Systematic review: the pharmacokinetic profiles of oral mesalazine formulations and mesalazine pro-drugs used in the management of ulcerative colitis

MMX mesalamine in ulcerative colitis: Major advantages towards classical mesalamine formulations

Medical therapy is the cornerstone of ulcerative colitis (UC) management and aims to induce and maintain remission. In case of mild-to-moderate UC, mesalamine (5-ASA) is the first-line option. 5-ASA requires local release at the level of the inflamed mucosa to exert its therapeutic action. While rectal preparations are useful in distal colitis, in cases of UC of at least rectosigmoid extent, guidelines suggest the association of oral and rectal 5-ASA. Mesalamine with Multi Matrix System® technology (MMX mesalamine) is an oral, high-strength (1.2 g/tablet), once-daily formulation of 5-ASA, designed to provide delayed and prolonged release throughout the entire colon. Clinical trials demonstrated a strong efficacy in inducing and maintaining clinical and endoscopic remission in active mild-to-moderate UC. The efficacy is related to specific colonic drug-delivery, to its high-dosage and once-daily administration, thus improving patients' adherence and outcomes. The specific colonic-delivery is also associated with very low rates of systemic absorption and adverse events (AEs). With this comprehensive review we aimed to summarize current knowledge on MMX mesalamine in mild-to-moderate UC, in terms of clinical pharmacology, efficacy and safety, also compared to other 5-ASA products. In addition we provided an expert opinion on the topic, examining the implications on clinical practice.

Sodium orthovanadate protects against ulcerative colitis and associated liver damage in mice: insights into modulations of Nrf2/Keap1 and NF-κB pathways

Ulcerative colitis (UC) is a prominent category of disease that is associated with bowel inflammation, it can occur at any period of life and is prevalently rising on a global scale. Dextran sulfate sodium (DSS) has been extensively used to develop colitis due to its ability to mimic human UC, providing consistent and reproducible inflammation, ulceration, and disruption of the epithelial barrier in the colon. Chronic inflammation in the gut can lead to alterations in the gut-liver axis, potentially impacting liver function over time, while direct evidence linking diversion colitis to liver damage is limited. Thus, the present study aims to assess the gut and liver damage against DSS and the possible molecular mechanisms. Forty-seven animals were randomly assigned to six groups. Ulcerative colitis was induced using 2.5% w/v DSS in three alternate cycles, each lasting 7 days, with 1-week remission periods in between. SOV (5 and 10 mg/kg, orally) and the standard drug 5-aminosalicylic acid (100 mg/kg, orally) were administered from the start of the 2nd DSS cycle until the end of the experiment. Biochemical parameters, ELISA, histopathological, and immunohistochemical analyses have been conducted to assess damage in the colon and liver. SOV significantly reduced colitis severity by lowering the DAI score, oxidative stress markers (LPS, IL-1β, MPO, nitrite), and restoring liver biomarkers (SGPT, SGOT). Histopathological findings supported these protective benefits in the liver and gut. Moreover, immunohistochemical analysis showed SOV enhanced the expression of the cytoprotective mediator Nrf2/Keap-1 and reduced the expression of inflammatory mediators NF-κB and IL-6. Present findings concluded that SOV demonstrated a dose-dependent effect against UC through anti-inflammatory and antioxidant pathways, with the highest dose of SOV 10 mg/kg having more significant (p < 0.001) results than the low dose of 5 mg/kg.

Water-Soluble Se-Containing Proteins from Chicken Alleviate DSS-Induced Ulcerative Colitis in Mice via Inhibiting TLR4/MyD88 Pathway and Protecting the Goblet Cell Pathway

The influence of water-soluble selenium-containing proteins (WSSeP) in chicken on ulcerative colitis (UC) is not known. This work aims to investigate the effect of two WSSeP including h-Se with 1.78 μg Se/g and l-Se with 1.04 μg Se/g on mice UC induced by dextran sodium sulfate (DSS) versus 5-aminosalicylic acid (5-ASA). Seventy C57BL/6 mice were randomly divided into seven groups: groups 1 and 7 were given normal saline. Group 2 to group 4 were administrated orally 500, 1500, and 3000 mg/kg/day h-Se, respectively. Group 5 was given 1500 mg/kg/day l-Se as the control of group 3. From day 14 to day 21, groups 2 to 7 were fed with 3% DSS. Synchronously, group 6 was fed with 150 mg/kg/day 5-ASA. On day 21, the disease activity index, colon length, the histopathological changes, the expressions of claudin-1, occludin, ZO-1, TLR4, and MyD88 in colons, the levels of inflammatory cytokines (IFN-γ, IL-1β, IL-6, TNF-α), and antioxidant markers (LPS, GSH-Px, SOD, MDA) in serum were determined. WSSeP can effectively improve the damages of DSS to the colon, thymus, and spleen, which present protein and Se dose-dependent. 1.50 g h-Se dose can significantly promote the expression levels of claudin-1, occludin, and ZO-1, to surround crypt gland and goblet and epithelial cells and inhibit the attack of DSS, suppress TLR4/MyD88 pathway, decrease the levels of IL-1β, IL-6, TNF-α, IFN-γ, LPS, and MDA, and increase the activities of GSH-Px and SOD, which are better than those of 5-ASA. Therefore, WSSeP would be a natural and potential anti-inflammatory agent for UC.

Oral Formulation of 5-Aminosalicylic Acid-Hemoglobin Bio-Adhesive Nanoparticles Enhance Therapeutic Efficiency in Ulcerative Colitis Mice: A Preclinical Evaluation

The oral formulation design for colon-specific drug delivery brings some therapeutic benefits in the ulcerative colitis treatment. We recently reported the specific delivery of hemoglobin nanoparticles-conjugating 5-aminosalicylic acid (5-ASA-HbNPs) to the inflamed site. In the current study, the therapeutic effect of the 5-ASA-HbNPs formulation was confirmed in vivo. This evaluation of 5-ASA-HbNPs not only shows longer colonic retention time due to adhesive properties, also provides full support for it as compared with free 5-ASA. It was considered as a suitable bio-adhesive nanoparticle with mucoadhesive property to pass through the mucus layer and accumulate into the mucosa. In UC model mice, a two-fold decrease in the disease activity indexes and colon weight/length ratios was significantly observed in the group treated with 5-ASA-HbNPs. This group received one percent of the standard dosage of 5-ASA (50 μg/kg), while, a similar result was observed for a significant amount of free 5-ASA (5 mg/kg). Furthermore, microscopic images of histological sections of the extracted colons demonstrated that the 5-ASA-HbNPs and 5-ASA groups displayed instances of inflammatory damage within the colon. However, in comparison to the colitis group, the extent of this damage was relatively moderate, suggesting 5-ASA-HbNPs improved therapeutic efficacy with the lower dosage form.

Interaction of sulfasalazine with outer surface of boron-nitride nanotube as a drug carrier in aqueous solution: insights from quantum mechanics and Monte Carlo simulation

The improvement of the solubility of sulfasalazine in physiological media was the major aim of this study. Accordingly, BNNT inspected as a notable candidate for the carriage of this drug in aqueous media. For this purpose, four possible interactions of two tautomer of sulfasalazine with (9,0) boron-nitride nanotube were considered in aqueous media. The compounds were optimized in gas phase using density functional calculations. Solvation free energies and association free energies of the optimized structures were then studied by Monte Carlo simulation and perturbation method in water environment. Outcomes of quantum mechanical calculations presented that interaction of keto form of sulfasalazine produce the most stable complexes with boron-nitride nanotube in gas phase. Simulation results revealed that electrostatic interactions play a vital role in the intermolecular interaction energies after binding of drug and nanotube in aqueous solution. Results of association free energy calculations indicated that complexes of both two sulfasalazine tautomers (keto and enol) and nanotube were stable in solution. Computed solvation free energies in water showed that the interaction with boron-nitride nanotube significantly improved the solubility of sulfasalazine, which could improve its in vivo bioavailability.

