Mesalazine, also known as 5-aminosalicylic acid (5-ASA), is an anti-inflammatory drug primarily used in the treatment of chronic inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease. It is a compound with anti-inflammatory properties that works directly on the gastrointestinal tract, reducing inflammation and alleviating symptoms associated with these conditions.
Chemical Composition and Structure
Mesalazine is a derivative of salicylic acid, and its chemical structure consists of a benzene ring attached to an amine group (-NH₂) and a carboxyl group (-COOH).
Chemical formula: C7H7NO3
Structure: Mesalazine consists of a benzene ring with an amine group (-NH₂) in position 5 and a carboxyl group (-COOH) in position 1, distinguishing it from other salicylates.
Physical Properties
Appearance: Mesalazine is a white or slightly yellow crystalline powder.
Solubility: It is soluble in water, but its solubility may vary depending on the pharmaceutical formulation.
Odor: Mesalazine has a neutral odor, which does not interfere with its use in pharmaceutical formulations.
Benefits and Functions
Anti-inflammatory: Mesalazine is used to reduce inflammation in the gastrointestinal tract, especially in the treatment of ulcerative colitis and Crohn's disease. It acts locally in the intestine, reducing inflammation without significant systemic effects.
Treatment of inflammatory bowel diseases: Mesalazine is the treatment of choice for maintaining remission and reducing flare-ups of ulcerative colitis. It is often administered orally or rectally, depending on the location of the inflammation.
Prevention of relapses: It is also used to prevent relapses in patients with chronic inflammatory bowel diseases.
Applications
Pharmaceutical
Treatment of ulcerative colitis and Crohn's disease: Mesalazine is commonly prescribed as a medication for the treatment and management of ulcerative colitis and Crohn's disease, as it helps reduce inflammation and prevent recurring symptoms.
Oral and rectal preparations: It is available in various pharmaceutical forms, such as tablets, modified-release capsules, liquid suspensions, and rectal suppositories, for treating localized inflammation in the colon.
Combination with other therapies: Mesalazine is sometimes used in combination with other therapies to enhance the effectiveness of treatment in inflammatory bowel diseases.
Cosmetics
Skin treatments: Although not a primary function, some cosmetic formulations for sensitive or inflamed skin may contain compounds similar to or derived from mesalazine, though its main use is in gastrointestinal treatments.
Environmental and Safety Considerations
Safety: Mesalazine is generally well tolerated but may cause side effects such as headaches, nausea, diarrhea, or gastrointestinal disturbances. In rare cases, it may cause allergic reactions or kidney damage.
Precautions: The drug should be used cautiously in individuals with kidney or liver problems. It is important that it is prescribed and monitored by a healthcare professional to ensure effectiveness and minimize the risk of side effects.
Biodegradability: As a pharmaceutical product, mesalazine is not intended for direct environmental contact but is eliminated through metabolism and excretion in the body.
Molecular Formula C7H7NO3
Molecular Weight 153.14 g/mol
CAS 89-57-6
UNII 4Q81I59GXC
EC Number 201-919-1
Synonyms:
Mesalamine
Mesalazine
5-Aminosalicylic acid
References__________________________________________________________________________
Picchio M, Elisei W, Tursi A. Mesalazine to treat symptomatic uncomplicated diverticular disease and to prevent acute diverticulitis occurrence. A systematic review with meta-analysis of randomized, placebo-controlled trials. J Gastrointestin Liver Dis. 2018 Sep;27(3):291-297. doi: 10.15403/jgld.2014.1121.273.pic.
Abstract. Background and aims: Symptomatic Uncomplicated Diverticular disease (SUDD) affects about 25% of patients harboring colonic diverticula. We assessed the effectiveness of mesalazine in improving symptoms (namely abdominal pain, primary outcome) and in preventing diverticulitis occurrence (secondary outcome) in patients with SUDD. Methods: Pertinent studies were selected from the Medline and the Cochrane Central Register of Controlled Trials. Only randomized clinical trials (RCTs) (irrespective of language, blinding, or publication status), which compared mesalazine, irrespective of the dosage assumption, with placebo in SUDD were evaluated. Results: Four RCTs enrolled 379 patients, 197 treated with mesalazine and 182 with placebo. Two studies provided data on symptom relief according to definition: it was achieved in 97/121 (80%) patients in the mesalazine group and in 81/129 (62.7%) patients in the placebo group (OR 0.43; 95% CI 0.24-0.75; p=0.003 in favour of the mesalazine group). Two studies provided information regarding occurrence of diverticulitis during follow-up. It occurred in 23/119 (19.3%) patients in the mesalazine group and in 34/102 (33.3%) patients in the placebo group (OR 0.35; 95% CI 0.17-0.70; p=0.003 in favour of the mesalazine group). Conclusions: Treatment with mesalazine seems to be effective in achieving symptom relief and in the primary prevention of diverticulitis in patients with SUDD.
