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

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.

Sustained release of 5-aminosalicylic acid from azoreductase-responsive polymeric prodrugs for prolonged colon-targeted colitis therapy

Ulcerative colitis (UC) is a challenging inflammatory gastrointestinal disorder, whose therapies encounter limitations in overcoming insufficient colonic retention and rapid systemic clearance. In this study, we report an innovative polymeric prodrug nanoformulation for targeted UC treatment through sustained 5-aminosalicylic acid (5-ASA) delivery. Amphiphilic polymer-based 13.5 nm micelles were engineered to incorporate azo-linked 5-ASA prodrug motifs, enabling cleavage via colonic azoreductases. In vitro, micelles exhibited excellent stability under gastric/intestinal conditions while demonstrating controlled 5-ASA release over 24 h in colonic fluids. Orally administered micelles revealed prolonged 24-h retention and a high accumulation within inflamed murine colonic tissue. At an approximately 60% dose reduction from those most advanced recent studies, the platform halted DSS colitis progression and outperformed standard 5-ASA therapy through a 77-97% suppression of inflammatory markers. Histological analysis confirmed intact colon morphology and restored barrier protein expression. This integrated prodrug nanoformulation addresses limitations in colon-targeted UC therapy through localized bioactivation and tailored pharmacokinetics, suggesting the potential of nanotechnology-guided precision delivery to transform disease management.

Electroanalytical Overview: The Sensing of Mesalamine (5-Aminosalicylic Acid)

Mesalamine, known as 5-aminosalicylic acid, is a medication used primarily in the treatment of inflammatory bowel disease, including ulcerative colitis and Crohn's disease. 5-Aminosalicylic acid can be measured using various benchtop laboratory techniques which involve liquid chromatography-mass spectroscopy, but these are sophisticated and large, meaning that they cannot be used on-site because transportation of the samples, chemicals, and physical and biological reactions can potentially occur, which can affect the sample's composition and potentially result in inaccurate results. An alternative approach is the use of electrochemical based sensing platforms which has the advantages of portability, cost-efficiency, facile miniaturization, and rapid analysis while nonetheless providing sensitivity and selectivity. We provide an overview of the use of the electroanalytical techniques for the sensing of 5-aminosalicylic acid and compare them to other laboratory-based measurements. The applications, challenges faced, and future opportunities for electroanalytical based sensing platforms are presented in this review.

Mucoadhesive Hydrogel with Anti-gastric Acid and Sustained-Release Functions for Amelioration of DSS-Induced Ulcerative Colitis

Mucoadhesive hydrogels with multifunctional properties such as gastric acid resistance and sustained drug release in the intestinal tract are highly desirable for the oral treatment of inflammatory bowel diseases (IBDs). Polyphenols are proven to have great efficacies compared with the first-line drugs for IBD treatments. We recently reported that gallic acid (GA) was capable of forming a hydrogel. However, this hydrogel is prone to easy degradation and poor adhesion in vivo. To tackle this problem, the current study introduced sodium alginate (SA) to form a gallic acid/sodium alginate hybrid hydrogel (GAS). As expected, the GAS hydrogel showed excellent antiacid, mucoadhesive, and sustained degradation properties in the intestinal tract. In vitro studies demonstrated that the GAS hydrogel significantly alleviated ulcerative colitis (UC) in mice. The colonic length of the GAS group (7.75 ± 0.38 cm) was significantly longer than that of the UC group (6.12 ± 0.25 cm). The disease activity index (DAI) value of the UC group was (5.5 ± 0.57), which was markedly higher than that of the GAS group (2.5 ± 0.65). The GAS hydrogel also could inhibit the expression of inflammatory cytokines, regulating macrophage polarization and improving the intestinal mucosal barrier functions. All these results indicated that the GAS hydrogel was an ideal candidate for oral treatment of UC.

Factors associated with the persistence of oral 5-aminosalicylic acid monotherapy in ulcerative colitis: a nationwide Norwegian cohort study

BACKGROUND

Oral 5-aminosalicylic acid (5-ASA) is the mainstay treatment of ulcerative colitis (UC) and therapy with oral 5-ASA is associated with beneficial outcomes. We have examined factors associated with the persistence of oral 5-ASA treatment in a national cohort of UC patients.

METHODS

Patients with newly diagnosed UC from 2010 to 2014 using oral 5-ASA monotherapy were identified by combining data from the Norwegian Patient Registry and the Norwegian Prescription Database. The median follow-up time was 1029 days. Drug persistence was defined as duration of oral 5-ASA preparation as monotherapy. Non-persistence of a oral 5-ASA preparation as monotherapy was defined as stopping oral 5-ASA, initiation of any further anti-inflammatory treatment including a course of glucocorticoids and a change to another oral 5-ASA preparation. Drug persistence was analyzed using the Kaplan-Meier method and influence of covariates on drug persistence was analyzed with the Cox proportional hazard model.

RESULTS

A total of 3421 patients were identified. The overall median 5-ASA drug persistence was 179 days. In univariate analyses, persistence was associated with preparation type and high-dose treatment, while oral glucocorticoid use or hospitalization around the start of oral 5-ASA were associated with shorter 5-ASA persistence. In multivariate analyses, oral glucocorticoids [HR 1.67 (1.54-1.80), p < 0.005] and hospitalization around start of 5-ASA [HR 1.23 (1.14-1.34), p < 0.005] were associated with non-persistence, whereas high dose (⩾3 g/day) 5-ASA was associated with longer persistence [HR 0.68 (0.65-0.71), p < 0.005].

