay could be useful to help predict the efficacy of 5-ASA therapy.

Azo-bonded prodrugs of 5-aminosalicylic acid (mesalazine)-sulfasalazine, balsalazide, and olsalazine, which are used in the treatment of ulcerative colitis, rely on colonic bacteria to cleave the azo bond and liberate the active drug in the large intestine. The aim of this study was to use an in vitro colonic simulator to determine the rates of metabolism of these three prodrugs in the presence of colonic bacteria, and to link the data to results obtained previously in humans. In individual fecal slurries prepared from five different donors, sulfasalazine degradation was rapid and virtually complete within 4 h, confirming the ubiquitous nature of azo-reduction between individuals. In pooled fecal slurry, the rate of degradation of sulfasalazine was faster (t1/2 , 32.8 min) than balsalazide (t1/2 , 80.9 min) and olsalazine (t1/2 , 145.1 min). These results are in agreement with data in humans, where it was found that sulfasalazine was more extensively metabolized on passage through the human colon than the other two drugs. These findings indicate that other than the azo bond itself, the broader chemical structure of the molecules play a role in the degradation of this class of compound, and highlight the utility of this in vitro model to evaluate the metabolism of drugs in the presence of colonic microbiota., (© 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.)

Pharmacotherapy based on 5-aminosalicylic acid (5-ASA) is a preferred treatment for ulcerative colitis, but variable patient response to this therapy is observed. Inflammation can affect therapeutic outcomes by regulating the expression and activity of drug-metabolizing enzymes; its effect on 5-ASA metabolism by the colonic arylamine N-acetyltransferase (NAT) enzyme isoforms is not firmly established. We examined if inflammation affects the capacity for colonic 5-ASA metabolism and NAT enzyme expression. 5-ASA metabolism by colonic mucosal homogenates was directly measured with a novel fluorimetric rate assay. 5-ASA metabolism reported by the assay was dependent on Ac-CoA, inhibited by alternative NAT substrates (isoniazid, p-aminobenzoylglutamate), and saturable with Km (5-ASA) = 5.8 μM. A mouse model of acute dextran sulfate sodium (DSS) colitis caused pronounced inflammation in central and distal colon, and modest inflammation of proximal colon, defined by myeloperoxidase activity and histology. DSS colitis reduced capacity for 5-ASA metabolism in central and distal colon segments by 52 and 51%, respectively. Use of selective substrates of NAT isoforms to inhibit 5-ASA metabolism suggested that mNAT2 mediated 5-ASA metabolism in normal and colitis conditions. Western blot and real-time RT-PCR identified that proximal and distal mucosa had a decreased mNAT2 protein-to-mRNA ratio after DSS. In conclusion, an acute colonic inflammation impairs the expression and function of mNAT2 enzyme, thereby diminishing the capacity for 5-ASA metabolism by colonic mucosa., (Copyright © 2014 the American Physiological Society.)

The interaction of mesalamine (5-aminosalicylic acid (5-ASA)) with bovine serum albumin (BSA) was investigated by fluorescence quenching, absorption spectroscopy, circular dichroism (CD) techniques, and molecular docking. Thermodynamic parameters (ΔH<0 and ΔS 0) indicated that the hydrogen bond and electrostatic forces played the major role in the binding of 5-ASA to BSA. The results of CD and UV-vis spectroscopy showed that the binding of this drug to BSA induces some conformational changes in BSA. Displacement experiments predicted that the binding of 5-ASA to BSA is located within domain III, Sudlows site 2, that these observations were substantiated by molecular docking studies. In addition, the docking result shows that the 5-ASA in its anionic form mainly interacts with Gln-416 residue through one hydrogen bond between H atom of 5-ASA anion and the adjacent O atom of the hydroxyl group of Gln-416., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Purpose: Few reports have compared the clinical efficacy of a pH-dependent release formulation of mesalazine (pH-5-ASA) with a time-dependent release formulation (time-5-ASA). We examined whether pH-5-ASA is effective for active ulcerative colitis (UC) in patients resistant to time-5-ASA., Methods: We retrospectively and prospectively analyzed the efficacy of pH-5-ASA in mildly to moderately active UC patients in whom time-5-ASA did not successfully induce or maintain remission. The clinical efficacy of pH-5-ASA was assessed by clinical activity index (CAI) before and after switching from time-5-ASA. In addition, the efficacy of pH-5-ASA on mucosal healing (MH) was evaluated in a prospective manner by measuring fecal calprotectin concentration., Results: Thirty patients were analyzed in a retrospective manner. CAI was significantly reduced at both 4 and 8 weeks after switching to pH-5-ASA. In the prospective study (n=14), administration of pH-5-ASA also significantly reduced CAI scores at 4 and 8 weeks in these patients who were resistant to time-5-ASA. In addition, fecal calprotectin concentration was significantly decreased along with improvement in CAI after switching to pH-5-ASA., Conclusions: Our results suggest that pH-5-ASA has clinical efficacy for mildly to moderately active patients with UC in whom time-5-ASA did not successfully induce or maintain remission.

