Mesalazine. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in chronic inflammatory bowel disease

Structural and Functional Characterization of a Putative Type VI Secretion System Protein in Cronobacter sakazakii as a Potential Therapeutic Target: A Computational Study

Background

Cronobacter sakazakii, a foodborne pathogen with a fatality rate of 33%, is a rod-shaped, Gram-negative, non-spore-forming bacterium responsible for causing meningitis, bacteremia, and necrotizing enterocolitis. Despite many unknown functions of hypothetical proteins in bacterial genomes, bioinformatic techniques have successfully annotated their roles in various pathogens.

Objectives

The aim of this investigation is to identify and annotate the structural and functional properties of a hypothetical protein (HP) from Cronobacter sakazakii 7G strain (accession no. WP_004386962.1, 277 residues) using computational tools.

Methods

Multiple bioinformatic tools were used to identify the homologous protein and to construct and validate its 3D structure. A 3D model was generated using SWISS-MODEL and validated using tools, developing a reliable 3D structure. The STRING and CASTp servers provided information on protein-protein interactions and active sites, identifying functional partners.

Results

The putative protein was soluble, stable, and localized in the cytoplasmic membranes, indicating its biological activity. Functional annotation identified TagJ (HsiE1) within the protein, a member of the ImpE superfamily involved in the transport of toxins and a part of the bacterial type VI secretion system (T6SS). The 3-dimensional structure of this protein was validated through molecular docking involving 6 different compounds. Among these, ceforanide demonstrated the strongest binding scores, -7.5 kcal/mol for the hypothetical protein and -7.2 kcal/mol for its main template protein (PDB ID: 4UQX.1).

Conclusion

Comparative genomics study suggests that the protein found in C. sakazakii may be a viable therapeutic target because it seems distinctive and different from human proteins. The results of multiple sequence alignment (MSA) and molecular docking supported HP's potential involvement as a T6SS. These in silico results represent that the examined HP could be valuable for studying C. sakazakii infections and creating medicines to treat C. sakazakii-mediated disorders.

Optimization, cellular uptake, and in vivo evaluation of Eudragit S100-coated bile salt-containing liposomes for oral colonic delivery of 5-aminosalicylic acid

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 Cmax 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.

Solubility of mesalazine in pseudo-binary mixtures of choline chloride/ethylene glycol deep eutectic solvent and water at 293.15 K to 313.15 K

Mesalazine (5-ASA) is a medication utilized to treat inflammatory bowel diseases involving ulcerative colitis and Crohn's disease. Mesalazine has fewer side effects but the low solubility and bioavailability of it is responsible for its delayed onset of action. Hence, the goal of this study is to determine the molar solubility of 5-ASA in aqueous pseudo-binary mixtures containing low toxic biocompatible choline chloride/ethylene glycol deep eutectic solvent (ChCl/EG DES) with DES mass fraction of 0.0-1.0 using a shake-flask technique at 293.2-313.2 K and approximately 85 kPa. The experimental results indicated that the solubility of 5-ASA enhanced by addition of DES mass fraction and also increasing temperature. The molarity values of 5-ASA were then modelled by some traditional cosolvency models, and regressed each model parameters. The back-computed molarity of 5-ASA using the selected cosolvency models presented a good consistency with the experimental data (lower mean percentage deviation than 5.14%). Moreover, the Gibbs and van't Hoff equations were employed to compute the thermodynamic functions of 5-ASA dissolution process in ChCl/EG DES + water from the temperature dependency of solubility data. This analysis presented an endothermic and entropy-driven process of 5-ASA dissolution in ChCl/EG DES + water. Furthermore, enthalpy-entropy compensation analysis represented non-linear enthalpy dissolution vs. Gibbs free energy compensation plots with positive and negative slopes for 5-ASA whereas the positive and negative slopes were probably due to the enhance in solvation of 5-ASA by ChCl/EG DES molecules and the solvent-structure loosing, respectively.

Investigation of mesalazine as an antifibrotic drug following myocardial infarction in male mice

OBJECTIVES

Myocardial infarction (MI) initiates a complex reparative response during which damaged cardiac muscle is replaced by connective tissue. While the initial repair is essential for survival, excessive fibrosis post-MI is a primary contributor to progressive cardiac dysfunction, and ultimately heart failure. Currently, there are no approved drugs for the prevention or the reversal of cardiac fibrosis. Therefore, we tested the therapeutic potential of repurposed mesalazine as a post-MI therapy, as distinct antifibrotic effects have recently been demonstrated.

METHODS

At 8 weeks of age, MI was induced in male C57BL/6J mice by LAD ligation. Mesalazine was administered orally at a dose of 100 μg/g body weight in drinking water. Fluid intake, weight development, and cardiac function were monitored for 28 days post intervention. Fibrosis parameters were assessed histologically and via qPCR.

RESULTS

Compared to controls, mesalazine treatment offered no survival benefit. However, no adverse effects on heart and kidney function and weight development were observed, either. While total cardiac fibrosis remained largely unaffected by mesalazine treatment, we found a distinct reduction of perivascular fibrosis alongside reduced cardiac collagen expression.

CONCLUSIONS

Our findings warrant further studies on mesalazine as a potential add-on therapy post-MI, as perivascular fibrosis development was successfully prevented.

Retrospective investigation of mesalamine intolerance in patients with ulcerative colitis

Mesalamine is a key drug in the treatment of ulcerative colitis (UC) for both induction and maintenance therapy. On the other hand, it is known that there are some cases of mesalamine intolerance that are difficult to distinguish from symptoms due to aggravation of UC. The aim of this study is to investigate the clinical characteristic of mesalamine intolerance in UC. A retrospective, observational study was conducted. We enrolled 31 patients who were diagnosed as mesalamine intolerance between April 2015 to March 2020. We examined clinical features, time to onset, drug types of mesalamine, DLST positive rate, colonoscopy findings, disease activity, and clinical course after diagnosis. The average dose of mesalamine was 3.69 g and DLST-positive was 57.1%. Within the first 2 weeks from the start of mesalamine, 51.6% showed symptoms of intolerance. The serum CRP level was relatively high at ≥10.0 mg/dl in 53.6% of the cases. There was no difference in clinical background, symptoms, or laboratory findings between patients with DLST-positive and negative. In this study, we clarified the clinical characteristics of mesalamine intolerant patients, and found no difference in the clinical background or success rate of desensitization therapy between positive and negative DLST cases.

Population pharmacokinetics and IVIVC for mesalazine enteric-coated tablets

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.