CONCLUSION

High-dose treatment with oral 5-ASA was associated with longer persistence of oral 5-ASA monotherapy, whereas the presence of factors indicating more severe disease around initiation of 5-ASA monotherapy was associated with a shorter persistence.

Recent advances in mesalamine colonic delivery systems

Background

Increased attention has been focused on the continuous development and improvement of mesalamine colonic specific delivery systems, for the effective treatment of inflammatory bowel diseases; thus enhancing therapeutic efficacy and reducing potential side effects. Mesalamine is a class IV drug, according to the Biopharmaceutics Classification System, used usually to treat inflammation associated with colon related diseases such as Crohn’s disease and ulcerative colitis.

Main text

An ideal colon targeting system aims to deliver a therapeutic agent, selectively and effectively, to the colon. This system should ideally retain the drug release in the upper GI tract (stomach and small intestine); while trigger the drug release in the colon. Several approaches have been used to fabricate formulations to achieve a colon specific delivery of mesalamine such as; time dependent, pH responsive, enzymatic/microbial responsive and ultrasound mediated approaches. This overview outlines the recent advances in mesalamine-colon delivery approaches for the potential treatment of ulcerative colitis and Crohn’ disease.

Conclusion

A combined pH-time dependent delivery system can improve mesalamine colonic drug delivery via employing carriers capable of retarding mesalamine release in the stomach and delivering it at predetermined time points after entering the intestine. The existence of specific enzymes, produced by various anaerobic bacteria present in the colon advocates the advantage of designing enzyme sensitive systems and combining it with pH-time dependent system to improve mesalamine colonic delivery. The use of ultrasound has shown promises to effectively treat inflammatory bowel diseases.

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.

Interplay between Cellular and Molecular Mechanisms Underlying Inflammatory Bowel Diseases Development-A Focus on Ulcerative Colitis

Inflammatory bowel diseases (IBD) are defined by the continuous inflammation of the gastrointestinal tract. During inflammation, the number of pathogens in the intestinal epithelium increases, leading to inflammasome assembly. Inflammasome activation is meant to protect the intestinal epithelial barrier from further damage by maintaining homeostasis. Although its purpose is to protect the cells, excessive nucleotide-binding oligomerization domain-like receptor and pyrin domain-containing protein 3 (NLRP3) inflammasome assembly is responsible for the synthesis of a high number of pro-inflammatory cytokines. The activation of two crucial pathways, autophagy process, and unfolded protein response, is initiated for restoring homeostasis. Aberrant expression of miRNAs and lncRNAs also interfere with the pathogenic mechanisms of IBD, as these non-coding transcripts play key roles in regulation of biological processes, such as inflammation and immunity. This review thoroughly describes the cellular and molecular mechanism that trigger and perpetuate inflammation in ulcerative colitis (UC) patients.

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

Ru^II-p-cymene complexes of imidazole–mesalazine based ligands kill bulk and stem colon cancer cells with tight regulation over stemness markers.

Effects of Differential Food Patterns on the Pharmacokinetics of Enteric-Coated Mesalazine Tablets in the Same Cohort of Healthy Chinese Volunteers

This study aimed to simultaneously determine mesalazine (5-ASA) and its major metabolite N-Ac-5-ASA in the plasma and to evaluate the impact of different food patterns on the relative bioavailability and pharmacokinetics of a single oral dose of 5-ASA in healthy subjects. In this single-dose, open-label, 3-period, 3-treatment crossover study, the subjects received a single, oral dose of 500-mg enteric-coated mesalazine tablet together with either a low-fat or a high-fat breakfast or under fasting condition (reference). The pharmacokinetic parameters were determined by noncompartmental methods and analyzed with a linear mixed-effect model. The geometric least squares mean ratio for the area under the plasma concentration-time curve from zero to infinity of N-Ac-5-ASA was 1.05 (90% confidence interval [CI], 0.70-1.58) for high-fat/fasted condition and 1.06 (90%CI, 0.82-1.36) for low-fat/fasted condition. The least squares mean ratio of 5-ASA was 0.86 (90%CI, 0.65-1.14) for high-fat/fasted condition and 0.78 (90%CI, 0.60-1.02) for low-fat/fasted condition. All P values were >.05. The mean maximum plasma concentration and the time to reach the maximum plasma concentration of N-Ac-5-ASA were 2084 ng/mL, 8 hours; 2639 ng/mL, 11 hours, and 2409 ng/mL, 9 hours for fasted, high-fat, and low-fat, respectively. The values of 5-ASA were 1950 ng/mL, 7 hours; 2869 ng/mL, 9 hours; and 2837 ng/mL, 8 hours for fasted, high-fat, and low-fat condition. 5-ASA was well tolerated under all 3 conditions. Food delayed the absorption of 5-ASA, especially a high-fat meal. Therefore, enteric-coated mesalazine tablets should be taken before meals to avoid causing patients slow response and any effect of food on its efficacy.

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.