The cyclooxygenase-expressing mesenchyme resists intestinal epithelial injury by paracrine signaling

Paracrine signals play pivotal roles in organ homeostasis. Mesenchymal stromal cells (MSCs) play a key role in regulating epithelium homeostasis in the intestine while their paracrine effects are poorly characterized. Here, we identified prostaglandin E2 (PGE2) secreted by cyclooxygenase (COX)-expressing MSCs as a vital factor to maintain the intestinal mucosal barrier. We found that MSCs-induced organoid swelling through paracrine effect in vitro, a process due to enhanced water adsorption and is mediated by the COX-PGE2-EP4 axis. To further explore the regulatory effect of this axis on the intestinal epithelial barrier in vivo, we established the conditional knockout mouse model to specifically delete COX in MSCs and found that PGE2 reduction downregulated the gene Muc2 and induced a gastric metaplasia-like phenotype. Moreover, PGE2 defects increased the susceptibility of intestinal epithelium to colitis. Our study uncovers the paracrine signaling of COX-expressing MSCs in intestinal mucosal barrier maintenance, providing a basis for understanding the role of mesenchymal cells in the pathophysiological function of the intestine.

Ulcerative colitis

Ulcerative colitis is a lifelong inflammatory disease affecting the rectum and colon to a variable extent. In 2023, the prevalence of ulcerative colitis was estimated to be 5 million cases around the world, and the incidence is increasing worldwide. Ulcerative colitis is thought to occur in people with a genetic predisposition following environmental exposures; gut epithelial barrier defects, the microbiota, and a dysregulated immune response are strongly implicated. Patients usually present with bloody diarrhoea, and the diagnosis is based on a combination of clinical, biological, endoscopic, and histological findings. The aim of medical management is, first, to induce a rapid clinical response and normalise biomarkers and, second, to maintain clinical remission and reach endoscopic normalisation to prevent long-term disability. Treatments for inducing remission include 5-aminosalicylic acid drugs and corticosteroids. Maintenance treatments include 5-aminosalicylic acid drugs, thiopurines, biologics (eg, anti-cytokines and anti-integrins), and small molecules (Janus kinase inhibitors and sphingosine-1-phosphate receptor modulators). Although the therapeutic options are expanding, 10-20% of patients still require proctocolectomy for medically refractory disease. The keys to breaking through this therapeutic ceiling might be the combination of therapeutics with precision and personalised medicine.

Influence of Different Diets on the Degradation of Sulfasalazine by Colon Bacteria Determined Using MimiCol3

The microbiome of the colon is characterized by its great diversity. This varies not only intra- but also interindividually and is influenced by endogenous and exogenous factors, such as dietary and lifestyle factors. The aim of this work was to investigate the extent to which the degradation of the drug sulfasalazine is influenced by different microbiota. Therefore, the in vitro model MimiCol3 was used, which represents the physiological conditions of the ascending colon. In addition to a representative physiological volume, the pH value, redox potential and an anaerobic atmosphere are important to provide the bacteria with the best possible growth conditions. Stool samples were taken from three healthy subjects, comparing omnivorous, vegetarian and meat-rich diets, and cultured for 24 h. However, the nutrient medium used for cultivation led to the alignment of the bacterial composition of the microbiota. The previously observed differences between the diets could not be maintained. Nevertheless, the similar degradation of sulfasalazine was observed in all microbiota studied in MimiCol3. This makes MimiCol3 a suitable in vitro model for metabolism studies in the gut microbiome.

Lafoensia pacari alleviates intestinal damage by modulating cyclooxygenase-2: In silico and in vivo evaluation in a colitis model

BACKGROUND

Inflammatory bowel diseases (IBD) are a worldwide health problem and mainly affect young people, consequently affecting the workforce. Available treatments are often associated with side effects, and new therapeutic options are needed. For centuries, plants have represented important substrates in the field of drug development. Lafoensia pacari (L. pacari) is a plant whose pharmaceutical potential has been described, and may have biological activity relevant to the treatment of IBD symptoms.

AIM

To investigate the activity of keto-alcoholic extracts of L. pacari with respect to ameliorating the inflammatory and nociceptive symptoms of acute experimental colitis in mice.

METHODS

Keto-alcoholic extracts of L. pacari leaves and bark were administered to male and female Swiss mice weighing 25 g to 30 g (n = 8 male mice and n = 8 female mice). The effect of these extracts was observed in an acetic acid-induced acute experimental model of colitis with regard to antinociception/analgesia and inflammatory tissue damage. Recorded macroscopic indices included the Wallace score and the colon weight obtained using a precision scale. Mechanical hyperalgesia was determined using an electronic analgesimeter. Behavior related to overt pain was determined by quantifying the number of writhing instances within 20 min of administration of acetic acid. Molecular docking was performed using human and murine cyclooxygenase-2 (COX-2) with 3 flavonoids (ellagic acid, kaempferol, and quercetin) on the AutoDock Vina software. Analysis of variance followed by Tukey’s posttest was used with P < 0.05 indicating significance.

RESULTS

In this murine model of colitis, administration of extracts from L. pacari ameliorated acetic acid-induced writhing and colitis-associated inflammatory pain. These improvements may be attributable to the reduction in edema, inflammation (e.g., ulcers, hyperemia, and bowel wall damage), and the intensity of abdominal hyperalgesia. The keto-alcoholic extracts of L. pacari leaves and bark administered at a dose of either 100 mg/kg or 300 mg/kg significantly reduced the number of writhing events when compared to the negative control (P < 0.05). Additionally, extracts of L. pacari bark also performed better than Dipyrone. Leaf extracts administered at 10 mg/kg, 30 mg/kg, and 100 mg/kg and bark extracts administered at 30 mg/kg significantly reduced or prevented the development of edema in the colon of treated mice, while mesalazine did not. Moreover, using molecular docking, we observed that the flavonoids present in L. pacari extracts bind to COX-2, an event not unique to ellagic acid.

CONCLUSION

The results of this study demonstrate a potential novel application of L. pacari extracts for the reduction of inflammation and promotion of antinociception/analgesia as demonstrated by our findings in a murine model of colitis. These findings were also corroborated by in silico analyses, and suggest that L. pacari extracts may be a promising therapeutic agent in the treatment of IBD.

Gut microbial metabolism of 5-ASA diminishes its clinical efficacy in inflammatory bowel disease

For decades, variability in clinical efficacy of the widely used inflammatory bowel disease (IBD) drug 5-aminosalicylic acid (5-ASA) has been attributed, in part, to its acetylation and inactivation by gut microbes. Identification of the responsible microbes and enzyme(s), however, has proved elusive. To uncover the source of this metabolism, we developed a multi-omics workflow combining gut microbiome metagenomics, metatranscriptomics and metabolomics from the longitudinal IBDMDB cohort of 132 controls and patients with IBD. This associated 12 previously uncharacterized microbial acetyltransferases with 5-ASA inactivation, belonging to two protein superfamilies: thiolases and acyl-CoA N-acyltransferases. In vitro characterization of representatives from both families confirmed the ability of these enzymes to acetylate 5-ASA. A cross-sectional analysis within the discovery cohort and subsequent prospective validation within the independent SPARC IBD cohort (n = 208) found three of these microbial thiolases and one acyl-CoA N-acyltransferase to be epidemiologically associated with an increased risk of treatment failure among 5-ASA users. Together, these data address a longstanding challenge in IBD management, outline a method for the discovery of previously uncharacterized gut microbial activities and advance the possibility of microbiome-based personalized medicine.