5-Aminosalicylic Acid Ameliorates Colitis and Checks Dysbiotic Escherichia coli Expansion by Activating PPAR-γ Signaling in the Intestinal Epithelium

An expansion of Enterobacterales in the fecal microbiota is a microbial signature of dysbiosis that is linked to many noncommunicable diseases, including ulcerative colitis. Here, we used Escherichia coli, a representative of the Enterobacterales, to show that its dysbiotic expansion during colitis can be remediated by modulating host epithelial metabolism.

5-Aminosalicylic acid (5-ASA), a peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, is a widely used first-line medication for the treatment of ulcerative colitis, but its anti-inflammatory mechanism is not fully resolved. Here, we show that 5-ASA ameliorates colitis in dextran sulfate sodium (DSS)-treated mice by activating PPAR-γ signaling in the intestinal epithelium. DSS-induced colitis was associated with a loss of epithelial hypoxia and a respiration-dependent luminal expansion of Escherichia coli, which could be ameliorated by treatment with 5-ASA. However, 5-ASA was no longer able to reduce inflammation, restore epithelial hypoxia, or blunt an expansion of E. coli in DSS-treated mice that lacked Pparg expression specifically in the intestinal epithelium. These data suggest that the anti-inflammatory activity of 5-ASA requires activation of epithelial PPAR-γ signaling, thus pointing to the intestinal epithelium as a potential target for therapeutic intervention in ulcerative colitis.

Inhibition of 3D colon cancer stem cell spheroids by cytotoxic RuII-p-cymene complexes of mesalazine derivatives

The Ru(ii) complex of an imidazole-mesalazine Schiff base is a unique example showing growth inhibition of 3D-colon cancer stem cell spheroids and bulk colon cancer cells at lower dosage than salinomycin or oxaliplatin. Unlike oxaliplatin which increases the expression of stemness genes (SOX2, KLF4, HES1 and Oct4), these complexes maintain a tight regulation.

The culprit of mesalamine intolerance: case series and literature review

Background

Mesalamine is a first-line drug in the treatment of inflammatory bowel diseases, while its intolerance occasionally occurs in clinical practice. Most of adverse reactions are due to the active components, which may lead to step-up treatment, but excipients are sometimes regarded as the chief culprit and can be resolved by transferring to other preparations. Thus, distinguishing different kinds of intolerance is extremely important for clinical decision.

Case presentation

Here we reported two cases with mesalamine intolerance. One patient with 5-aminosalicylic acid intolerance had similar adverse reactions to the treatment of different preparations, while another patient with excipients intolerance failed to tolerate Salofalk but could take Pentasa with no symptoms. Meanwhile, clinical manifestations were analysed and the previous reports referring to excipients intolerance were summarized. It is interesting to found that the patients with excipients intolerance mainly presented with acute skin symptoms, such as skin rash, urticaria and angioedema. But the adverse effects of 5-ASA in previous reports include fever, headache, rash, nausea, vomiting, dyspepsia, hepatotoxicity, pancreatitis, interstitial nephritis, pneumonitis, pericarditis and so on.

Conclusions

5-aminosalicylic acid and excipients should be taken into consideration together when mesalamine-related adverse events occur. Of note, a diagnosis of excipient intolerance should be paid more attention in the patients with the presentation of acute skin symptoms.

Microbiota-nourishing Immunity and Its Relevance for Ulcerative Colitis

An imbalance in our microbiota may contribute to many human diseases, but the mechanistic underpinnings of dysbiosis remain poorly understood. We argue that dysbiosis is secondary to a defect in microbiota-nourishing immunity, a part of our immune system that balances the microbiota to attain colonization resistance against environmental exposure to microorganisms. We discuss this new hypothesis and its implications for ulcerative colitis, an inflammatory bowel disease of the large intestine.

Synthesis ofmeta-substituted anilinesviaa three-component reaction of acetone, amines, and 1,3-diketones

A facilede novosynthesis ofmeta-substituted arylamines based on three-component cyclo-condensation/aromatization ofin situgenerated imines with 1,3-diketones is described.

Colonocyte metabolism shapes the gut microbiota

An imbalance in the colonic microbiota might underlie many human diseases, but the mechanisms that maintain homeostasis remain elusive. Recent insights suggest that colonocyte metabolism functions as a control switch, mediating a shift between homeostatic and dysbiotic communities. During homeostasis, colonocyte metabolism is directed toward oxidative phosphorylation, resulting in high epithelial oxygen consumption. The consequent epithelial hypoxia helps to maintain a microbial community dominated by obligate anaerobic bacteria, which provide benefit by converting fiber into fermentation products absorbed by the host. Conditions that alter the metabolism of the colonic epithelium increase epithelial oxygenation, thereby driving an expansion of facultative anaerobic bacteria, a hallmark of dysbiosis in the colon. Enteric pathogens subvert colonocyte metabolism to escape niche protection conferred by the gut microbiota. The reverse strategy, a metabolic reprogramming to restore colonocyte hypoxia, represents a promising new therapeutic approach for rebalancing the colonic microbiota in a broad spectrum of human diseases.

Healthy hosts rule within: ecological forces shaping the gut microbiota

A balanced gut microbiota is important for human health, but the mechanisms that maintain homeostasis are incompletely understood. Recent insights suggest the host plays a key role in shaping its gut microbiota to be beneficial. While host control in the small intestine curbs bacterial numbers to avoid competition for simple sugars and amino acids, the host limits oxygen availability in the large intestine to obtain microbial fermentation products from fiber. Epithelial cells are major players in imposing ecological control mechanisms, which involves the release of antimicrobial peptides by small-intestinal Paneth cells and maintenance of luminal anaerobiosis by epithelial hypoxia in the colon. Harnessing these epithelial control mechanisms for therapeutic means could provide a novel lynchpin for strategies to remediate dysbiosis.