The object of this study was to investigate the effect of probiotic Escherichia coli strain Nissle 1917 (EcN) (i) EcN lipopolysaccharide (EcN LPS) and (ii) bacteria-free supernatant of EcN suspension (EcN supernatant) on in vitro transepithelial transport of mesalazine (5-aminosalicylic acid, 5-ASA), the most commonly prescribed anti-inflammatory drug in inflammatory bowel disease (IBD). Effect of co-administered EcN LPS (100 µg/ml) or EcN supernatant (50 µg/ml) on the 5-ASA transport (300 µmol/l) was studied using the Caco-2 monolayer (a human colon carcinoma cell line) as a model of human intestinal absorption. Permeability characteristics for absorptive and secretory transport of parent drug and its intracellularly-formed metabolite were determined. The quantification of 5-ASA and its main metabolite N-acetyl-5-amino-salicylic acid (N-Ac-5-ASA) was performed by high performance liquid chromatography. Obtained results suggest that neither EcN LPS nor EcN supernatant had effect on the total 5-ASA transport (secretory flux greater than absorptive flux) and on the transport of intracellularly formed N-Ac-5-ASA (preferentially transported in the secretory direction). The percent cumulative transport of the total 5-ASA alone or in combination with EcN LPS or EcN supernatant did not exceed 1%.

The aim of the study was 1) to estimate permeability of 5-aminosalicylic acid (5-ASA), 2) to categorize 5-ASA according to BCS (Biopharmaceutics Classification System), and 3) to contribute to determination of 5-ASA transintestinal transport and biotransformation mechanisms. The in situ rat intestine perfusion was used as an initial method to study 5-ASA transport. The amount of 5-ASA (released from tablet) transferred into portal circulation reached 5.79 ± 0.24%. During this transport, the intestinal formation of 5-ASA main metabolite (N-ac-5-ASA) occurred. N-ac-5-ASA was found in perfusate both from intestinal lumen and from v. portae. In in vitro Caco-2 monolayers, transport of 5-ASA (10-1000 µmol/l) was studied in apical-basolateral and basolateral-apical direction (iso-pH 7.4 conditions). The transport of total 5-ASA (parent drug plus intracellularly formed N-ac-5-ASA) was linear with time, concentration- and direction-dependent. Higher basolateral-apical (secretory) transport was mainly caused by higher transport of the metabolite (suggesting metabolite efflux transport). Transport of 5-ASA (only parent drug) was saturable (transepithelial carrier-mediated) at low doses, dominated by passive, paracellular process in higher doses which was confirmed by increased 5-ASA transport using Ca2+-free transport medium. The estimated low 5-ASA permeability and its low solubility enable to classify 5-ASA as BCS class IV.