Bioadhesive Tannic-Acid-Functionalized Zein Coating Achieves Engineered Colonic Delivery of IBD Therapeutics via Reservoir Microdevices

The biggest challenge in oral delivery of anti-inflammatory drugs such as 5-aminosalicylic acid (5-ASA) is to (i) prevent rapid absorption in the small intestine and (ii) achieve localized release at the site of inflammation in the lower gut, i.e., the colon. Here, we present an advanced biopolymeric coating comprising of tannic-acid-functionalized zein protein to provide a sustained, colon-targeted release profile for 5-ASA and enhance the mucoadhesion of the dosage form via a mussel-inspired mechanism. To enable localized delivery and provide high local concentration, 5-ASA is loaded into the microfabricated drug carriers (microcontainers) and sealed with the developed coating. The functionality and drug release profile of the coating are characterized and optimized in vitro, showing great tunability, scalability, and stability toward proteases. Further, ex vivo experiments demonstrate that the tannic acid functionalization can significantly enhance the mucoadhesion of the coating, which is followed up by in vivo investigations on the intestinal retention, and pharmacokinetic evaluation of the 5-ASA delivery system. Results indicate that the developed coating can provide prolonged colonic delivery of 5-ASA. Therefore, the here-developed biodegradable coating can be an eco-friendly substitute to the state-of-the-art commercial counterparts for targeted delivery of 5-ASA and other small molecule drugs.

An Advanced Bioreactor Simulating Dynamic Physiological Conditions in the Human Ascending Colon: MimiCol3

In recent years, the colon has become a hot topic in biopharmaceutical research as several in vitro models of the human colon have been presented. A major focus is on the characterization of the microbiota and its capabilities. The aim of the present study was to further develop the MimiCol, preserving its properties and accelerating data acquisition. Emphasis was placed on the simplicity of its design and easy scalability. To prove the viability of the concept, degradation of sulfasalazine was investigated, and the bacterial composition during the experiment was assessed by 16S rRNA sequencing. The transfer of the experimental conditions to the new model was successful. Commercially available components were implemented in the setup. The model MimiCol³ represented the colon ascendens satisfactorily in its properties regarding volume, pH value, and redox potential. 16S rRNA sequencing led to further insights into the bacterial composition in the vessels. Degradation of sulfasalazine was in good agreement with in vivo data. The new model of the colon ascendens MimiCol³ enabled us to collect more reliable data, as three experiments were conducted simultaneously under the same conditions.

The effect of esomeprazole on the upper GI tract release and systemic absorption of mesalazine from colon targeted formulations

The aim of the present study was to investigate the effect of coadministration of the proton pump inhibitor (PPI) esomeprazole on the upper GI tract behavior and systemic exposure of mesalazine from two mechanistically different colon targeted delivery systems: Claversal (pH-dependent release) and Pentasa (prolonged release). To this end, gastric, jejunal and systemic concentrations of mesalazine and its metabolite N-acetyl mesalazine were monitored in 5 healthy volunteers following oral intake of Pentasa or Claversal with or without PPI pre-treatment (cross-over study). Our exploratory study demonstrated that pre-treatment with a PPI may affect the release and absorption of mesalazine from formulations with different modified release mechanisms. Upon intake of Claversal, the onset of mesalazine absorption was accelerated substantially by PPI pre-treatment. While the PPI-induced increase in pH initiated the disintegration process already in the upper GI tract, the release of mesalazine started beyond the proximal jejunum. Upon intake of Pentasa, PPI pre-treatment seemed to increase the systemic exposure, even though the underlying mechanism could not be revealed yet. The faster release of mesalazine in the GI tract and/or the increased systemic absorption following PPI pre-treatment may reduce the ability of mesalazine to reach the colon. Future research assessing mesalazine disposition in the lower GI tract is warranted.

Gut Microbiota Metabolism of Azathioprine: A New Hallmark for Personalized Drug-Targeted Therapy of Chronic Inflammatory Bowel Disease

Despite the growing number of new drugs approved for the treatment of inflammatory bowel disease (IBD), the long-term clinical use of thiopurine therapy and the well-known properties of conventional drugs including azathioprine have made their place in IBD therapy extremely valuable. Despite the fact that thiopurine S-methyltransferase (TPMT) polymorphism has been recognized as a major cause of the interindividual variability in the azathioprine response, recent evidence suggests that there might be some yet unknown causes which complicate dosing strategies causing either failure of therapy or toxicity. Increasing evidence suggests that gut microbiota, with its ability to release microbial enzymes, affects the pharmacokinetics of numerous drugs and subsequently drastically alters clinical effectiveness. Azathioprine, as an orally administered drug which has a complex metabolic pathway, is the prime illustrative candidate for such microbial metabolism of drugs. Comprehensive databases on microbial drug-metabolizing enzymes have not yet been generated. This study provides insights into the current evidence on microbiota-mediated metabolism of azathioprine and systematically accumulates findings of bacteria that possess enzymes required for the azathioprine biotransformation. Additionally, it proposes concepts for the identification of gut bacteria species responsible for the metabolism of azathioprine that could aid in the prediction of dose-response effects, complementing pharmacogenetic approaches already applied in the optimization of thiopurine therapy of IBD. It would be of great importance to elucidate to what extent microbiota-mediated metabolism of azathioprine contributes to the drug outcomes in IBD patients which could facilitate the clinical implementation of novel tools for personalized thiopurine treatment of IBD.

Development and validation of HPLC-DAD and LC-(ESI)/MS methods for the determination of sulfasalazine, mesalazine and hydrocortisone 21-acetate in tablets and rectal suppositories: In vitro and ex vivo permeability studies

Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-acetate (HA) were prepared as recommended dosage forms for the treatment of acute episodes of ulcerative colitis, in patients who do not respond to monotherapy. A High-Performance Liquid Chromatography (HPLC) Diode-array method with a gradient elution mobile phase was developed to evaluate the production quality of both formulations (assay and dissolution profiles in gastric and intestinal fluids). Method's validation was carried out providing good linearity (r ≥ 0.9995), precision (RSD < 1.53%), recovery (96.9% - 103.7%) and limits of detection (LOD_SLF = 12 ng/mL, LOD_HA = 15 ng/mL). Experimental design and Plackett-Burman methodology was constructed to study the robustness of the analysis. In all composite substrates, a freezing lipid precipitation approach was used as purification step. The method was optimized by applying Central Composite design mode. The in-vitro/ex-vivo permeability studies of both formulations were evaluated by a Liquid Chromatography-Electron Spray Ionization Mass Spectrometry (LC-ESI/MS) +/- mode. The analysis of sulfamethazine (internal standard, SLM, m/z 279), HA (m/z 449, [M + HCOO]^-), SLF (m/z 399) and its active metabolite mesalazine (MSL, m/z 154) was performed using a C₁₈ column and gradient elution. The validation of the method met the requirements of the International Council for Harmonization (ICH) (r ≥ 0.9997, RSD ≤ 4.62%, Recovery > 95%, LOD_SLF = 1.28 ng/mL, LOD_HA = 1.07 ng/mL, LOD_MSL = 3.16 ng/mL). Based on the results, important conclusions were drawn concerning the role of excipients and SLF metabolism.