5-aminosalicylic acid improves lipid profile in mice fed a high-fat cholesterol diet through its dual effects on intestinal PPARγ and PPARα

Obesity is associated with a series of metabolic complications, including dyslipidemia and insulin resistance (IR) that lack effective therapies. In recent years, intestinal inflammation has been suggested to contribute to obesity related metabolic syndrome and targeting gut inflammation with 5-ASA improves diet induced IR, however, its role in dyslipidemia is unknown and has never been explored. In the present study, we reported for the first time that administration of 5-ASA for 12 weeks significantly improved lipid profile by repressing plasma triglycerides and free cholesterol levels in mice fed high-fat cholesterol diet (HFC). In addition, liver lipids were significantly reduced by 5-ASA treatment in HFC-fed mice. Mechanistically, anti-inflammatory genes peroxisome proliferator-activated receptor-γ (Pparγ) and M2 marker, such as Mrc1 and Ym1, were remarkably upregulated, while pro-inflammation gene monocyte chemoattractant protein-1 (Mcp-1) were downregulated in small intestine of mice treated by 5-ASA. Further, 5-ASA improved gastrointestinal barrier by increasing the expression of the tight junction marker ZO-1. 5-ASA also enhanced cholesterol translocation by elevating genes expression of Npc1l1 and Abcg5/8. Moreover, mice fed HFC 5-ASA expressed increased Pparα in small intestinal and its target genes function in lipid oxidation and hydrolysis were remarkable elevated. Taken together, we reported a novel role of 5-ASA which may serve as a therapy target intestinal inflammation induced dyslipidemia.

Importance of the Evaluation of N-Acetyltransferase Enzyme Activity Prior to 5-Aminosalicylic Acid Medication for Ulcerative Colitis

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.

A novel pH-enzyme-dependent mesalamine colon-specific delivery system

The aim of the present study was to design a new pH–enzyme double-dependent mesalamine colon-specific delivery system. The drug release behaviors in vitro and pharmacokinetics and biodistribution in vivo were further evaluated. The mean particle diameters of mesalamine-coated microparticles were 312.2 µm. In vitro, a small amount of mesalamine was released in HCl at a pH of 1.2 and PBS medium at a pH of 7.4 for 5 hours, and 71% of the entrapped mesalamine was further released during the subsequent 20 hours of incubation. A greater area under the plasma concentration–time curve (AUC)_0–t was obtained for the coated microparticles (1.9-fold) compared to the suspensions group, which indicated that the encapsulated mesalamine had mostly been absorbed in rats over the period of 12 hours. The AUC_0–t of the coated microparticles in colon was 2.63-fold higher compared to the suspensions (P<0.05). Hence, mesalamine-coated microparticles are considered to maintain the drug concentration within target ranges for a long period of time.

Mesalazine Modified-Release Tablet in the Treatment of Ulcerative Colitis in the Remission Phase: A Chinese, Multicenter, Single-Blind, Randomized Controlled Study

INTRODUCTION

This study aimed to compare the efficacy and safety of two mesalazine formulations in the treatment of Chinese patients with ulcerative colitis (UC) in the remission phase.

METHODS

In this multicenter, single-blind, randomized controlled study conducted from November 2010 to August 2012, 251 patients with UC from 18 hospitals were enrolled. The patients were randomized to treatment with mesalazine modified-release tablets (MR group, n = 126) or other enteric-coated tablets (EC group, n = 125), at 800 mg three-times daily for 48 weeks. The primary efficacy parameter was the rate of non-emergence of bloody stool. If the lower limit of the 95% confidence interval (CI) of the primary efficacy measure was over -10%, the modified-release tablets were considered non-inferior to the enteric-coated tablets. The secondary efficacy parameters included the period of non-emergence of bloody stool and the period of non-recurrence of UC. The incidences of adverse events and adverse drug reactions were compared between the two groups.

RESULTS

At 48 weeks of maintenance treatment, the rates of non-emergence of bloody stool were 82.99% (95% CI 73.53-92.45%) and 73.30% (95% CI 64.04-82.56%) in the MR and EC groups, respectively, and the difference between the two groups was 9.69% (95% CI -1.15-20.53%). There was no significant difference in the period of non-emergence of bloody stool and the period of non-recurrence of UC between the two groups (P > 0.05). The incidences of adverse events were 48.78% (60/123) and 48.00% (60/125) in the MR and EC groups, respectively (P = 0.902). The incidences of adverse drug reactions were 16.26% (20/123) and 13.60% (17/125) in the MR and EC groups, respectively (P = 0.556).

CONCLUSION

Mesalazine modified-release tablets were non-inferior to the enteric-coated tablets and may be considered an effective and safe treatment alternative for the maintenance of remission in Chinese patients with UC.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01257399.

FUNDING

Tillotts Pharma AG.

Mesalazine Modified-Release Tablet in the Treatment of Ulcerative Colitis in the Active Phase: A Chinese, Multicenter, Single-Blind, Randomized Controlled Study

INTRODUCTION

This study compared the efficacy and safety of two mesalazine formulations in the treatment of Chinese patients with mildly to moderately active ulcerative colitis (UC).

METHODS

In this multicenter, single-blind, randomized controlled study of 251 patients with active UC conducted from November 2010 to January 2012, subjects were randomized to treatment with mesalazine modified-release tablets (MR group, n = 123) or enteric-coated tablets (EC group, n = 128) at 800 mg three-times daily for 8 weeks. The primary efficacy measure was the decrease in UC Disease Activity Index (UCDAI) at final evaluation. If the 95% confidence interval (CI) lower limit of the difference of the decrease in UCDAI between groups was over -1.0, mesalazine modified-release tablets were considered non-inferior to mesalazine enteric-coated tablets. The change in UCDAI in patients with mild and moderate (UCDAI 3-5 and 6-8 at enrollment, respectively) UC was analyzed. Secondary efficacy measures were remission and efficacy rates. Incidences of adverse drug reactions (ADRs) were calculated.

RESULTS

The decreases in UCDAI at final evaluation were 2.84 and 2.56 in the MR and EC groups, respectively, with a difference of 0.27 between groups (95% CI -0.34, 0.88). The remission rates were 48.33% (58/120) and 55.65% (69/124), and the efficacy rates were 63.33% (76/120) and 66.94% (83/124) in the MR and EC groups, respectively (all P > 0.05). In patients with mild UC, the decreases in UCDAI were 2.16 and 2.05 in the MR and EC groups, respectively, while in patients with moderate UC they were 3.49 and 3.03, respectively (all P > 0.05). The incidences of ADRs in the MR and EC groups were 6.61% (8/121) and 10.24% (13/127), respectively (P > 0.05). No serious ADRs were reported during the study.

CONCLUSION

Mesalazine modified-release tablets are non-inferior to enteric-coated tablets and are an effective and safe treatment option in Chinese patients with mildly to moderately active UC.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT01257386.

FUNDING

Tillotts Pharma AG.

Therapeutic efficacy of pH-dependent release formulation of mesalazine on active ulcerative colitis resistant to time-dependent release formulation: analysis of fecal calprotectin concentration

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.