Pharmacotherapy of ulcerative colitis - current status and emerging trends

Ulcerative colitis (UC) is a chronic mucosal inflammation of the large intestine restricted to the rectum and colon. Its clinical course follows an intermittent pattern with episodes of relapse, followed by remission and eventually resulting in mucosal damage. Although there is no permanent cure for UC, the currently available pharmacotherapy aims to induce and maintain clinical remission, promote the healing of colonic mucosa and avert any surgical intervention. The conventional drug therapy comprising of 5-aminosalicylates, thiopurines and corticosteroids has advanced recently in terms of formulations and dosing schedule, resulting in improved efficacy, safety and compliance. Calcineurin inhibitors, such as cyclosporin and tacrolimus, have emerged as steroid sparing agents. The treatment paradigm of UC patients who are refractory to conventional drugs has changed in view of the availability of biologics. Currently, there are four biologics approved by the US FDA for the treatment of UC, namely, infliximab, adalimumab, golimumab and vedolizumab, and several others are undergoing clinical trial. In this comprehensive review, the advantages and limitations of the medical therapy of UC are elaborated with an emphasis on the pharmacokinetic and pharmacodynamic aspects of the drugs.

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.

α-Mangostin ameliorates dextran sulfate sodium-induced colitis through inhibition of NF-κB and MAPK pathways

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) of the colon as a target site. Previous reports regarding the efficacy of α-mangostin (αMG) to inhibit nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs) as well as relatively high distribution to the colon suggested the therapeutic potential of this compound in UC model. In dextran sodium sulfate (DSS)-induced colitis mice (DSS mice), the disease activity index scores involving diarrhea, bloody stool, body weight reduction, and myeloperoxidase (MPO) activities of the esophagus and colon increased with the reduced colon length. Also histologic disturbances and changes of NF-κB and MAPK pathways including phosphorylation of IκB kinase, ERK1/2, SAPK/JNK and p38 were observed in the colon of the DSS mice. However, all of these impaired conditions in the DSS mice were restored by αMG treatment, and the intestinal metabolism of αMG decreased, increasing its distribution to the colons in the DSS mice compared with the control mice. All of these results suggest that high distribution of αMG in the colon might attenuate DSS-induced colitis by inhibiting NF-κB and MAPK pathways in the colon.

Mucoadhesive chitosan hydrogels as rectal drug delivery vessels to treat ulcerative colitis

Mucoadhesive drug delivery systems stick to mucosal tissues and prolong the local retention time of drugs. Since the colon is covered by a mucosal layer, mucoadhesive rectal formulations may improve treatment of such diseases as hypertension or colon cancer. Ulcerative colitis (UC) is an inflammatory bowel disease characterized by chronic inflammation of the colonic mucosa. It is commonly treated with sulfasalazine (SSZ), which is metabolized by the intestinal flora into the therapeutic 5-aminosalicylic acid (5-ASA) and a toxic by-product sulfapyridine (SP). SSZ can be administered orally or rectally. The latter route avoids unintended absorption of the drug or its degradation products in the upper gastrointestinal tract, but often fails due to limited retention time. Here, we propose a mucoadhesive hydrogel to improve the efficacy of rectal SSZ administration. The gel is made of catechol modified-chitosan (Cat-CS) crosslinked by genipin. After loading the gel with SSZ, we evaluated its efficacy in a mouse model of UC. Compared to oral SSZ treatment, rectal SSZ/Cat-CS delivery was more therapeutic, showed equivalent histological scores, and induced a lower plasma concentration of the potentially toxic SP by-product. These results show SSZ/Cat-CS rectal hydrogels are more effective and safer formulations for UC treatment than oral SSZ.

STATEMENT OF SIGNIFICANCE

Ulcerative colitis affects the colon by causing chronic inflammation on the mucosa. One of the most common drugs to treat mild to moderate UC is sulfasalazine, which can be administrated both orally and rectally. Rectal formulations are preferable, since their therapeutic effect happens topically, and they prevent side effects related to absorption of the drug in the small intestine. However, the efficacy of rectal sulfasalazine formulations is decreased by their limited colon residence time. Here we propose a chitosan-catechol mucoadhesive gel that allows delivering sulfasalazine more effectively and safely than oral administration. Our results bring new insights into the field of mussel-inspired catechol hydrogels, showing their potential as drug delivery systems to treat a widespread disease such as ulcerative colitis.

Structural landscape of multicomponent solids of 5-aminosalicylic acid

Crystallization of ten new multicomponent solids of 5-aminosalicylic acid with various inorganic and organic coformers has been achieved by mechanochemical and solvent evaporation techniques.

Mucoadhesive microparticulates based on polysaccharide for target dual drug delivery of 5-aminosalicylic acid and curcumin to inflamed colon

In this work, thiolated chitosan/alginate composite microparticulates (CMPs) coated by Eudragit S-100 were developed for colon-specific delivery of 5-aminosalicylic acid (5-ASA) and curcumin (CUR), and the use of it as a multi drug delivery system for the treatment of colitis. The physicochemical properties of the CMPs were evaluated. In vitro release was performed in gradually pH-changing medium simulating the conditions of different parts of GIT, and the results showed that the Eudragit S-100 coating has a pH-sensitive release property, which can avoid drug being released at a pH lower than 7. An everted sac method was used to evaluate the mucoadhesion of CMPs. Ex vivo mucoadhesive tests showed CMPs have excellent mucosa adhesion for the colonic mucosa of rats. In vivo treatment effect of enteric microparticulates systems was evaluated in colitis rats. The results showed superior therapeutic efficiency of this drug delivery system for the colitis rats induced by TNBS. Therefore, the enteric microparticulates systems combined the properties of pH dependent delivery, mucoadhesive, and control release, and could be an available tool for the treatment of human inflammatory bowel disease.