This paper investigates desorption of 5-aminosalicilyc acid (5-ASA) adsorbed onto halloysite (HL). Desorption isotherms were fitted according to kinetic laws obtained considering release of 5-ASA from HL as the phase of desorption of the previously adsorbed drug molecules both inside the nanotubes of HL as onto the surface of clay particles and/or in the inter-particle spaces of their aggregates. Desorption isotherms has been also fitted with other equations frequently used in drug release kinetics studies. The best fitting corresponded to the kinetic model proposed; in agreement with the results of adsorption., (Copyright © 2013 Elsevier B.V. All rights reserved.)

We present an electrical biosensing of 5-aminosalicylic acid (5-ASA) based on a peroxidase-immobilized graphene sensor on a microfluidic paper. The sensor shows a sensitive detection range from 0.5 to 20 μM and a total measuring time of 2 min with a simple fabrication procedure.

Doxorubicin (Dox) is a hydrophilic anticancer drug that has short retention time due to the efficient efflux in some cancer cells (e.g., ovarian adenocarcinoma SK-OV-3). Cyclic [W(RW)(4)] and the corresponding linear peptide (RW)(4) were conjugated with Dox through an appropriate linker to afford cyclic [W(RW)(4)]-Dox and linear (RW)(4)-Dox conjugates to enhance the cellular uptake and cellular retention of the parent drug for sustained anticancer activity. Comparative antiproliferative assays between covalent (cyclic [W(RW)(4)]-Dox and linear (RW)(4)-Dox) and the corresponding noncovalent physical mixtures of the peptides and Dox were performed. Cyclic [W(RW)(4)]-Dox inhibited the cell proliferation of human leukemia (CCRF-CEM) (62-73%), ovarian adenocarcinoma (SK-OV-3) (51-74%), colorectal carcinoma (HCT-116) (50-67%), and breast carcinoma (MDA-MB-468) (60-79%) cells at a concentration of 1 μM after 72-120 h of incubation. Cyclic [W(RW)(4)]-Dox exhibited higher antiproliferative activity than linear (RW)(4)-Dox in all cancer cells with the highest activity observed after 72 h. Flow cytometry analysis showed 3.6-fold higher cellular uptake of cyclic [W(RW)(4)]-Dox than Dox alone in SK-OV-3 cells after 24 h incubation. The cellular hydrolysis study showed that 99% of cyclic [W(RW)(4)]-Dox was hydrolyzed intracellularly within 72 h and released Dox. These data suggest that cyclic [W(RW)(4)]-Dox can be used as a potential prodrug for improving the cellular delivery and retention of Dox.

I want to break free: Mesoporous silica nanoparticles are functionalized with sulfasalazine (SZ; see scheme), a prodrug of 5-aminosalicylic acid (5-ASA) and sulfapyridine, to generate enzyme-responsive nanocarriers. In the presence of the colon-specific enzyme azo-reductase (orange), 5-ASA and sulfapyridine are efficiently released., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The objective of this study was to prepare NS-chitosan microparticles for the delivery of 5-aminosalicylic acid (5-ASA) to the colon. Microparticles can spread out over a large area of colon allowing a more effective local efficacy of 5-ASA. N-Succinyl-chitosan was chosen as carrier system because of its excellent pharmaceutical properties in colon drug targeting such as poor solubility in acid environment, biocompatibility, mucoadhesive properties, and low toxicity. It was prepared by introducing succinic group into chitosan N-terminals of the glucosamine units. 5-ASA loaded NS-chitosan microparticles were prepared using spray-drying. As a control, a matrix obtained by freeze-drying technique was also prepared and tested. Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction studies show the 5-ASA/NS-chitosan electrostatic interactions in both the systems. Mean size of the microparticles was around 5 μm, zeta potential value of both systems was always negative. Scanning electron microscopy (SEM) images show an acceptable spherical non porous structure of microparticles. In vitro swelling and drug release studies were in accordance with the polymer properties, showing the highest swelling ratio and drug release at pH=7.4 (colonic pH) where microparticles were able to deliver more than 90% of 5-ASA during 24h experiments. Rheological studies are in accordance with the swelling and release studies., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The therapeutic effects and metabolism of mesalazine (5-aminosalicylic acid) in patients with inflammatory bowel disease require intracellular accumulation of the drug in intestinal epithelial cells and hepatocytes. The molecular mechanisms of mesalazine uptake into cells have not been characterized so far. Using human embryonic kidney cells stably expressing uptake transporters of the organic anion-transporting polypeptide (OATP) family, which are expressed in human intestine and/or liver, we found that mesalazine uptake is mediated by OATP1B1, OATP1B3, and OATP2B1 but not by OATP1A2 and OATP4A1. Moreover, genetic variations (*1b, *5, *15) in the SLCO1B1 gene encoding OATP1B1 reduced the K(m) value for mesalazine uptake from 55.1 to 16.3, 24.3, and 32.4 μM, respectively, and the respective V(max) values. Finally, budesonide, cyclosporine, and rifampin were identified as inhibitors of OATP1B1-, OATP1B3-, and OATP2B1-meditated mesalazine uptake. These in vitro data indicate that OATP-mediated uptake and its modification by genetic factors and comedications may play a role for mesalazine effects.