Focal enhanced gastritis and macrophage microaggregates in the gastric mucosa: potential role in the differential diagnosis between Crohn's disease and ulcerative colitis

CONTEXT AND OBJECTIVES

Focally enhanced gastritis and macrophage microaggregates are found in the upper gastrointestinal involvement of Crohn's disease, and may reflect an underlying defective innate immunity. These features, however, are also described in patients with Helicobacter pylori infection. The role of these gastric abnormalities in the diagnosis of Crohn's disease was assessed in a population with high prevalence of H. pylori infection.

METHODS

Thirty-seven Crohn's disease, 26 ulcerative colitis, and 30 control patients were included. The H. pylori status was evaluated by the rapid urease test and histology. The presence of focally enhanced gastritis and macrophage microaggregates was recorded.

RESULTS

Focally enhanced gastritis was present in 24% of Crohn's disease patients, 4% of ulcerative colitis patients and 11.5% of controls, presenting an overall sensitivity and specificity for Crohn's disease of 24% and 88%, respectively. Macrophage microaggregates were found in all groups, but were only detected in ulcerative colitis and controls in association with H. pylori infection, with an overall sensitivity and specificity for Crohn's disease of 61% and 69%, respectively. In the absence of H. pylori infection, focally enhanced gastritis and macrophage microaggregates were significantly associated with Crohn's disease (P<0.02 and P = 0.001 respectively).

CONCLUSIONS

Focally gastritis and macrophage microaggregates are suggestive of Crohn's disease only in H. pylori-negative specimens.

Effect of MMX® mesalamine coadministration on the pharmacokinetics of amoxicillin, ciprofloxacin XR, metronidazole, and sulfamethoxazole: results from four randomized clinical trials

Background

MMX^® mesalamine is a once daily oral 5-aminosalicylic acid formulation, effective in induction and maintenance of ulcerative colitis remission. Patients on long-term mesalamine maintenance may occasionally require concomitant antibiotic treatment for unrelated infections.

Aim

To evaluate the potential for pharmacokinetic interactions between MMX mesalamine and amoxicillin, ciprofloxacin extended release (XR), metronidazole, or sulfamethoxazole in four open-label, randomized, placebo-controlled, two-period crossover studies.

Methods

In all four studies, healthy adults received placebo once daily or MMX mesalamine 4.8 g once daily on days 1–4 in one of two treatment sequences. In studies 1 and 2, subjects also received a single dose of amoxicillin 500 mg (N=62) or ciprofloxacin XR 500 mg (N=30) on day 4. In studies 3 and 4, subjects received metronidazole 750 mg twice daily on days 1–3 and once on day 4 (N=30); or sulfamethoxazole 800 mg/trimethoprim 160 mg twice daily on days 1–3 and once on day 4 (N=44).

Results

MMX mesalamine had no significant effects on systemic exposure to amoxicillin, ciprofloxacin, or metronidazole; the 90% confidence intervals (CIs) around the geometric mean ratios (antibiotic + MMX mesalamine: antibiotic + placebo) for maximum plasma concentration (C_max) and area under the plasma concentration–time curve (AUC) fell within the predefined equivalence range (0.80–1.25). Sulfamethoxazole exposure increased by a statistically significant amount when coadministered with MMX mesalamine; however, increased exposure (by 12% in C_max at steady state; by 15% in AUC at steady state) was not considered clinically significant, as the 90% CIs for each point estimate fell entirely within the predefined equivalence range. Adverse events in all studies were generally mild.

Conclusion

MMX mesalamine may be coadministered with amoxicillin, ciprofloxacin, metronidazole, or sulfamethoxazole, without affecting pharmacokinetics or safety of these antibiotics.

ClinicalTrials.gov identifiers

NCT01442688, NCT01402947, NCT01418365, and NCT01469637.

5-ASA colonic mucosal concentrations resulting from different pharmaceutical formulations in ulcerative colitis

AIM: To compare the mucosal concentrations of 5-aminosalicylic acid (5-ASA) resulting from different pharmaceutical formulations and analyse the influence of inflammation on the mucosal concentrations.

METHODS: The study included 130 inflammatory bowel disease (IBD) patients receiving 5-ASA as pH-dependent-release formulations (73 patients), time-dependent-release formulations (11 patients), or pro-drugs (18 patients). In addition, 28 patients were receiving topical treatment (2-4 g/d) with pH-dependent-release formulations. Endoscopic biopsies were obtained from the sigmoid region during the colonoscopy. The 5-ASA concentrations (ng/mg) were measured in tissue homogenates using high-pressure liquid chromatography with electrochemical detection. The t test and Mann-Whitney test, when appropriate, were used for statistical analysis.

RESULTS: Patients receiving pH-dependent-release formulations showed significantly higher mucosal concentrations of 5-ASA (51.75 ± 5.72 ng/mg) compared with patients receiving pro-drugs (33.35 ± 5.78 ng/mg, P = 0.01) or time-dependent-release formulations (38.24 ± 5.53 ng/mg, P = 0.04). Patients with endoscopic remission had significantly higher mucosal concentrations of 5-ASA than patients with active disease (60.14 ± 7.95 ng/mg vs 35.66 ± 5.68 ng/mg, P = 0.02). Similar results were obtained when we compared patients with the histological appearance of remission and patients with active histological inflammation (67.53 ± 9.22 ng/mg vs 35.53 ± 5.63 ng/mg, P < 0.001). Significantly higher mucosal concentrations of 5-ASA were detected in patients treated with both oral and topical treatments in combination compared with patients who received oral treatment with pH-dependent-release formulations alone (72.33 ± 11.23 ng/mg vs 51.75 ± 5.72 ng/mg, P = 0.03).

CONCLUSION: IBD patients showed significant variability in mucosal 5-ASA concentrations depending on the type of formulation, and the highest mean concentration was achieved using pH-dependent-release formulations.

Current and emerging drugs for the treatment of inflammatory bowel disease

During the last decade a large number of biological agents against tumor necrosis factor-α (TNF-α), as well as many biochemical substances and molecules specifically for the medical treatment of patients with inflammatory bowel disease (IBD), have been developed. This enormous progress was a consequence of the significant advances in biotechnology along with the increased knowledge of the underlying pathophysiological mechanisms involved in the pathogenesis of IBD. However, conventional therapies remain the cornerstone of treatment for most patients. During recent years conventional and biologic IBD therapies have been optimized. Newer mesalazine formulations with a reduced pill size and only one dose per day demonstrate similar efficacy to older formulations. New corticosteroids retain the efficacy of older corticosteroids while exhibiting a higher safety profile. The role of antibiotics and probiotics has been further clarified. Significant progress in understanding thiopurine metabolism has improved the effective dose along with adjunctive therapies. Quite a large number of substances and therapies, including biologic agents other than TNF-α inhibitors, unfractionated or low-molecular-weight heparin, omega-3 polyunsaturated fatty acids, microbes and microbial products, leukocytapheresis, and other substances under investigation, could offer important benefits to our patients. In this paper we review the established and emerging therapeutic strategies in patients with Crohn's disease and ulcerative colitis.