Dapsone Azo-Linked with Two Mesalazine Moieties Is a "Me-Better" Alternative to Sulfasalazine

Dapsone (DpS) is an antimicrobial and antiprotozoal agent, especially used to treat leprosy. The drug shares a similar mode of action with sulfonamides. Additionally, it possesses anti-inflammatory activity, useful for treating autoimmune diseases. Here, we developed a “me-better” alternative to sulfasalazine (SSZ), a colon-specific prodrug of mesalazine (5-ASA) used as an anti-inflammatory bowel diseases drug; DpS azo-linked with two molecules of 5-ASA (AS-DpS-AS) was designed and synthesized, and its colon specificity and anti-colitic activity were evaluated. AS-DpS-AS was converted to DpS and the two molecules of 5-ASA (up to approximately 87% conversion) within 24 h after incubation in the cecal contents. Compared to SSZ, AS-DpS-AS showed greater efficiency in colonic drug delivery following oral gavage. Simultaneously, AS-DpS-AS substantially limited the systemic absorption of DpS. In a dinitrobenzene sulfonic acid-induced rat colitis model, oral AS-DpS-AS elicited better efficacy against rat colitis than oral SSZ. Moreover, intracolonic treatment with DpS and/or 5-ASA clearly showed that combined treatment with DpS and 5-ASA was more effective against rat colitis than the single treatment with either DpS or 5-ASA. These results suggest that AS-DpS-AS may be a “me-better” drug of SSZ with higher therapeutic efficacy, owing to the combined anti-colitic effects of 5-ASA and DpS.

Differential effects of mesalazine formulations on thiopurine metabolism through thiopurine S-methyltransferase inhibition

BACKGROUND AND AIM

Thiopurines are often used in combination with mesalazine for the treatment of ulcerative colitis (UC). Mesalazine formulations are delivered to the digestive tract by various delivery systems and absorbed as 5-aminosalicylic acid (5-ASA). 5-ASA is known to inhibit thiopurine S-methyltransferase (TPMT) activity and to affect thiopurine metabolism. There have been no studies comparing TPMT inhibition by multimatrix mesalazine (MMX) with other formulations. We investigated the difference in TPMT inhibition by different mesalazine formulations and prospectively confirmed the clinical relevance.

METHODS

Plasma concentrations of 5-ASA, N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA), and TPMT activities were measured in UC patients receiving various mesalazine formulations (time-dependent or pH-dependent mesalazine or MMX) as monotherapy. Patients already on both time-dependent or pH-dependent mesalazine and thiopurines switched their mesalazine to MMX, examining 6-thioguanine nucleotide (6-TGN) and 6-methylmercaptopurine (6-MMP) 0 and 8 weeks after switching. Clinical relapse after switching was also monitored for 24 weeks.

RESULTS

Plasma 5-ASA and N-Ac-5-ASA levels were significantly higher in patients receiving time-dependent mesalazine (n = 12) compared with pH-dependent mesalazine (n = 12) and MMX (n = 15), accompanied by greater TPMT inhibition. Prospective switching from time-dependent mesalazine to MMX decreased 6-TGN levels, increased those of 6-MMP, and increased 6-MMP/6-TGN ratios. Furthermore, this resulted in significantly more relapses than switching from pH-dependent mesalazine to MMX.

CONCLUSIONS

Time-dependent mesalazine has higher plasma 5-ASA and N-Ac-5-ASA levels and greater TPMT inhibition than MMX. Therefore, switching from time-dependent mesalazine to MMX may lead to an increase of 6-MMP/6-TGN, which may reduce the clinical effectiveness of thiopurines, warranting close monitoring after switch.

Multicenter survey on mesalamine intolerance in patients with ulcerative colitis

BACKGROUND AND AIM

Although oral mesalamine is the first-choice drug for treating mild-to-moderate ulcerative colitis (UC), some patients show symptoms of intolerance, including exacerbation of diarrhea and abdominal pain. The present study clarified the current state and clinical courses of patients with mesalamine intolerance.

METHODS

Patients who were diagnosed with UC and administered oral mesalamine at eight hospitals in Japan with a follow-up period exceeding 1 year were analyzed.

RESULTS

Sixty-seven (11%) of 633 patients showed intolerance to at least one formulation of oral mesalamine. The frequency of mesalamine intolerance has increased in recent years, rising from 5.3% in 2007-2010 to 9.1% in 2011-2013 and 16.2% in 2014-2016. The most common complications were the exacerbation of diarrhea (n = 29), a fever (n = 25), and abdominal pain (n = 22). Readministration of mesalamine/sulfasalazine was attempted in 43 patients, mostly with other types of formulation of mesalamine, and more than half of these patients proved to be tolerant. The risk factors for mesalamine intolerance were female gender (odds ratio [OR] = 1.83; 95% confidence interval [CI], 1.08-3.12), age < 60 years old (OR = 2.82; CI, 1.19-8.33), and pancolitis (OR = 2.09; 95% CI, 1.23-3.60). There were no significant differences in the use of anti-tumor necrosis factor-α agents, colectomy, or steroid-free remission at the last visit between patients with and without mesalamine intolerance.

CONCLUSIONS

Mesalamine intolerance is not rare, and its frequency has been increasing recently. The prognosis of patients with mesalamine intolerance did not differ significantly from that of those without intolerance.

A disposable electrode modified with metal orthovanadate and sulfur-reduced graphene oxide for electrochemical detection of

CVO@SRG composite was prepared by a hydrothermal method and the voltammetric measurement of an organic compound.

Oral 5-aminosalicylic acid for maintenance of remission in ulcerative colitis

BACKGROUND

Oral 5-aminosalicylic acid (5-ASA; also known as mesalazine or mesalamine) preparations were intended to avoid the adverse effects of sulfasalazine (SASP) while maintaining its therapeutic benefits. In an earlier version of this review, we found that 5-ASA drugs were more effective than placebo for maintenance of remission of ulcerative colitis (UC), but had a significant therapeutic inferiority relative to SASP. In this version, we have rerun the search to bring the review up to date.

OBJECTIVES

To assess the efficacy, dose-responsiveness, and safety of oral 5-ASA compared to placebo, SASP, or 5-ASA comparators for maintenance of remission in quiescent UC and to compare the efficacy and safety of once-daily dosing of oral 5-ASA with conventional (two or three times daily) dosing regimens.

SEARCH METHODS

We performed a literature search for studies on 11 June 2019 using MEDLINE, Embase, and the Cochrane Library. In addition, we searched review articles and conference proceedings.

SELECTION CRITERIA

We included randomized controlled trials with a minimum treatment duration of six months. We considered studies of oral 5-ASA therapy for treatment of participants with quiescent UC compared with placebo, SASP, or other 5-ASA formulations. We also included studies that compared once-daily 5-ASA treatment with conventional dosing of 5-ASA and 5-ASA dose-ranging studies.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. The primary outcome was the failure to maintain clinical or endoscopic remission. Secondary outcomes were adherence, adverse events (AE), serious adverse events (SAE), withdrawals due to AEs, and withdrawals or exclusions after entry. Trials were separated into five comparison groups: 5-ASA versus placebo, 5-ASA versus SASP, once-daily dosing versus conventional dosing, 5-ASA (balsalazide, Pentasa, and olsalazine) versus comparator 5-ASA formulation (Asacol and Salofalk), and 5-ASA dose-ranging. We calculated the risk ratio (RR) and 95% confidence interval (CI) for each outcome. We analyzed data on an intention-to-treat basis, and used GRADE to assess the overall certainty of the evidence.