Dissolution of Commercially Available Mesalamine Formulations at Various pH Levels

Introduction

Mesalamine (5-aminosalicylic acid; 5-ASA) is recommended first-line therapy for mild-to-moderate ulcerative colitis. Many mesalamine formulations employ a pH-dependent release mechanism designed to maximize drug release in the colon. This study compared the in vitro release of 5-ASA from six commercially available mesalamine formulations at pH levels similar to those typically encountered in the human gastrointestinal tract.

Methods

The release of 5-ASA from six mesalamine formulations [Mesalazin-Kohlpharma (Kohlpharma, Germany), Mesalazin-Eurim (Eurimpharm, Germany), Mesalazina-Faes (Faes Farma, Spain), Mesalazine EC (Actavis B.V., Netherlands), Mesalazine EC 500 PCH (Pharmachemie B.V., Netherlands); multimatrix mesalamine (Shire US Inc., USA)] was monitored separately at three different pH levels [1.0 (2 h), 6.4 (1 h), and 7.2 (8 h)] using United States Pharmacopeia dissolution apparatus II. The dissolution percentage was calculated as a mean of 12 units for each formulation.

Results

At pH 1.0 and 6.4, <1 % of 5-ASA release was observed for each of the mesalamine formulations tested. At pH 7.2, complete release of 5-ASA occurred within 1 h for Mesalazine EC and Mesalazine EC 500 PCH, and within 2 h for Mesalazin-Kohlpharma, Mesalazin-Eurim, and Mesalazina-Faes; complete release of 5-ASA from multimatrix mesalamine occurred within 7 h. Little variability in rate of 5-ASA dissolution was observed between tablets of each formulation.

Conclusion

At pH 7.2, 5-ASA release profiles were variable among the commercially available mesalamine formulations that were tested.

In vitro biorelevant models for evaluating modified release mesalamine products to forecast the effect of formulation and meal intake on drug release

AIMS

Postprandial administration of solid oral dosage forms greatly changes the dissolution environment compared to fasted state administration. The aims of this study were to investigate and forecast the effect of co-administration of a meal on drug release for delayed and/or extended release mesalamine formulations as well as design of in vitro tests to distinguish among formulations in a biorelevant way.

METHODS

Five different mesalamine formulations (Asacol® 400 mg, Mezavant® 1200 mg, Pentasa® 500 mg and Salofalk® in the 250 mg and 500 mg strengths) were investigated with biorelevant dissolution methods using the USP apparatus III and USP apparatus IV (open loop mode) under both fasted and fed state conditions, as well as with the dissolution methods described in pharmacopeia for delayed and extended release mesalamine products.

RESULTS

Using the biorelevant experimental conditions proposed in this study, changes in release in the proximal gut due to meal intake are forecast to be minimal for Asacol®, Mezavant®, Pentasa® and Salofalk® 500 mg, while for Salofalk® 250 mg release was predicted to occur much earlier under fed state conditions. The USP apparatus III generally tended to result in faster dissolution rates and forecast more pronounced food effects for Salofalk® 250 mg than the USP apparatus IV. The biorelevant dissolution gradients were also able to reflect the in vivo behavior of the formulations.

CONCLUSIONS

In vitro biorelevant models can be useful in the comparison of the release behavior from different delayed and extended release mesalamine formulations as well as forecasting effects of concomitant meal intake on drug release.

Release of 5-Aminosalicylic Acid (5-ASA) from Mesalamine Formulations at Various pH Levels

Introduction

Oral formulations of 5-aminosalicylic acid (5-ASA) for treatment of ulcerative colitis have been developed to minimize absorption prior to the drug reaching the colon. In this study, we investigate the release of 5-ASA from available oral mesalamine formulations in physiologically relevant pH conditions.

Methods

Release of 5-ASA from 6 mesalamine formulations (APRISO^®, Salix Pharmaceuticals, Inc., USA; ASACOL^® MR, Procter & Gamble Pharmaceuticals UK Ltd.; ASACOL^® HD, Procter & Gamble Pharmaceuticals, USA; MEZAVANT XL^®, Shire US Inc.; PENTASA^®, Ferring Pharmaceuticals, Ltd., UK; SALOFALK^®, Dr. Falk Pharma UK Ltd.) was evaluated using United States Pharmacopeia apparatus I and II at pH values of 1.0 (2 h), 6.0 (1 h), and 6.8 (8 h). Dissolution profiles were determined for each formulation, respectively.

Results

Of the tested formulations, only the PENTASA formulation demonstrated release of 5-ASA at pH 1.0 (48%), with 56% cumulative release after exposure to pH 6.0 and 92% 5-ASA release after 6–8 h at pH 6.8. No other mesalamine formulation showed >1% drug release at pH 1.0. The APRISO formulation revealed 36% 5-ASA release at pH 6.0, with 100% release after 3 h at pH 6.8. The SALOFALK formulation revealed 11% 5-ASA release at pH 6.0, with 100% release after 1 h at pH 6.8. No 5-ASA was released by the ASACOL MR, ASACOL HD, and MEZAVANT XL formulations at pH 6.0. At pH 6.8, the ASACOL MR and ASACOL HD formulations exhibited complete release of 5-ASA after 4 and 2 h, respectively, and the MEZAVANT XL formulation demonstrated complete 5-ASA release over 6–7 h.