Direct comparison of two different mesalamine formulations for the maintenance of remission in patients with ulcerative colitis: a double-blind, randomized study

BACKGROUND

Mesalamine has been used as the first-line medication for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two different mesalamine formulations in the maintenance of remission in patients with UC.

METHODS

In a multicenter, double-blind, randomized study, 131 patients with quiescent UC were assigned to two groups: 65 to receive a pH-dependent release formulation of mesalamine at 2.4 g/day (pH-2.4 g) and 66 to receive a time-dependent release formulation of mesalamine at 2.25 g/day (Time-2.25 g). Both formulations were administered three times daily for 48 weeks. The primary endpoint was the proportion of patients without bloody stools.

RESULTS

In the full analysis set (n = 130), the proportion of patients without bloody stools was 76.9% in the pH-2.4 g and 69.2% in the Time-2.25 g, demonstrating the noninferiority of pH-2.4 g to Time-2.25 g. No statistically significant difference in time to bloody stools was found between the two formulations (P = 0.27, log-rank test), but the time to bloody stools tended to be longer in pH-2.4 g compared to Time-2.25 g, and a similar trend was observed with regard to the time to relapse. No differences were observed between the safety profiles of the two formulations.

CONCLUSIONS

The pH- and time-dependent release of mesalamine formulations were similarly safe and effective. Interestingly, the remission phase tended to be longer in the group that received the pH-dependent formulation compared to the group that received the time-dependent formulation (UMIN Clinical Trials Registry, no. C000000289).

Direct comparison of two different mesalamine formulations for the induction of remission in patients with ulcerative colitis: a double-blind, randomized study

BACKGROUND

Mesalamine is the first-line drug for the treatment of ulcerative colitis (UC). We directly compared the efficacy and safety of two mesalamine formulations for the induction of remission in patients with UC.

METHODS

In a multicenter, double-blind, randomized study, 229 patients with mild-to-moderate active UC were assigned to 4 groups: 66 and 65 received a pH-dependent release formulation of 2.4 g/day (pH-2.4 g) or 3.6 g/day (pH-3.6 g), respectively; 65 received a time-dependent release formulation of 2.25 g/day (Time-2.25 g), and 33 received placebo (Placebo). The drugs were administered three times daily for eight weeks. The primary endpoint was a decrease in the UC disease activity index (UC-DAI).

RESULTS

In the full analysis set (n = 225) the decrease in UC-DAI in each group was 1.5 in pH-2.4 g, 2.9 in pH-3.6 g, 1.3 in Time-2.25 g and 0.3 in Placebo, respectively. These results demonstrate the superiority of pH-3.6 g over Time-2.25 g (P = 0.003) and the noninferiority of pH-2.4 g to Time-2.25 g. Among the patients with proctitis-type UC, a significant decrease in UC-DAI was observed in pH-2.4 g and pH-3.6 g as compared to Placebo, but not in Time-2.25 g. No differences were observed in the safety profiles.

CONCLUSIONS

Higher dose of the pH-dependent release formulation was more effective for induction of remission in patients with mild-to-moderate active UC. Additionally, the pH-dependent release formulation was preferable to the time-dependent release formulation for patients with proctitis-type UC (UMIN Clinical Trials Registry, no. C000000288).

An unusual case of mesalazine intoxication: Oral and rectal overloading of the rectal suppository form

Drugs containing 5-acetylsalicylic acid (5-ASA) have been commonly used for inflammatory bowel diseases for more than half a century, but no case about overdose of suppository form of mesalazine which was taken both orally and rectally has been reported in the related literature up to now. In the present case, a 20-year-old male patient who took 14.5 g of mesalazine rectally and orally for suicide purpose is discussed. He was an ulcerative colitis patient and depressed about his illness and routine life traffic. Although it was hard for him to take the suppository form orally because of its bad taste and structure, he took it with the help of water. In the patient’s colonoscopy, diffuse hyperemia and edema extending from the anal channel to the proximal rectal mucosa and a 1.5 cm diameter ulcer expanding from anal channel through the rectum were identified. No pathology was found in the upper gastrointestinal endoscopy. Routine laboratory examination was performed and no abnormality was identified in the patient’s total blood account, biochemical parameters and full-urine examination. In the control rectoscopy applied to the patient 15 days later, recovery of the ulcer was observed and he was discharged to be followed in the psychiatry clinic.

In-vitroandIn-vivoEvaluation of Mesalazine–Guar Gum Matrix Tablets for Colonic Drug Delivery

The aim of this study was to develop colon-specific delivery systems for mesalazine (5-ASA) using guar gum as a carrier. A colon specific matrix tablet of mesalazine with guar gum was evaluated by in vitro and in vivo X-ray studies in humans. Two different types of guar gum were used in the experiments. Tablets were prepared by the slugging method. The physical properties of tablets were tested and in vitro release studies were performed by a flow-through cell apparatus with and without galactomannanase enzyme. The type and the amount of guar gum affected the in vitro release of drug from the matrix tablets. High viscosity guar gum, in the form of a matrix tablet was capable of protecting the drug from being released in the upper region of gastrointestinal (GI) system, i.e. stomach and small intestine. X-ray imaging technique was used to monitor the tablets throughout the GI system on 8 healthy volunteers. Barium sulphate was used as a marker in the tablets for in vivo studies. These results showed that, the matrix tablets reached the colon; not being subjected to disintegration in the upper region of the GI system in all the subjects.

Review article: 5-aminosalicylate formulations for the treatment of ulcerative colitis--methods of comparing release rates and delivery of 5-aminosalicylate to the colonic mucosa

BACKGROUND

Many oral 5-aminosalicylic acid (5-ASA) formulations are designed to maximize 5-ASA release in the colon where it acts topically on the colonic mucosa. Delayed-release formulations and azo-prodrugs minimize 5-ASA absorption in the upper gastrointestinal (GI) tract.

AIMS

To review methods for assessing 5-ASA release and colonic distribution from oral formulations, and the potential use of this information for guiding clinical decisions.