This paper details the study of applicability of microwave initiated synthesized polyacrylamide grafted guar gum (GG-g-PAM) as matrix for controlled release of 5-amino salicylic acid (a drug used for the treatment of ulcerative colitis). In vitro release of this drug from various grades of GG-g-PAM has been studied by USP dissolution method (paddle type). The effect of percentage grafting on the rate of drug release has been investigated. The power of the microwave oven and other factors being kept constant, the percentage grafting in turn is dependent on the net time of exposure to microwave irradiation; thus a correlation can be drawn between net time of irradiation and rate of drug release (from the matrix). This holds the promise of a tailor-made matrix, with the rate of drug release being precisely programmed at the molecular level. Further, the drug release study was carried out in different pH medium, to investigate the possibility of pH triggered release for colon targeted drug delivery (where the pH is alkaline)., (Copyright 2010 Elsevier B.V. All rights reserved.)

The preparation, characterization, and in vitro release of 5-aminosalicylic acid (5-ASA) from methacrylic acid (MAA)/perlite composites (APC) prepared via a sol-gel route are reported. The free-radical graft polymerization of methacrylic acid (MAA) onto perlite particles was studied experimentally. The grafting procedure consisted of surface activation with 3-(trimethoxysilyl) propyl methacrylate (TSPA), followed by free-radical graft polymerization of methacrylic acid (MAA) in ethyl acetate with 2,2'-azobisisobutyronitrile (AIBN) initiator. The composition of the composites hybrid materials was determined by FTIR spectroscopy. Equilibrium swelling studies were carried out in enzyme-free simulated gastric and intestinal fluids (SGF and SIF, respectively). The dried composites were immersed in a saturated solution of 5-ASA in water overnight and dried over a period of three days at room temperature and the in vitro release profiles were established separately in both (SGF, pH 1) and (SIF, pH 7.4). The 5-ASA concentration of the solution was measured using a UV-Vis spectrophotometer (205 nm) at different time intervals. The in vitro drug release test revealed that the release rate of 5-ASA in buffer solutions increased with the silica content in the composites; on the contrary, the increase of the content of 3-(trimethoxysilyl)propyl methacrylate (TSPA), a coupling agent, decreased the drug release rate.

Studies to design a dry chromogenic nutrient medium for the diferentiation of Klebsiella were under way, by detecting the intracellular Klebsiella genus-specific enzyme of human potential pathogenicity--5-aminosalicylate decarboxylase. The composition of the proposed medium that ensured its high sensitivity and improved its differentiating properties as compared with the known traditional media was worked through. Klebsiella are isolated and identified on the proposed medium in one step, which substantially reduces diagnosis time and material costs and takes some burden from microbiologists.