MAIN RESULTS

The search identified 44 studies (9967 participants). Most studies were at low risk of bias. Ten studies were at high risk of bias. Seven of these studies were single-blind and three were open-label. 5-ASA is more effective than placebo for maintenance of clinical or endoscopic remission. About 37% (335/907) of 5-ASA participants relapsed at six to 12 months compared to 55% (355/648) of placebo participants (RR 0.68, 95% CI 0.61 to 0.76; 8 studies, 1555 participants; high-certainty evidence). Adherence to study medication was not reported for this comparison. SAEs were reported in 1% (6/550) of participants in the 5-ASA group compared to 2% (5/276) of participants in the placebo group at six to 12 months (RR 0.60, 95% CI 0.19 to 1.84; 3 studies, 826 participants; low-certainty evidence). There is probably little or no difference in AEs at six to 12 months' follow-up (RR 0.93, 95% CI 0.73 to 1.18; 5 studies, 1132 participants; moderate-certainty evidence). SASP is more effective than 5-ASA for maintenance of remission. About 48% (416/871) of 5-ASA participants relapsed at six to 18 months compared to 43% (336/784) of SASP participants (RR 1.14, 95% CI 1.03 to 1.27; 12 studies, 1655 participants; high-certainty evidence). Adherence to study medication and SAEs were not reported for this comparison. There is probably little or no difference in AEs at six to 12 months' follow-up (RR 1.07, 95% CI 0.82 to 1.40; 7 studies, 1138 participants; moderate-certainty evidence). There is little or no difference in clinical or endoscopic remission rates between once-daily and conventionally dosed 5-ASA. About 37% (717/1939) of once-daily participants relapsed over 12 months compared to 39% (770/1971) of conventional-dosing participants (RR 0.94, 95% CI 0.88 to 1.01; 10 studies, 3910 participants; high-certainty evidence). There is probably little or no difference in medication adherence rates. About 10% (106/1152) of participants in the once-daily group failed to adhere to their medication regimen compared to 8% (84/1154) of participants in the conventional-dosing group (RR 1.18, 95% CI 0.72 to 1.93; 9 studies, 2306 participants; moderate-certainty evidence). About 3% (41/1587) of participants in the once-daily group experienced a SAE compared to 2% (35/1609) of participants in the conventional-dose group at six to 12 months (RR 1.20, 95% CI 0.77 to 1.87; moderate-certainty evidence). There is little or no difference in the incidence of AEs at six to 13 months' follow-up (RR 0.98, 95% CI 0.92 to 1.04; 8 studies, 3497 participants; high-certainty evidence). There may be little or no difference in the efficacy of different 5-ASA formulations. About 44% (158/358) of participants in the 5-ASA group relapsed at six to 18 months compared to 41% (142/349) of participants in the 5-ASA comparator group (RR 1.08, 95% CI 0.91 to 1.28; 6 studies, 707 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that 5-ASA is superior to placebo for maintenance therapy in UC. There is high-certainty evidence that 5-ASA is inferior compared to SASP. There is probably little or no difference between 5-ASA and placebo, and 5-ASA and SASP in commonly reported AEs such as flatulence, abdominal pain, nausea, diarrhea, headache, and dyspepsia. Oral 5-ASA administered once daily has a similar benefit and harm profile as conventional dosing for maintenance of remission in quiescent UC.

Oral 5-aminosalicylic acid for induction of remission in ulcerative colitis

BACKGROUND

Oral 5-aminosalicylic acid (5-ASA) preparations were intended to avoid the adverse effects of sulfasalazine (SASP) while maintaining its therapeutic benefits. It was previously found that 5-ASA drugs in doses of at least 2 g/day were more effective than placebo but no more effective than SASP for inducing remission in ulcerative colitis (UC). This review is an update of a previously published Cochrane Review.

OBJECTIVES

To assess the efficacy, dose-responsiveness and safety of oral 5-ASA compared to placebo, SASP, or 5-ASA comparators (i.e. other formulations of 5-ASA) for induction of remission in active UC. A secondary objective was to compare the efficacy and safety of once-daily dosing of oral 5-ASA versus conventional dosing regimens (two or three times daily).

SEARCH METHODS

We searched MEDLINE, Embase and the Cochrane Library on 11 June 2019. We also searched references, conference proceedings and study registers to identify additional studies.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) including adults (aged 18 years or more) with active UC for inclusion. We included studies that compared oral 5-ASA therapy with placebo, SASP, or other 5-ASA formulations. We also included studies that compared once-daily to conventional dosing as well as dose-ranging studies.

DATA COLLECTION AND ANALYSIS

Outcomes include failure to induce global/clinical remission, global/clinical improvement, endoscopic remission, endoscopic improvement, adherence, adverse events (AEs), serious adverse events (SAEs), withdrawals due to AEs, and withdrawals or exclusions after entry. We analyzed five comparisons: 5-ASA versus placebo, 5-ASA versus sulfasalazine, once-daily dosing versus conventional dosing, 5-ASA (e.g. MMX mesalamine, Ipocol, Balsalazide, Pentasa, Olsalazine and 5-ASA micropellets) versus comparator 5-ASA (e.g. Asacol, Claversal, Salofalk), and 5-ASA dose-ranging. We calculated the risk ratio (RR) and 95% confidence interval (95% CI) for each outcome. We analyzed data on an intention-to-treat basis, and used GRADE to assess the overall certainty of the evidence.

MAIN RESULTS

We include 54 studies (9612 participants). We rated most studies at low risk of bias. Seventy-one per cent (1107/1550) of 5-ASA participants failed to enter clinical remission compared to 83% (695/837) of placebo participants (RR 0.86, 95% CI 0.82 to 0.89; 2387 participants, 11 studies; high-certainty evidence). We also observed a dose-response trend for 5-ASA. There was no difference in clinical remission rates between 5-ASA and SASP. Fifty-four per cent (150/279) of 5-ASA participants failed to enter remission compared to 58% (144/247) of SASP participants (RR 0.90, 95% CI 0.77 to 1.04; 526 participants, 8 studies; moderate-certainty evidence). There was no difference in remission rates between once-daily dosing and conventional dosing. Sixty per cent (533/881) of once-daily participants failed to enter clinical remission compared to 61% (538/880) of conventionally-dosed participants (RR 0.99, 95% CI 0.93 to 1.06; 1761 participants, 5 studies; high-certainty evidence). Eight per cent (15/179) of participants dosed once daily failed to adhere to their medication regimen compared to 6% (11/179) of conventionally-dosed participants (RR 1.36, 95% CI 0.64 to 2.86; 358 participants, 2 studies; low-certainty evidence). There does not appear to be any difference in efficacy among the various 5-ASA formulations. Fifty per cent (507/1022) of participants in the 5-ASA group failed to enter remission compared to 52% (491/946) of participants in the 5-ASA comparator group (RR 0.94, 95% CI 0.86 to 1.02; 1968 participants, 11 studies; moderate-certainty evidence). There was no evidence of a difference in the incidence of adverse events and serious adverse events between 5-ASA and placebo, once-daily and conventionally-dosed 5-ASA, and 5-ASA and comparator 5-ASA formulation studies. Common adverse events included flatulence, abdominal pain, nausea, diarrhea, headache and worsening UC. SASP was not as well tolerated as 5-ASA. Twenty-nine per cent (118/411) of SASP participants experienced an AE compared to 15% (72/498) of 5-ASA participants (RR 0.48, 95% CI 0.36 to 0.63; 909 participants, 12 studies; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

There is high-certainty evidence that 5-ASA is superior to placebo, and moderate-certainty evidence that 5-ASA is not more effective than SASP. Considering relative costs, a clinical advantage to using oral 5-ASA in place of SASP appears unlikely. High-certainty evidence suggests 5-ASA dosed once daily appears to be as efficacious as conventionally-dosed 5-ASA. There may be little or no difference in efficacy or safety among the various 5-ASA formulations.

Similar pharmacokinetics of three dosing regimens comprising two oral delayed-release mesalamine formulations in healthy adult volunteers: Randomised, open-label, parallel-group study

Aims

Mesalamine is the first‐line therapy for treating mild‐to‐moderate ulcerative colitis. Multiple mesalamine formulations are available, with similar safety and efficacy profiles. Mesalamine is commonly administered as divided dosing, although once‐daily dosing may provide benefits for patients. We evaluated the pharmacokinetics of three dosing regimens of two oral delayed‐release mesalamine formulations in healthy adult volunteers.