Conclusion

5-Aminosalicylic acid release profiles were variable among various commercially available formulations.

Funding

Shire Development LLC.

Electronic supplementary material

The online version of this article (doi:10.1007/s12325-015-0206-4) contains supplementary material, which is available to authorized users.

Five-aminosalicylic Acid: an update for the reappraisal of an old drug

Inflammatory bowel disease (IBD) comprises several conditions with chronic or recurring immune response and inflammation of the gastrointestinal apparatus, of which ulcerative colitis and Crohn's disease are the commonest forms. This disease has a significant prevalence and it is of an unknown aethiology. Five-aminosalicylic acid (5-ASA) and its derivatives are among the oldest drugs approved for the treatment of the IBD. In this review we reapprise aspects of 5-ASA mechanism of action, safety, and efficacy that in our opinion make it a valuable drug that can be fruitfully tailored in personalised treatments as a therapeutic option alongside other immune-modifying agents.

Long-term efficacy and safety of once-daily mesalazine granules for the treatment of active ulcerative colitis

In 1977, 5-aminosalicylic acid (5-ASA) was discovered as a therapeutically active moiety of sulfasalazine (SASP) and was launched for topical and oral therapy of ulcerative colitis (UC) in 1984. As a first-step, delivery systems had to be developed to protect 5-ASA against absorption in the upper gastrointestinal tract, resulting in different and competing strategies (azo compounds, controlled release, and pH-dependent release). In a second step, at the beginning of the new century, coinciding with the expiration of patent protection for the first 5-ASA formulations, two component composite release mechanisms (pH-dependent and controlled release) were developed. Furthermore, the drug was formulated as granules instead of tablets, allowing higher unit strengths compared with tablets. Neither Salofalk Granu-Stix^®, nor MMX 5-ASA, nor Pentasa^® granules have initially been developed for once-daily (OD) dosing. A review of the achievements of 20 years of 5-ASA development has demonstrated that 5-ASA has equal efficacy compared with SASP at best, that there are no measurable differences in efficacy between various 5-ASA preparations, and that in a group of patients tolerating SASP, adverse event profiles of SASP and 5-ASA did not differ significantly, with SASP being the far cheaper substance. Therefore, drug adherence came into focus as a new goal for improving UC therapy. Although adherence is a complex and multifactorial construct, a simple dosing schedule may contribute to higher drug adherence and better efficacy of treatment. Simultaneously, the US 5-ASA market, estimated to be worth US$1.4 billion, is expected to grow continuously. Naturally, this very competitive market is not only driven by scientific progress but also by commercial interests. Thus, patents for minor changes to the formulation may serve as protection against drug companies trying to launch generic versions. Randomized controlled trials performed on OD dosing in induction of remission have demonstrated that OD administration of 5-ASA is as effective as conventional dosing in mild to moderate active UC. The three 5-ASA products MMX, Salofalk^®, and Pentasa^® employed in those studies so far have not shown differences in efficacy between OD and conventional dosing. No differences regarding safety outcomes have been detected between OD and conventional dosing, including incidence of adverse events, serious adverse events, or withdrawal from treatment due to an adverse event. Although the majority of patients prefer OD dosing to conventional dosing, it was not possible to detect differences in adherence between OD and multiple dose regimens in the clinical trial setting. Well-designed and controlled large-scale community-based studies are necessary to further investigate and prove the point of improved long-term adherence and treatment efficacy in OD dosing.

Effects of jianpi herbal suppository on hemorheology and CD62p in patients with ulcerative colitis

OBJECTIVE

To compare the effects of a Chinese herbal suppository (Jianpi suppository) and Western Medicine (mesalazine) on hemorheology and CD62p in patients with ulcerative colitis (UC).

METHODS

In a randomized trial, 120 mild to moderate UC patients were randomly divided into two equal groups. The Jianpi suppository group used Chinese herbal suppository rectally, while the mesalazine group was treated with mesalazine tablets orally. Two 15-day courses of treatment were carried out in both groups. Changes in the hemorheology and CD62p indices in patients were observed.

RESULTS

The hemorheology and CD62p indices in the Jianpi suppository group decreased significantly more than those of the mesalazine group.

CONCLUSION

Jianpi suppository is effective in improving the hypercoagulability of UC patients, and therefore may be worth using in clinical practice.

Carboxymethyl starch and lecithin complex as matrix for targeted drug delivery: I. Monolithic mesalamine forms for colon delivery

For drugs expected to act locally in the colon, and for successful treatment, a delivery device is necessary, in order to limit the systemic absorption which decreases effectiveness and causes important side effects. Various delayed release systems are currently commercialized; most of them based on pH-dependent release which is sensitive to gastrointestinal pH variation. This study proposes a novel excipient for colon delivery. This new preparation consists in the complexation between carboxymethyl starch (CMS) and Lecithin (L). As opposed to existing excipients, the new complex is pH-independent, inexpensive, and easy to manufacture and allows a high drug loading. FTIR, X-ray, and SEM structural analysis all support the hypothesis of the formation of a complex. By minor variation of the excipient content within the tablet, it is possible to modulate the release time and delivery at specific sites of the gastrointestinal tract. This study opens the door to a new pH-independent delivery system for mesalamine targeted administration. Our novel formulation fits well with the posology of mesalamine, used in the treatment of Inflammatory Bowel Disease (IBD), which requires repeated administrations (1g orally four times a day) to maintain a good quality of life.