Nitrite and nitrate are frequently used surrogate markers of nitric oxide (NO) production. Using rat models of acute and chronic DSS-induced colitis we examined the applicability of these and other NO-related metabolites, in tissues and blood, for the characterization of inflammatory bowel disease. Global NO dynamics were assessed by simultaneous quantification of nitrite, nitrate, nitroso and nitrosyl species over time in multiple compartments. NO metabolite levels were compared to a composite disease activity index (DAI) and contrasted with measurements of platelet aggregability, ascorbate redox status and the effects of 5-aminosalicylic acid (5-ASA). Nitroso products in the colon and in other organs responded in a manner consistent with the DAI. In contrast, nitrite and nitrate, in both intra- and extravascular compartments, exhibited variations that were not always in step with the DAI. Extravascular nitrite, in particular, demonstrated significant temporal instabilities, ranging from systemic drops to marked increases. The latter was particularly evident after cessation of the inflammatory stimulus and accompanied by profound ascorbate oxidation. Treatment with 5-ASA effectively reversed these fluctuations and the associated oxidative and nitrosative stress. Platelet activation was enhanced in both the acute and chronic model. Our results offer a first glimpse into the systemic nature of DSS-induced inflammation and reveal a greater complexity of NO metabolism than previously envisioned, with a clear dissociation of nitrite from other markers of NO production. The remarkable effectiveness of 5-ASA to abrogate the observed pattern of nitrite instability suggests a hitherto unrecognized role of this molecule in either development or resolution of inflammation. Its possible link to tissue oxygen consumption and the hypoxia that tends to accompany the inflammatory process warrants further investigation., ((c) 2009 Elsevier Inc. All rights reserved.)

Azoreductase 1 from Pseudomonas aeruginosa strain PAO1 (paAzoR1) catalyses the activation of the prodrug balsalazide and reduces the azo dye methyl red using reduced nicotinamide adenine dinucleotide cofactor as an electron donor. To investigate the mechanism of the enzyme, a Y131F mutation was introduced and the enzymic properties of the mutant were compared with those of the wild-type enzyme. The crystallographic structure of the mutant with methyl red bound was solved at 2.1 A resolution and compared with the wild-type structure. Tyr131 is important in the architecture of the active site but is not essential for enzymic activity.

Introduction: The pharmacokinetics and safety of Asacol (Tillotts Pharma AG, Ziefen, Switzerland), which has been used worldwide to treat ulcerative colitis and Crohn's disease, were studied in Japanese healthy male volunteers., Methods: Drug plasma concentrations and urinary and fecal excretions after a single dose (400-4800 mg) and multiple doses (3600 mg/day for 7 days) were investigated., Results: All adverse events were "not serious." The peak plasma concentration (C max) was reached at 12.3-18.0 hours after a single dose, and the C max and area under the plasma concentration-time curve (AUC) of mesalazine and its N-acetyl metabolite were proportional to the doses. The C max and AUC in non-Japanese subjects reported in the literature were closely correlated to findings in Japanese subjects, and external excretions were also similar in the Japanese and non-Japanese subjects., Conclusions: Asacol was safe and well tolerated in this Japanese population, and the non-Japanese clinical data could be extrapolated to the Japanese population.

Data from both basic research and clinical experience continue to suggest that mesalamines and thiopurines are effective and efficient for the maintenance of remission of inflammatory bowel diseases. Several decades following the formalization of their indications, attention on these two drugs has been fostered by recent achievements. Demonstration of the ability of mesalamine to activate a colonocyte differentiation factor has shed light on its chemopreventive effects on colorectal cancer; in addition to their anti-proliferative efficacy, thiopurines have been shown to be specific regulators of apoptosis. The two drugs are often co-administered in clinical practice. Recent advancements have shown that mesalamines exert a positive synergism in this context, insofar as they can inhibit side-methylation of thiopurines and hasten the function of the main immunosuppressive pathways. Considering that up to 40% of patients cannot tolerate thiopurines, such renovated targets have stimulated efforts to improve compliance by research on the toxicity mechanisms. The definition of genetic polymorphisms in the enzymes of thiopurine metabolism, and the uncovering of synergistic drug interactions, such as that with allopurinol, are just two of the results of such efforts. Interaction between basic research and clinical practice has continued to inform indications and refine the prescriptions of mesalamines and thiopurines; these have not been restrained (they have been implemented in some cases) by the advent of the novel biological molecules with anti-cytokine activity.