Methods

A randomised, open‐label, parallel‐group study of mesalamine pharmacokinetics following Lialda 2 × 1.2 g once daily (QD) (dose A), Asacol 6 × 400 mg QD (dose B), or Asacol 2 × 400 mg three times daily (TID) (dose C) over 7 days. Assessments included 5‐aminosalicylic acid (5‐ASA) and N‐acetyl 5‐aminosalicylic acid (N‐Ac‐5‐ASA, primary metabolite) pharmacokinetics (A_e(%), AUC_0‐24 and C_max), safety and tolerability.

Results

All enrolled volunteers (n = 37) completed the study. Steady state was achieved for all treatments by day 4. Ratios (95% CI) of means for steady‐state AUC_0‐24 (dose A vs B 90.3% [39.8, 204.8], dose A vs C 123.5% [55.3, 275.7], dose B vs C 136.8% [61.3, 305.5]) and C_max (dose A vs B 106.0% [46.4, 242.2], dose A vs C 133.0% [59.1, 299.0], dose B vs C 125.5% [55.8, 282.1]) were similar for all 5‐ASA treatments. Mean urinary excretion of 5‐ASA plus N‐Ac‐5‐ASA was comparable between treatments (dose A 21.3%, dose B 20.2%, dose C 17.9%). All treatment regimens were well tolerated; no safety issues were observed.

Conclusions

Plasma and urine pharmacokinetics for Asacol TID, Asacol QD, and Lialda QD are similar, suggesting similar daily systemic exposures can be obtained with either TID or QD dosing. NCT00751699.

Colitis and Crohn's Foundation (India) consensus statements on use of 5-aminosalicylic acid in inflammatory bowel disease

Despite several recent advances in therapy in inflammatory bowel disease (IBD), 5-aminosalicylic acid (5-ASA) therapy has retained its place especially in ulcerative colitis. This consensus on 5-ASA is obtained through a modified Delphi process, and includes guiding statements and recommendations based on literature evidence (randomized trials, and observational studies), clinical practice, and expert opinion on use of 5-ASA in IBD by Indian gastroenterologists. The aim is to aid practitioners in selecting appropriate treatment strategies and facilitate optimal use of 5-ASA in patients with IBD.

Gut microbiota-driven drug metabolism in inflammatory bowel disease

BACKGROUND AND AIMS

The gut microbiota plays an important role in the metabolization and modulation of several types of drugs. With this study we aimed to review the literature about microbial drug metabolism of medication prescribed in inflammatory bowel disease practice.

METHODS

A systematic literature search was performed in Embase and PubMed from inception to October 2019. The search was conducted with predefined MeSH/Emtree and text terms. All studies about drug metabolism by microbiota of medication prescribed in inflammatory bowel disease practice were eligible. A total of 1018 records were encountered and 89 articles were selected for full text reading.

RESULTS

Intestinal bacterial metabolism or modulation is of influence in four specific drugs used in inflammatory bowel disease (mesalazines, methotrexate, glucocorticoids and thioguanine). The gut microbiota cleaves the azo-bond of sulfasalazine, balsalazide and olsalazine and releases the active moiety 5-aminosalicylic acid. It has an impact on the metabolization and potentially on the response of methotrexate therapy. Especially thioguanine can be converted by intestinal bacteria into the pharmacological active 6-thioguanine nucleotides without the requirement of host metabolism. Glucocorticoid compounds can be prone to bacterial degradation.

CONCLUSION

The human intestinal microbiota can have a major impact on drug metabolism and efficacy of medication prescribed in inflammatory bowel disease practice. A better understanding of these interactions between microbiota and drugs is needed and should be an integral part of the drug development pathway of new inflammatory bowel disease medication.

Rapid Review: Nonsteroidal Anti-inflammatory Agents and Aminosalicylates in COVID-19 Infections

In the current COVID-19 pandemic, there has been concern regarding the use of ibuprofen and other nonsteroidal anti-inflammatory agents by COVID-19 infected patients. Aminosalicylates (5-ASAs) are structurally similar and have anti-inflammatory functions that resemble those of nonsteroidal anti-inflammatory agents. Since 5-ASAs are a mainstay treatment for inflammatory bowel disease, the authors review the pharmacology of both classes of drugs and discuss the potential relevance of 5-ASAs in the ongoing discussion of medication use in patients infected with COVID-19.

Desirability Based Optimization of New Mesalazine Modified Release Formulations: Compression Coated Tablets and Mini Tablets in Capsules

Background:

Mesalazine (5-aminosalicylic acid, 5-ASA) is a drug substance with an antiinflammatory activity, which is mainly used in the symptomatic treatment of diseases, such as Ulcerative Colitis, the Crohn's disease and the idiopathic inflammatory bowel disease. Mesalazine exerts its effect locally in the inflamed area of the intestine and not through systematic absorption, therefore the investigation of its release characteristics from solid pharmaceutical formulations is of great importance.

Objective:

The development of novel mesalazine modified release formulations with improved properties, regarding drug release in the gastrointestinal tract, by utilisation of the Design of Experiments (DoE) approach.

Methods:

D-optimal experimental design was applied. A Simplex Lattice mixture design was used for the development of suitable capsules containing 4 mini tablets and a D-optimal mixture design was used for compression-coated tablets, with the following characteristics: ≤10% release in 2 h, to minimize its degradation in the upper gastrointestinal tract, 20-40% release in 5 h for mesalazine administration in the small intestine, and quantitative release in 12 h for colonic delivery. The dissolution experiments were conducted in gastrointestinal-like fluids and pectinases to simulate the pectinolytic enzymes present in the colon.

Results:

The optimal compositions were reached via the desirability function, as a compromise to the different responses. The optimal solutions for both formulations led to colon-specific delivery of the active substance with minimal 5-ASA release in the upper gastrointestinal tract and appeared to conform with the pre-determined characteristics. Hard gelatin capsules, when filled with mini-tablets led to the aimed modified release profile, having sigmoidal characteristics and compression coated tablets led to colonic delivery.

Conclusion:

Two novel mesalazine formulations were developed with the desirable colonic release, by conducting a minimal number of experiments, as suggested by DoE experimental design.

Real-World Data on Topical Therapies and Annual Health Resource Utilization in Hospitalized Swiss Patients with Ulcerative Colitis

Objectives

Topical treatment with aminosalicylates and/or budesonide was shown to be highly effective in patients with ulcerative colitis (UC), while reducing the likelihood of systemic adverse effects. However, previous research has shown that topical treatment is clearly underused. We aimed to evaluate the use of topical therapy in the real-world setting.

Methods

This is an observational study based on claims data of 201 Swiss adult patients who were hospitalized for UC between 2012 and 2014 and who were then followed for 1 year. A variety of factors presumably associated with topical treatment were examined. Annual health care utilization (UC-related medications, diagnostic procedures, consultations, and rehospitalizations) of patients with versus without topical therapy was compared.

Results

Of the 201 hospitalized UC patients, 82 (40.8%) were treated with topical 5-acetylsalicylic acid (ASA) and/or topical rectal steroids. The main factors significantly and positively associated with receiving topical treatment were the use of topical treatment in the year prior to the hospitalization, receiving oral 5-ASA, and living in an urban area. The mode of administration was further related to the language area. Patients with topical therapy significantly more often received other UC-related medications, such as combinations with systemic steroids. They significantly more often underwent colonoscopies and calprotectin measurements, and more often consulted a gastroenterologist in the follow-up, while there was no significant difference regarding rehospitalizations.