METHODS

PubMed and recent conference abstracts were searched for articles describing techniques used to assess 5-ASA release from ulcerative colitis (UC) therapies.

RESULTS

In-vitro GI models, although unable to simulate more complex aspects of GI physiology, can provide useful data on 5-ASA release kinetics and bioaccessibility. Gamma-scintigraphy is useful for investigating GI disintegration of different formulations, but may not accurately reflect 5-ASA distribution. Plasma pharmacokinetic studies provide data on systemic exposure, but not on colonic distribution or mucosal uptake. Mucosal biopsies provide direct evidence of colonic distribution and may predict clinical efficacy, but must be interpreted cautiously because of considerable inter-subject variability and other confounding factors.

CONCLUSION

While assessment of 5-ASA release is important, limitations of individual measurement techniques mean that randomized clinical studies in UC patients remain the best guide for dosing and treatment regimen decisions.

Intestinal antiinflammatory effect of 5-aminosalicylic acid is dependent on peroxisome proliferator-activated receptor-gamma

5-aminosalicylic acid (5-ASA) is an antiinflammatory drug widely used in the treatment of inflammatory bowel diseases. It is known to inhibit the production of cytokines and inflammatory mediators, but the mechanism underlying the intestinal effects of 5-ASA remains unknown. Based on the common activities of peroxisome proliferator–activated receptor-γ (PPAR-γ) ligands and 5-ASA, we hypothesized that this nuclear receptor mediates 5-ASA therapeutic action. To test this possibility, colitis was induced in heterozygous PPAR-γ^+/− mice and their wild-type littermates, which were then treated with 5-ASA. 5-ASA treatment had a beneficial effect on colitis only in wild-type and not in heterozygous mice. In epithelial cells, 5-ASA increased PPAR-γ expression, promoted its translocation from the cytoplasm to the nucleus, and induced a modification of its conformation permitting the recruitment of coactivators and the activation of a peroxisome-proliferator response element–driven gene. Validation of these results was obtained with organ cultures of human colonic biopsies. These data identify PPAR-γ as a target of 5-ASA underlying antiinflammatory effects in the colon.

A double-blind dose-escalating trial comparing novel mesalazine pellets with mesalazine tablets in active ulcerative colitis

BACKGROUND

Mesalazine as the treatment standard for ulcerative colitis can be applied in different galenical preparations.

AIM

A novel formulation of mesalazine pellets with delayed and prolonged release characteristics was compared with conventional Eudragit L-coated tablets. Furthermore, the effect of mesalazine dose escalation on nonresponders was evaluated in both treatment groups.

METHODS

A total of 233 patients with mild to moderately active ulcerative colitis were randomized to receive either mesalazine (1.5 g/day in three doses) as pellets (n = 115) or tablets (n = 118) for 8 weeks. At insufficient response, the dose was increased to 3.0 g.

RESULTS

The clinical remission rate (clinical activity index < or = 4) for pellets was 67% vs. 68% for tablets which statistically proved to be not inferior (significance level alpha = 2.5%). In patients without dose increase, the remission rate was 47% (pellets) vs. 42% (tablets). Endoscopic improvement was observed in 80% (pellets) vs. 83% (tablets), and histological improvement in 48% (pellets) vs. 52% (tablets) of patients.

CONCLUSIONS

Mesalazine pellets are as effective as tablets in the treatment of mild to moderately active ulcerative colitis. Dose escalation to 3.0 g/day is a valid option for nonresponders to a starting dose of 1.5 g/day.

Effect of 5-aminosalicylic acid on radiation-induced micronuclei in mouse bone marrow

5-Aminosalicylic acid (5ASA), a prescribed drug for ulcerative colitis, is a potent scavenger of oxygen-derived free radicals. The present study was undertaken to ascertain its ability to protect against radiation-induced damage. The drug dose-dependent effect, optimum time of drug administration and radiation dose-dependent effect (0-4 Gy) on in vivo radiation protection against micronuclei induction in polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE) were studied in the bone marrow of mice. Intraperitoneal injection of 10-125 mg/kg of the drug 30 min before whole body irradiation with 3 Gy produced a significant reduction in the frequency of micronucleated erythrocytes at 24 h after exposure. The optimum dose for protection without drug toxicity was 25 mg/kg body weight. Injection of 25 mg/kg of the drug 60 or 30 min before or within 15 min after 3 Gy whole body gamma-irradiation resulted in a significant decrease in the radiation-induced PCE and NCE with micronuclei (MPCE and MNCE) and an increase in the ratio of PCE to NCE (P/N), at 24 h post-irradiation. Maximum effect was seen when the drug was administered 30 min before irradiation. Therefore, to study the radiation dose-response, mice were pre-treated with 25 mg/kg of 5ASA 30 min before 1-4 Gy of gamma-irradiation. Radiation increased the MN frequency linearly (r(2)=0.99) with dose. Pre-treatment with 5ASA significantly reduced the MN counts to 40-50% of the radiation (RT) alone values, giving a dose modification factor (DMF) of 2.02 (MPCE) and 2.53 (MNCE). Irradiation resulted in a dose-dependent decline in the P/N ratio at all the doses of radiation studied. 5ASA produced a significant increase in the P/N ratio from that of irradiated controls, at all doses of radiations tested. These results show that 5ASA protect mice against radiation-induced MN formation and mitotic arrest.

Combined scintigraphic and pharmacokinetic investigation of enteric-coated mesalazine micropellets in healthy subjects

BACKGROUND

There is a growing clinical trend to increase the daily dose of mesalazine, which leads to significant compliance issues associated with multiple dosings of current preparations.

AIM

To examine the gastrointestinal performance and systemic exposure of a 1.5 g sachet (micropellets) mesalazine formulation, compared with three enteric-coated tablets (500 mg each, Claversal).

METHODS

A randomized, two-way, cross-over pharmacoscintigraphic (scintigraphy plus pharmacokinetics) study and a two-way, cross-over, pharmacokinetic-only study were performed in 24 healthy volunteers (12 subjects per investigation).

RESULTS

The relative bioavailability of mesalazine was 92% comparing micropellets with Claversal tablets, and the cumulative urine excretion was c. 26% for both preparations, suggesting comparable systemic exposure for the two types of preparation. In the majority of subjects, drug release from the micropellet formulation occurred predominantly in the terminal ileum and ascending colon. The Claversal tablets disintegrated in comparable intestinal sites, albeit at slightly later time points than the micropellets, principally due to slower gastric emptying for the single-unit formulation.