[Rescue therapy with sulfasalazine prior to immunosuppressive or biological agents in ulcerative colitis poorly controlled with mesalazine]

INTRODUCTION

In ulcerative colitis, aminosalicylates are the mainstay of maintenance therapy. Sulfasalazine was the first aminosalicylic used in the maintenance therapy of this disease. Later, mesalazine was preferred due to its supposedly better tolerability. However, recent studies indicate certain benefits of the use of sulfasalazine because of its possible superior effectiveness. The aim of this study was to determine whether patients with ulcerative colitis poorly controlled by mesalazine as maintenance therapy respond to sulfasalazine, thus avoiding the use of immunosuppressive or biological therapies.

METHODS

The Inflammatory Bowel Disease Clinic of the Ramón y Cajal Hospital maintains a database in which all drug exposures are registered. We selected patients poorly controlled with mesalazine who had received sulfasalazine as rescue maintenance therapy. We determined the percentage of patients poorly controlled with mesalazine who responded to sulfasalazine.

RESULTS

Of 415 patients with ulcerative colitis, 49 had been treated with sulfasalazine at some time. Of these, sulfasalazine was selected as an alternative therapy due to poor disease control with mesalazine. The median duration of mesalazine therapy until the switch was 20.8 months, with a median dose of 3.35 g/day. In 21 of the 31 patients (67.7%), sulfasalazine was able to control symptoms and maintain remission.

CONCLUSION

Despite the limitations of this study, we found that 67.7% of patients with ulcerative colitis poorly controlled with mesalazine responded to a switch to sulfasalazine. These patients would normally have progressed to immunosuppressive, biological or surgical treatments. This option merits further studies. Meanwhile sulfasalazine should not be forgotten in the management of ulcerative colitis.

Management of pediatric ulcerative colitis: joint ECCO and ESPGHAN evidence-based consensus guidelines

BACKGROUND AND AIMS

Pediatric ulcerative colitis (UC) shares many features with adult-onset disease but there are some unique considerations; therefore, therapeutic approaches have to be adapted to these particular needs. We aimed to formulate guidelines for managing UC in children based on a systematic review (SR) of the literature and a robust consensus process. The present article is a product of a joint effort of the European Crohn's and Colitis Organization (ECCO) and the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN).

METHODS

A group of 27 experts in pediatric IBD participated in an iterative consensus process including 2 face-to-face meetings, following an open call to ESPGHAN and ECCO members. A list of 23 predefined questions were addressed by working subgroups based on a SR of the literature.

RESULTS

A total of 40 formal recommendations and 68 practice points were endorsed with a consensus rate of at least 89% regarding initial evaluation, how to monitor disease activity, the role of endoscopic evaluation, medical and surgical therapy, timing and choice of each medication, the role of combined therapy, and when to stop medications. A management flowchart, based on the Pediatric Ulcerative Colitis Activity Index (PUCAI), is presented.

CONCLUSIONS

These guidelines provide clinically useful points to guide the management of UC in children. Taken together, the recommendations offer a standardized protocol that allows effective, timely management and monitoring of the disease course, while acknowledging that each patient is unique.

Strategies of targeting oral drug delivery systems to the colon and their potential use for the treatment of colorectal cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related death in both men and women. Often, surgical intervention remains the choice in treating CRC. Traditional dosage forms used for treating CRC deliver drug to wanted as well as unwanted sites of drug action resulting in several adverse side effects. Targeted oral drug delivery systems are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific delivery of a drug to colon increases its concentration at the target site, and thus requires a lower dose with reduced incidence of side effects. The major obstacle to be overcome for successful targeting of drug to colon through oral route is that drug absorption/degradation must be avoided in stomach and small intestine before the dosage form reaches colon. The review includes discussion of physiological factors that must be considered when targeting drugs directly to colorectal region, an outline on drugs used for treatment and prevention of CRC, and a brief description of various types of colon-targeted oral drug delivery systems. The focus is on the assessment of various formulation approaches being investigated for oral colon-specific delivery of drugs used in the treatment and prevention of CRC.

Mesalamine in the treatment and maintenance of remission of ulcerative colitis

Ulcerative colitis (UC) is a chronic disease of the GI tract that is characterized by mucosal inflammation in the colon. Mesalamine (mesalazine) is a 5-aminosalicylic acid compound that is the first-line treatment for patients with mild-to-moderate UC. There are multiple formulations of mesalamine available, primarily differentiated by their means of delivering active mesalamine to the colon. Mesalamine has been demonstrated in randomized controlled trials to induce both clinical response and remission, and maintain clinical remission, in these patients. It has few serious adverse effects and is generally well tolerated by patients. The main areas of uncertainty with use of mesalamine in patients with UC center on the optimal dose for induction of response, how to maintain patient adherence and the role of mesalamine in cancer chemoprophylaxis. Generic forms of mesalamine have yet to be approved by regulatory bodies in the USA.