Conclusions

Topical treatment is underused in patients with UC, which stands in contrast to the current European Crohn's and Colitis Organization guidelines. Patients' preferences and considerations need to be taken into account when prescribing medical therapy.

Remission induction, maintenance, and endoscopic outcome with oral 5-aminosalicylic acid in intestinal Behçet's disease

BACKGROUND AND AIM

Oral 5-aminosalicylic acid (5-ASA) is recommended for the therapy of mild to moderate intestinal Behçet's disease (BD). However, the induction remission efficacy and endoscopic outcomes of 5-ASA are unknown. We investigated remission induction at 8 weeks, endoscopic outcomes until 52 weeks, and event-free survival at 52 weeks in patients with intestinal BD treated with 5-ASA.

METHODS

Forty-one patients with intestinal BD were treated with oral 5-ASA. Clinical remission was evaluated with the Crohn's disease activity index (CDAI). The endoscopic response was evaluated using the modified global gastrointestinal endoscopic assessment scores. Rescue therapy-free survival and surgery-free survival at 52 weeks were estimated, and predictive factors for a clinical response at weeks 8 and 52 were identified.

RESULTS

Seven patients (17%) withdrew 5-ASA early (≤ 8 weeks) because of adverse events. At week 8, clinical efficacy could be accurately evaluated in 28 patients, and the response and remission rates were 61% and 57%, respectively, using the CDAI. Endoscopic evaluation was achieved in 17 patients up to 52 weeks, and the endoscopic response and remission rates were 71% and 35%, respectively. The probabilities of rescue therapy-free survival and surgery-free survival were 73% and 100%, respectively, at 52 weeks in all 41 patients. The predictive factors for therapeutic effectiveness at week 8 were a higher baseline C-reactive protein level and CDAI, but they were negative predictive factors for a 52-week response.

CONCLUSIONS

5-ASA is effective for clinical and endoscopic induction and maintaining a response in patients with mild to moderate intestinal BD.

Bioavailability and swallowability of an age-appropriate, delayed-release mesalamine formulation in healthy volunteers

Objective: Delayed-release mesalamine 400 mg capsules containing four 100 mg tablets have been developed for children with ulcerative colitis who have difficulty swallowing. Bioavailability of the mesalamine capsules was compared with existing mesalamine tablets in healthy adults, and the effect of food on bioavailability from mesalamine capsules was determined. Tablet swallowability in healthy children was evaluated.

Methods: In the open-label, replicate-treatment, single-dose, crossover, comparative bioavailability study, healthy adult volunteers were randomized to one of four treatment sequences to receive mesalamine 400 mg tablets (fasted) twice, mesalamine 400 mg capsules (fasted) twice, and a mesalamine 400 mg capsule (with food) once, with ≥7 days between treatments. Pharmacokinetic (PK) parameters were calculated and analyzed using the reference-scaled average bioequivalence procedure. In the open-label, single-dose swallowability study, healthy children aged 5–11 years were asked to swallow eight placebo tablets identical to those contained in two mesalamine capsules.

Results: In the bioavailability study (n=160), mesalamine capsules and tablets in fasted volunteers exhibited similarly delayed absorption and were shown to be bioequivalent; statistical parameters calculated from PK values met the criteria for bioequivalence. A slight increase in mesalamine bioavailability was observed with food administration, but the delayed-release performance of the capsules was not affected. Overall safety profiles between capsules and tablets were similar. In the swallowability study (n=60), the majority of children swallowed eight placebo tablets, with slight variability between age groups.

Conclusion: Evaluation of PK parameters confirmed mesalamine capsules are bioequivalent to mesalamine tablets. Mesalamine capsules were well tolerated, can be administered with or without food, and are an age-appropriate product for children.

Mucosal 5-aminosalicylic acid concentration, drug formulation and mucosal microbiome in patients with quiescent ulcerative colitis

BACKGROUND

5-aminosalicylic acid (5-ASA) is the first-line therapy for ulcerative colitis (UC). 5-ASA acts locally in the colonic mucosa by numerous proposed mechanisms, and is metabolised by N-acetyltransferase (NAT). Large variations in mucosal 5-ASA concentrations have been reported, but the underlying mechanisms are not understood.

AIM

To study the relationship between 5-ASA concentration, 5-ASA formulation, NAT genotype and bacterial microbiome in patients with UC.

METHODS

Patients with quiescent UC, using monotherapy of Mezavant (n = 18), Asacol (n = 14) or Pentasa (n = 10), 4.0-4.8 g/day were included. 5-ASA was measured in colonic mucosal biopsies and serum by ultra-high performance liquid chromatography. NAT genotypes were determined by Sanger sequencing. Bacterial microbiome was sequenced from faeces and mucosa by 16S rRNA sequencing using Illumina Miseq.

RESULTS

Mezavant provided the highest mucosal 5-ASA levels (geometric mean 2.39 ng/mg), followed by Asacol (1.60 ng/mg, 33% lower, P = 0.50) and Pentasa (0.57 ng/mg, 76% lower, P = 0.033). Mucosal 5-ASA concentration was not associated with NAT genotype, but serum 5-ASA concentration and NAT1 genotype was associated (P = 0.044). Mucosal 5-ASA concentration was positively associated with mucosal bacterial diversity (P = 0.0005) and bacterial composition. High mucosal 5-ASA concentration was related to reduced abundance of pathogenic bacteria such as Proteobacteria, and increased abundance of several favourable bacteria such as Faecalibacterium.

CONCLUSIONS

Mucosal 5-ASA concentration is positively associated with bacterial diversity and a mucosal bacterial composition that are perceived favourable in UC. Mezavant yielded higher mucosal 5-ASA concentrations than Pentasa. 5-ASA may have beneficial effects on the mucosal microbiome, and high concentrations possibly amend dysbiosis in UC.

A Schiff-Base Modified Pt Nano-Catalyst for Highly Efficient Synthesis of Aromatic Azo Compounds

A Schiff-base modified Pt nano-catalyst was prepared via one-pot aldimine condensation and then impregnation-reduction of a platinum precursor, in which the Pt nanoparticles (NPs) with an average size of 2.3 nm were highly dispersed on the support. The as-prepared catalyst exhibited excellent activity and selectivity in the hydrogenation coupling synthesis of aromatic azo compounds from nitroaromatic under mild conditions. The strong metal–support interaction derived from the coordination of nitrogen sites on Schiff-base to Pt NPs enables stabilizing the Pt NPs and achieving the catalytic recyclability. The scheme can also tolerate various functional groups and offer an efficient method for the green synthesis of aromatic azo compounds.

Determination of Mesalamine levels in Human Milk as a Function of Dose

BACKGROUND

Oral mesalamine (5-amino salicylic acid [5-ASA]) is an anti-inflammatory agent commonly used to treat inflammatory bowel disease such as ulcerative colitis and Crohn's disease. The transfer of mesalamine into human milk has to date been poorly described at the current dosages and newer formulations. This study was designed to determine transfer of mesalamine into human milk as a function of maternal dose and time, and dosage form.

STUDY DESIGN

Ten breastfeeding mothers (age 28-41 years) suffering from inflammatory bowel disease were recruited who provided milk samples at 0, 1, 2, 4, 8, 12, and 24 hours after a single daily dose of oral mesalamine in pH-dependent gastroresistant coated tablets (1.2, 2.4, 3.6, and 4.8 g). Milk samples were analyzed using liquid chromatography/tandem mass spectrometry.

RESULTS

A total of 10 women were enrolled for the study. The calibration curve for mesalamine was linear over a concentration range of 0.32-200 ng/mL. Irrespective of maternal dose, mesalamine levels in milk were exceedingly low. However, a wide range of mesalamine levels were observed among all the participants. The relative infant doses were all lower than 0.1% (range 0.003-0.085%).