CONCLUSION

The 1.5 g micropellet formulation offers comparable delivery properties to the marketed tablets, but with greater convenience of dosing.

Bioequivalence testing for locally acting gastrointestinal products: what role for gamma scintigraphy?

Bioequivalence testing for locally acting gastrointestinal products is a challenging issue for both the pharmaceutical industry and the global regulatory authorities. It is widely accepted that for medicinal products not intended to be delivered into the systemic circulation, pharmacokinetic bioavailability cannot be used. However, it is becoming increasingly accepted that local availability may be assessed, where appropriate, by approaches that qualitatively reflect the presence of the active substance at the site of action. These methods must be specifically chosen for that combination of active substance and route of drug delivery. This paper argues for the use of gamma scintigraphy as a validated measure of local availability and bioequivalence for topically acting products administered to the gastrointestinal tract by the oral and rectal route.

Pharmacokinetic considerations in the treatment of inflammatory bowel disease

This review describes the pharmacokinetics of the major drugs used for the treatment of inflammatory bowel disease. This information can be helpful for the selection of a particular agent and offers guidance for effective and well tolerated regimens. The corticosteroids have a short elimination half-life (t1/2beta) of 1.5 to 4 hours, but their biological half-lives are much longer (12 to 36 hours). Most are moderate or high clearance drugs that are hepatically eliminated, primarily by cytochrome P450 (CYP) 3A4-mediated metabolism. Prednisone and budesonide undergo presystemic elimination. Any disease state or comedication affecting CYP3A4 activity should be taken into account when prescribing corticosteroids. Depending on the preparation used, 10 to 50% of an oral or rectal dose of mesalazine is absorbed. Rapid acetylation in the intestinal wall and liver (t1/2beta 0.5 to 2 hours) and transport probably by P-glycoprotein affect mucosal concentrations of mesalazine, which apparently determine clinical response. Any clinical condition influencing the release and topical availability of mesalazine might modify its therapeutic potential. Metronidazole has high (approximately 90%) oral bioavailability, with hepatic elimination characterised by a t1/2beta of 6 to 10 hours and a total clearance of about 4 L/h/kg. Ciprofloxacin is largely excreted unchanged both renally (about 45% of dose) and extrarenally (25%), with a relatively short t1/2beta (3.5 to 7 hours). Thus, renal function affects the systemic availability of ciprofloxacin. Both mercaptopurine and its prodrug azathioprine are metabolised to active compounds (6-thioguanine nucleotides; 6-TGN) by hypoxanthine-guanine phosphoribosyltransferase and to inactive metabolites by the polymorphically expressed thiopurine S-methyltransferase (TPMT) and xanthine oxidase. Patients with low TPMT activity have a higher risk of developing haemopoietic toxicity. Both mercaptopurine and azathioprine have a short t1/2beta (1 to 2 hours), but the t1/2beta of 6-TGN ranges from 3 to 13 days. Therapeutic response seems to be related to 6-TGN concentration. Almost complete bioavailability has been observed after intramuscular and subcutaneous administration of methotrexate, which is predominantly (85%) excreted as unchanged drug with a t1/2beta of up to 50 hours. Thus, renal function is the major determinant for disposition of methotrexate. Cyclosporin is slowly and incompletely absorbed. It is extensively metabolised by CYP3A4/5 in the liver and intestine (median t1/2beta and clearance 7.9 hours and 0.46 L/h/kg, respectively), and inhibitors and inducers of CYP3A4 can modify response and toxicity. Infliximab is predominantly distributed to the vascular compartment and eliminated with a t1/2beta between 10 and 14 days. No accumulation was observed when it was administered at intervals of 4 or 8 weeks. Methotrexate may reduce the clearance of infliximab from serum.

Mono- and biphasic plasma concentration-time curves of mesalazine from a 500 mg suppository in healthy male volunteers controlled by the time of defecation before dosing

This study was based on data from a bioequivalence study (n=24) of two different formulations of suppositories containing 500 mg mesalazine (formulation I and II), with a similar dissolution profile in phosphate buffer pH 6.8. There was a large intra- and intersubject variability in the plasma concentration-time curves of mesalazine from both suppositories. The aim of the investigation was to identify the parameters that caused the observed large variations in release and absorption of mesalazine in the rectum. Plasma mesalazine and acetylmesalazine, and urine acetylmesalazine concentrations were determined according to validated methods involving HPLC analysis with coulometric detection. Lower limit of quantitation values were respectively 10.4 and 19.4 ng mL(-1) in plasma and 0.96 microg mL(-1) in urine. The time of defecation before and after insertion was recorded. There was a clear distinction between subjects who showed monophasic mesalazine release/absorption and those who showed biphasic and more extended release/absorption. With formulation I there was a correlation between time of defecation before dosing and the type of absorption, monophasic and biphasic absorbers showed a significant difference in the time of defecation, e.g. 9.7+/-5.6 h vs 18.8+/-11.9 h (P = 0.0218). The impact of time of defecation before dosing was non-significant with formulation II, 16.7+/-7.2 h vs 15.1+/-4.2 h (P = 0.67). The impact of the time elapsed between administration and time of defecation after the insertion of the suppository was not significant for the type of release/absorption. The plasma concentration-time curves of the metabolite ran parallel to that of the parent drug, the more parent drug was released/absorbed, the more was acetylated (P = 0.0013) and excreted into the urine (P = 0.0004). After absorption the compound was metabolized into acetylmesalazine, and renally excreted (12-13% of the dose). Monophasic release/ absorption resulted in 7.1% metabolite with I and 10.3% with II (P = 0.0004), while biphasic release/absorption gave 16.8% metabolite with I and 15.5% with II. The renal clearance of the metabolite acetylmesalazine was independent of the observed defecation patterns (300 mL min(-1), P > 0.8), stool composition, and type of absorption.

Gastrointestinal spread of oral prolonged-release mesalazine microgranules (Pentasa) dosed as either tablets or sachet

BACKGROUND

There is increasing interest in using higher dosages of mesalazine for the treatment of inflammatory bowel disease; however, with current mesalazine products this involves the use of 8-16 tablets per day.

AIM

To evaluate the disposition, dispersion and movements of Pentasa prolonged-release microgranules following single dosing of either tablets (2 x 500 mg) or a new 1 g sachet (unit dose, microgranules in a foil bag).

METHODS

A randomized crossover study in eight healthy volunteers was undertaken. Both formulations were radiolabelled by neutron activation and dosed in the fasted state. Location of the preparations in the bowel was assessed over 24 h by scintigraphy.