Pros and cons of medical management of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory disease characterized by diffuse mucosal inflammation limited to the colon and rectum. Although a complete medical cure may not be possible, UC can be treated with medications that induce and maintain remission. The medical management of this disease continues to evolve with a goal to avoid colectomy and ultimately alter the natural history of UC. Emergence of antitumor necrosis factor-α (TNF-α) agents has expanded the medical armamentarium. 5-Aminosalicylates continue to be used in mild to moderate UC and corticosteroids are mainly used for induction of remission with immunomodulators (6-mercaptopurine/azathiopurine/methotrexate) being applied as steroid-sparing agents for maintenance therapy. Infliximab has been approved by the U.S. Food and Drug Administration and used in the treatment of moderate to severe UC; nevertheless, its use may be associated with significant adverse effects and have a negative impact on the postoperative course should the patients undergo restorative proctocolectomy. In addition, there is always a concern about patients' compliance to medical therapy, cost of medications, and risk for UC-associated dysplasia. The authors discuss the pros and cons of medications used in the treatment of UC.

Once daily, high-dose mesalazine controlled-release tablet for colonic delivery: optimization of formulation variables using Box-Behnken design

The aim of this work was to statistically optimize a novel high-dose, mesalazine colonic delivery matrix system, potentially suitable for once daily administration, using simple wet granulation method. A hydrophobic-hydrophilic polymeric blend was used to manipulate drug release. A three-factor, three-level Box-Behnken design was used to construct polynomial models correlating the dependent and independent variables. Independent formulation variables were the percentages of the hydrophilic polymer Carbopol® 940, hydrophobic polymer Eudragit® RS, and the superdisintegrant croscarmellose sodium. The cumulative percentages of drug released at 6, 10, and 14 h were selected as dependent variables and restricted to 7.5-22.5% (Y(1)), 42.5-57.5 % (Y(2)), and 72.5-87.5% (Y(3)), respectively. A second-order polynomial equation fitted to the data was used to optimize the independent formulation variables. Based on Box-Behnken experimental design, different mesalazine release profiles were obtained. The optimized formulation containing 5.72% Carbopol®, 9.77% Eudragit® RS, and 1.45% croscarmellose sodium was prepared according to the software determined levels. It provided a release profile which was very close to the targeted release profile, where the calculated values of f(1) and f(2) were 8.47 and 67.70, respectively, and followed zero-order release kinetics.

Twelve-month persistency with oral 5-aminosalicylic acid therapy for ulcerative colitis: results from a large pharmacy prescriptions database

BACKGROUND

Patients receiving 5-aminosalicylic acid (5-ASA) require long-term therapy to achieve good outcomes. Persistency (duration of time from initiation to discontinuation of therapy) is therefore an important consideration.

AIM

To evaluate persistency in patients receiving various oral 5-ASA formulations.

METHODS

This retrospective, 12-month, cohort study examined new-starter patients (any age and diagnosis) from a large United States pharmacy database who filled a prescription for oral 5-ASA [Lialda(®), Asacol(®), Pentasa(®) 250 or 500 mg, balsalazide (generic and Colazal(®)), and olsalazine (Dipentum(®))] between March and September 2007. Persistency was evaluated monthly on the basis of prescription refill rates.

RESULTS

Prescription and refill records were identified for 44,191 patients receiving oral 5-ASA. After 1 year, 20% of patients receiving Lialda were considered persistent and classified as continuing (refilling within a timeframe of up to twice the duration of the prescription), compared with 9% receiving Asacol, 7 (250 mg) and 10% (500 mg) receiving Pentasa, 10% receiving balsalazide, and 10% receiving Dipentum.

CONCLUSIONS

Overall persistency with oral 5-ASA therapy was low. However, patients receiving once-daily Lialda had significantly higher persistency after 1 year of treatment than patients receiving other oral 5-ASA therapies.

Conventional medical management of inflammatory bowel disease

Conventional therapies for ulcerative colitis and Crohn's disease (CD) include aminosalicylates, corticosteroids, thiopurines, methotrexate, and anti-tumor necrosis factor agents. A time-structured approach is required for appropriate management. Traditional step-up therapy has been partly replaced during the last decade by potent drugs and top-down therapies, with an accelerated step-up approach being the most appropriate in the majority of patients. When patients are diagnosed with CD or ulcerative colitis, physicians should consider the probable pattern of disease progression so that effective therapy is not delayed. This can be achieved by setting arbitrary time limits for administration of biological therapies, changing therapy from mesalamine in patients with active ulcerative colitis, or using rescue therapy for acute severe colitis. In this review, we provide algorithms with a time-structured approach for guidance of therapy. Common mistakes in conventional therapy include overprescription of mesalamine for CD; inappropriate use of steroids (for perianal CD, when there is sepsis, or for maintenance); delayed introduction or underdosing with azathioprine, 6-mercaptopurine, or methotrexate; and failure to consider timely surgery. The paradox of anti-tumor necrosis factor therapy is that although it too is used inappropriately (when patients have sepsis or fibrostenotic strictures) or too frequently (for diseases that would respond to less-potent therapy), it is also often introduced too late in disease progression. Conventional drugs are the mainstay of current therapy for inflammatory bowel diseases, but drug type, timing, and context must be optimized to manage individual patients effectively.

Review article: delivery and efficacy of topical 5-aminosalicylic acid (mesalazine) therapy in the treatment of ulcerative colitis

BACKGROUND

The use of topical therapy in the treatment of ulcerative colitis has declined in recent years despite evidence of good efficacy.

AIMS

To review US prescription trends for 5-aminosalicylic acid (5-ASA) since the US approval of Asacol extended-release oral mesalazine (mesalamine) in 1992; to estimate the optimal level of 5-ASA exposure in the distal colon; to determine factors influencing distal colonic exposures; and to compare the effectiveness of different 5-ASA formulations (oral, topical suspension, foam, suppositories) in clinical trials.