CONCLUSION

Regardless of dose and high variability, mesalamine levels in human milk were present in exceedingly low levels. The mothers in this study reported no side effects with their infants. These results suggest that the transfer of mesalamine into milk is very low and poses minimal risks to the breastfed infant.

AGA Technical Review on the Management of Mild-to-Moderate Ulcerative Colitis

Most patients with ulcerative colitis (UC) have mild-to-moderate disease activity, with low risk of colectomy, and are managed by primary care physicians or gastroenterologists. Optimal management of these patients decreases the risk of relapse and proximal disease extension, and may prevent disease progression, complications, and need for immunosuppressive therapy. With several medications (eg, sulfasalazine, diazo-bonded 5-aminosalicylates [ASA], mesalamines, and corticosteroids, including budesonide) and complex dosing formulations, regimens, and routes, to treat a disease with variable anatomic extent, there is considerable practice variability in the management of patients with mild-moderate UC. Hence, the American Gastroenterological Association prioritized clinical guidelines on this topic. To inform clinical guidelines, this technical review was developed in accordance with the Grading of Recommendations Assessment, Development and Evaluation framework for interventional studies. Focused questions included the following: (1) comparative effectiveness and tolerability of different oral 5-ASA therapies (sulfalsalazine vs diazo-bonded 5-ASAs vs mesalamine; low- (<2 g) vs standard (2-3 g/d) vs high-dose (>3 g/d) mesalamine); (2) comparison of different dosing regimens (once-daily vs multiple times per day dosing) and routes (oral vs rectal vs both oral and rectal); (3) role of oral budesonide in patients mild-moderate UC; (4) comparative effectiveness and tolerability of rectal 5-ASA and corticosteroid formulations in patients with distal colitis; and (5) role of alternative therapies like probiotics, curcumin, and fecal microbiota transplantation in the management of mild-moderate UC.

Designing novel perovskite-type strontium stannate (SrSnO3) and its potential as an electrode material for the enhanced sensing of anti-inflammatory drug mesalamine in biological samples

The enhanced electrocatalytic activity of an electrode developed with a perovskite-type inorganic material is witnessed very often because of its unique properties.

Smart gated magnetic silica mesoporous particles for targeted colon drug delivery: New approaches for inflammatory bowel diseases treatment

Magnetic mesoporous silica microparticles were loaded with safranin O (S1) and with hydrocortisone (S2) and the outer surface functionalized with a bulky azo derivative bearing urea moieties. Aqueous suspensions of both solids at pH 7.4 showed negligible payload release whereas a marked delivery was observed in the presence of sodium dithionite due to the rupture of the azo bonds. Besides, a moderate cargo release was observed at acidic pH due to the hydrolysis of the urea bonds that linked the azo derivative onto the external surface of the inorganic scaffolds. In vitro digestion models showed that S1 and S2 microparticles could be used for the controlled release of payload in the reducing colon environment (in which azoreductase enzymes are present). On the other hand, in vivo pharmacokinetic studies in rats showed that safranine O release from S1 microparticles was concentrated in colon. The performance of S2 microparticles for the treatment of colitis in rats (induced by oral administration of a 2,4,6-trinitrobenzenesulfonic acid solution) was tested. The controlled release of hydrocortisone from S2 in the colon of injured rats induced marked reduction in colon/body weight ratio and in clinical activity score. Also, histological studies showed a marked decrease in inflammation followed by intensive regeneration and almost normal mucosal structure of the individuals treated with S2. Besides, the use of a magnetic belt increased the therapeutic performances of S2 due to an enhanced retention time of the particles in the colon.

Synthesis and Characterisation of New Sulfonamide Chalcones Containing an azo Group

The synthesis and characterisation of a new type of chalcone bearing a –N=N– bond is reported using an environmentally benign approach. The synthesis consists of two steps. ( E)-4-((5-acetyl-2-hydroxyphenyl)diazenyl)benzenesulfonamide was synthesised by an easy structural modification of sulfanilamide. The key step then involved the solvent-free Claisen–Schmidt condensation of benzaldehydes to form the chalcones. The structures of all compounds were confirmed by FTIR, NMR and MS spectroscopy.

Urinalysis of MMX-mesalazine as a tool to monitor 5-ASA adherence in daily IBD practice

Adherence is pivotal but challenging in ulcerative colitis (UC) treatment. Many methods to assess adherence are subjective or have limitations. (Nac-)5-aminosalicylic acid (5-ASA) urinalysis by high-performance liquid chromatography (HPLC) seems feasible and reproducible in healthy volunteers. We performed a prospective study in adult quiescent UC patients to evaluate the feasibility of spot (Nac-)5-ASA urinalysis by HPLC to assess adherence in daily inflammatory bowel disease (IBD) care. Twenty-nine patients (51.7% male, mean age 52 ± 11 years) were included (median FU 9 months) and weekly spot urine samples were collected. We found large variation in spot (Nac-)5-ASA urinary excretion that was unrelated to brand, dosing schedule or dosage of 5-ASA. In conclusion, spot (Nac-)5-ASA urinalysis is not applicable to assess 5-ASA adherence in daily IBD care.

Regulatory framework on bioequivalence criteria for locally acting gastrointestinal drugs: the case for oral modified release mesalamine formulations

INTRODUCTION

Bioequivalence testing for locally acting gastrointestinal drugs is a challenging issue for both regulatory authorities and pharmaceutical industries. The international regulatory framework has been characterized by the lack of specific bioequivalence tests that has generated a negative impact on the market competition and drug use in clinical practice. Areas covered: This review article provides an overview of the European Union and United States regulatory frameworks on bioequivalence criteria for locally acting gastrointestinal drugs, also discussing the most prominent scientific issues and advances that has been made in this field. A focus on oral modified release mesalamine formulations will be also provided, with practical examples of the regulatory pathways followed by pharmaceutical companies to determine bioequivalence. Expert commentary: The development of a scientific rationale to demonstrate bioequivalence in this field has been complex and often associated with uncertainties related to scientific and regulatory aspects. Only in recent years, thanks to advanced knowledge in this field, the criteria for bioequivalence assessment are undergoing substantial changes. This new scenario will likely result in a significant impact on pharmaceutical companies, promoting more competition through a clearer regulatory approach, conceived for streamlining the demonstration of therapeutic equivalence for locally acting gastrointestinal drugs.

The safety of non-biological treatments in Ulcerative Colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory bowel disease with a relapsing-remitting course that determines significant morbidity and can associate with local complications and/or extra-intestinal manifestations. Pharmacological therapies are often required for a lifetime with possible risks of toxicity and side effects. Areas covered: Non-biological therapies (i.e. aminosalicylates, corticosteroids and immunosuppressive drugs) are widely used in UC patients for controlling the active phases of the disease and maintaining remission. Expert Opinion: Aminosalycilates have a good safety profile with a low risk of idiosyncrasic reactions. In contrast, the use of corticosteroids and immunosuppressive drugs can associate with unacceptable side effects, some of which are potentially life threatening. Mechanisms underlying the development of these side effects are not fully understood and strategies aimed to prevent them have not yet been standardized. However, clinicians should monitor the patients during therapy to recognize the adverse events at an early stage of the occurrence. New drugs that selectively target molecules involved in the amplification of the ongoing mucosal inflammation are currently under investigation. Preliminary data indicate that such compounds have better overall safety and tolerability than corticosteroids and immunosuppressive drugs.

Measurement of in vivo Gastrointestinal Release and Dissolution of Three Locally Acting Mesalamine Formulations in Regions of the Human Gastrointestinal Tract

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.