RESULTS

Dissolution testing at pH 7.5 showed comparable in vitro mesalazine release properties for the tablet and sachet preparations. In vivo disposition of the microgranules administered as either tablets or sachet was comparable in terms of gastric emptying, small intestinal transit and colon arrival.

CONCLUSIONS

Pentasa sachets 1 g unit dose offers the same release of mesalazine as Pentasa 500 mg tablets. Drug release occurs throughout the gastrointestinal tract from stomach to colon, with the advantage of fewer oral doses and ease of swallowing.

Prevention of post-operative recurrence of Crohn's disease requires adequate mucosal concentration of mesalazine. Gruppo Italiano per lo Studio del Colon e del Retto

BACKGROUND

Surgical resection of Crohn's disease is followed by early recurrence in a high percentage of patients. Mesalazine has been shown to be effective in the prevention of post-operative recurrence, but some 50% of patients under treatment recur at 3 years of follow-up.

AIM

To establish whether the mucosal concentration of mesalazine might affect the development of post-operative recurrence.

METHODS

Colon-ileoscopy was performed in 25 consecutive patients resected for Crohn's disease. The mean time from surgery was 14 months. After the operation, all patients were taking oral mesalazine (Asacol, 2.4 g/day). Ten patients showed signs of endoscopic recurrence (apthae, ulcers, narrowing of the lumen) in the neoterminal ileum, five of whom also showed juxta-anastomotic colonic involvement. Fifteen patients were free of recurrence. At endoscopy, four biopsies were taken from the perianastomotic area (two specimens at the ileal site and two specimens at the colonic site of the anastomosis). The specimens were weighed and immediately frozen at -80 degrees C. Mesalazine concentration (ng/mg) was measured in tissue homogenates by high- performance liquid chromatography with electrochemical detection. Fisher's exact test was used for the statistical analysis.

RESULTS

The mean value of mucosal mesalazine concentration, expressed as ng/mg of tissue, was significantly lower in patients with recurrence than in those without recurrence both in the ileum (mean +/- s.d.: 21.6+/-28.3 vs. 70.9+/-47.4; P = 0.007) and in the colon (25.8+/-26.4 vs. 60.3+/-32.5; P = 0.010).

CONCLUSIONS

The mucosal concentration of mesalazine in the juxta-anastomatic area is significantly lower in patients with recurrence than in those free of recurrence. These data could suggest an association between mucosal mesalazine concentrations and the clinical effectiveness of the drug.

[Pharmacokinetic data for different 5-aminosalicylic acid and budesonide preparations]

Different orally and rectally applicable forms of 5-ASA and budesonide have been developed to achieve sufficient high concentrations of the active moieties at the site of inflammation (small and/or large bowel) and to limit the systemic action of the drugs. This concept of drug targeting could be accomplished by both special galenic formulations and by utilizing the pharmacokinetic properties of the agents especially their high intestinal and hepatic presystemic elimination. Thus, 5-ASA and budesonide represent drugs of first choice in the treatment of Crohn's disease and ulcerative colitis. This review describes the various pharmacokinetic and (patho)physiologic factors and their impact on drug delivery and biological availability of the different 5-ASA and budesonide preparations.

Review article: Drug development in inflammatory bowel disease: budesonide--a model of targeted therapy

The use of non-specific anti-inflammatory drugs such as the glucocorticoids is the foundation of medical therapy for inflammatory bowel disease. Although conventional steroid drugs are highly effective, their use is associated with the adverse effects of Cushing's syndrome. However, the therapeutic index of these drugs can be improved by chemical modification of the steroid nucleus and the use of new drug delivery systems that target the bowel wall as the pharmacokinetic compartment of interest. Budesonide is a novel glucocorticoid compound that illustrates the potential of this approach to identify effective and safe new treatments. Regional therapy for inflammatory bowel disease is an important pharmacological concept for the future development of the new glucocorticoids and other classes of drugs.

Mesalamine-induced hypersensitivity pneumonitis. A case report and review of the literature

A 49-year-old man with Crohn's disease treated with prednisone and mesalamine (5-ASA) developed worsening respiratory distress and fever. Symptoms improved after discontinuation of mesalamine. A rechallenge 3 months later caused similar pulmonary symptoms, confirming the association between the drug and the respiratory system. Mesalamine may cause hypersensitivity pneumonitis in patients with Crohn's disease.

Delivery and fate of oral mesalamine microgranules within the human small intestine

BACKGROUND/AIMS

Oral use of mesalamine in inflammatory bowel disease requires slow-release preparations to prevent premature absorption and inactivation. Resulting luminal concentrations within the human small intestine are unknown. The aim of this study was to determine human intestinal delivery patterns of mesalamine from a microgranule preparation (Pentasa; Ferring Arzeimittel, Kiel, Germany) effective in Crohn's disease with small bowel involvement.

METHODS

A multilumen tube for duodenal, jejunal, and ileal aspiration and marker perfusion was placed in 6 normal subjects. Levels of luminal, plasma, and urinary mesalamine and its main metabolite, acetyl mesalamine, were measured for 7 hours after ingestion of mesalamine (500 mg) with a labeled meal.

RESULTS

Gastric emptying of mesalamine paralleled the meal, and its release occurred throughout the small intestine (cumulative, 20% of dose). For 4 hours, mean luminal mesalamine and acetyl mesalamine concentrations were 52 and 38 micrograms/mL (duodenum), 59 and 82 micrograms/mL (jejunum), and 64 and 104 micrograms/mL (ileum). Cumulative colonic delivery was 82% (7% dissolved, 75% in microgranules), and urinary excretion was 3.5%.

CONCLUSIONS

Although the major part of continuous-release mesalamine is delivered to the colon, large proportions are liberated and available at high concentrations within the small intestinal lumen, thus explaining its therapeutic efficacy in small intestinal Crohn's disease.

The management of ulcerative colitis

The treatment of ulcerative colitis (UC) remains empiric because of undetermined etiology and pathogenesis and incomplete understanding of the underlying immunoinflammatory events. However, considerable progress has been made in the management of this disease with the availability and wider use of newer aminosalicylates and immunomodulating agents. The clinician confronted with a patient with chronic ulcerative colitis must weigh the advantages of continued medical therapy against the potential curability with improved surgical techniques. After a brief discussion of the current classes of medicines and their pathophysiological basis of action, we focus on standard approaches to the different clinical syndromes and their complications.