METHODS

Review of clinical trials, physiologic studies and prescription trends of various mesalazine formulations for treatment of distal ulcerative colitis.

RESULTS

Between 1992 and 2009, prescriptions for oral mesalazine increased sixfold, whereas topical suspensions declined by 10%. In clinical trials, topical therapy resulted in higher remission and clinical response rates than oral therapy, with trends to earlier improvement. The mucosal concentrations of 5-ASA achieved by topical agents in the distal colon were up to 200-fold higher than those achieved by oral administration alone. Despite active colitis, over 40% of a topically administered 4 g 5-ASA suspension (equal to 1.6 g) reached the sigmoid colon. This likely represents a therapeutic exposure of 5-ASA. Although topical therapies are less convenient than oral medications, treatment algorithms have failed to take into account quality of life improvements resulting from more rapid and complete treatment response.

CONCLUSIONS

Topical mesalazine therapy is superior to oral therapy in distal ulcerative colitis for both therapeutic response and drug delivery. Practice patterns should be re-evaluated in light of this information.

Drug metabolome of the simvastatin formed by human intestinal microbiota in vitro

The human colon contains a diverse microbial population which contributes to degradation and metabolism of food components. Drug metabolism in the colon is generally poorly understood. Metabolomics techniques and in vitro colon models are now available which afford detailed characterization of drug metabolites in the context of colon metabolism. The aim of this work was to identify novel drug metabolites of Simvastatin (SV) by using an anaerobic human in vitro colon model at body temperature coupled with systems biology platform, excluding the metabolism of the host liver and intestinal epithelia. Comprehensive two-dimensional gas chromatography with a time-of-flight mass spectrometry (GC×GC-TOFMS) was used for the metabolomic analysis. Metabolites showing the most significant differences in the active faecal suspension were elucidated in reference with SV fragmentation and compared with controls: inactive suspension or buffer with SV, or with active suspension alone. Finally, time courses of selected metabolites were investigated. Our data suggest that SV is degraded by hydrolytic cleavage of methylbutanoic acid from the SV backbone. Metabolism involves demethylation of dimethylbutanoic acid, hydroxylation/dehydroxylation and β-oxidation resulting in the production of 2-hydroxyisovaleric acid (3-methyl-2-hydroxybutanoic acid), 3-hydroxybutanoic acid and lactic acid (2-hydroxypropanoic acid), and finally re-cyclisation of heptanoic acid (possibly de-esterified and cleaved methylpyranyl arm) to produce cyclohexanecarboxylic acid. Our study elucidates a pathway of colonic microbial metabolism of SV as well as demonstrates the applicability of the in vitro colon model and metabolomics to the discovery of novel drug metabolites from drug response profiles.

Clinical pharmacology of 5-ASA compounds in inflammatory bowel disease

Mesalamine has been the first-line of therapy in patients with inflammatory bowel disease (IBD) since the 1960s. This article serves as a review of the different 5-aminosalicylic acid compounds, release formulations, use and dosing in the treatment of IBD, in particular ulcerative colitis.

Reaction mechanism of azoreductases suggests convergent evolution with quinone oxidoreductases

Azoreductases are involved in the bioremediation by bacteria of azo dyes found in waste water. In the gut flora, they activate azo pro-drugs, which are used for treatment of inflammatory bowel disease, releasing the active component 5-aminosalycilic acid. The bacterium P. aeruginosa has three azoreductase genes, paAzoR1, paAzoR2 and paAzoR3, which as recombinant enzymes have been shown to have different substrate specificities. The mechanism of azoreduction relies upon tautomerisation of the substrate to the hydrazone form. We report here the characterization of the P. aeruginosa azoreductase enzymes, including determining their thermostability, cofactor preference and kinetic constants against a range of their favoured substrates. The expression levels of these enzymes during growth of P. aeruginosa are altered by the presence of azo substrates. It is shown that enzymes that were originally described as azoreductases, are likely to act as NADH quinone oxidoreductases. The low sequence identities observed among NAD(P)H quinone oxidoreductase and azoreductase enzymes suggests convergent evolution.

Therapeutic strategies for the management of ulcerative colitis

Induction and maintenance of remission, mucosal healing, the avoidance of surgical intervention, and decreasing the likelihood of cancer developing are the primary therapeutic goals in ulcerative colitis (UC). For the traditional therapies, 5-aminosalicylic acid (including mesalamine), corticosteroids, and thiopurines (azathioprine and mercaptopurine), there are major changes evolving in terms of formulation, patterns of use, and appreciation of long-term benefits and toxicities. The calcineurin inhibitors cyclosporin and tacrolimus, and infliximab, have recently defined, well-established roles. Preliminary supportive evidence is emerging in relation to novel antiinflammatory molecules such as curcumin, manipulation of the bacterial flora, enhancement of the mucosal barrier, and direct epithelial restoration. For patients in whom the disease is resistant to standard simple therapies, strategies are required to integrate these developing and new therapies into clinical practice. This review aims to highlight the evidence supporting new patterns of use of existing therapies and new therapies, and to devise therapeutic pathways that incorporate these new treatments. We propose how treatment might be optimized to improve the outcome in patients with mild-to-moderately active UC, chronic active UC, resistant proctitis, and fulminant UC.