Gautam P, Akhter MH, Anand A, Rab SO, Jaremko M, Emwas AH. Mesalamine loaded ethyl cellulose nanoparticles: optimization andin vivoevaluation of antioxidant potential in ulcerative colitis. Biomed Mater. 2024 Nov 22;20(1). doi: 10.1088/1748-605X/ad920e.
Abstract. This study aimed to optimize mesalamine (MES)-nanoparticles (NPs) using Box Behnken Design and investigate itsin vivoantioxidant potential in colon drug targeting. The formulation was prepared using oil/water (O/W) emulsion solvent evaporation technique for time dependent colonic delivery. The optimal formulation with the following parameters composition was selected: polymer concentration (% w/w) (A) = 0.63, surfactant concentration (% w/w) (B) = 0.71, sonication duration (min) (C) = 6. The outcomes showed that ethyl cellulose (EC) NP containing MES has particles size of 142 ± 2.8 nm, zeta potential (ZP) of -24.8 ± 2.3 mV, % EE of 87.9 ± 1.6%, and PDI of 0.226 ± 0.15. Scanning electron microscopy revealed NPs has a uniform and spherical shape. Thein-vitrorelease data disclosed that the EC NPs containing MES showed bursts release of 52% ± 1.6% in simulated stomach media within 2 h, followed by a steady release of 93% ± 2.9% in simulated intestinal fluid that lasted for 48 h. The MES release from NP best match with the Korsmeyer-Peppas model (R2= 0.962) and it followed Fickian diffusion case I release mechanism. The formulation stability over six-months at 25 °C ± 2 °C with 65% ± 5% relative humidity, and 40 °C ± 2 °C with 75% ± 5% relative humidity showed no significant changes in colour, EE, particle sizes and ZP. As perin vivoresults, MES-NP effectively increased glutathione, SOD level and reduces the LPO level as compared to other treatment groups. The findings hold promise that the developed formulation can suitably give in ulcerative colitis.
Słoka J, Madej M, Strzalka-Mrozik B. Molecular Mechanisms of the Antitumor Effects of Mesalazine and Its Preventive Potential in Colorectal Cancer. Molecules. 2023 Jun 29;28(13):5081. doi: 10.3390/molecules28135081.
Abstract. Chemoprevention is one of the ways to fight colorectal cancer, which is a huge challenge in oncology. Numerous pieces of evidence indicate that chronic inflammation in the course of Crohn's disease or ulcerative colitis (UC) is a significant cancer risk factor. Epidemiologic studies suggest that long-term use of non-steroidal anti-inflammatory drugs (NSAIDs), including mesalazine, has beneficial effects on colitis-associated colorectal cancer. Mesalazine is a first-line therapy for UC and is also widely used for maintaining remission in UC. Data showed that mesalazine has antiproliferative properties associated with cyclooxygenase (COX) inhibition but can also act through COX-independent pathways. This review summarizes knowledge about mesalazine's molecular mechanisms of action and chemopreventive effect by which it could interfere with colorectal cancer cell proliferation and survival.
Mesalamine Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006–. Mesalamine. 2024 Sep 15.
Abstract. Mesalamine is poorly excreted into breastmilk. However, rather high levels of the mesalamine metabolite N-acetyl-5-ASA appear in breastmilk and its effects on breastfed infants are unknown. A few cases of diarrhea have been reported in infants exposed to mesalamine, although the rate is not high. Most experts consider mesalamine derivatives to be safe during breastfeeding.[1-6] If mesalamine is required by the mother, it is not a reason to discontinue breastfeeding, but carefully observe breastfed infants for diarrhea during maternal use of mesalamine.
Park B, Han G, Jin DY, Gil KC, Shin D, Lee J, Park JY, Jang H, Park D, Lee S, Kim K, Yang Y, Kim Y, Kim JS, Kim SH, Shim MK. Mucoadhesive Mesalamine Prodrug Nanoassemblies to Target Intestinal Macrophages for the Treatment of Inflammatory Bowel Disease. ACS Nano. 2024 Jun 25;18(25):16297-16311. doi: 10.1021/acsnano.4c05544.
Abstract. While mesalamine, a 5-aminosalicylic acid (5-ASA), is pivotal in the management of inflammatory bowel disease (IBD) through both step-up and top-down approaches in clinical settings, its widespread utilization is limited by low bioavailability at the desired site of action due to rapid and extensive absorption in the upper gastrointestinal (GI) tract. Addressing mesalamine's pharmacokinetic challenges, here, we introduce nanoassemblies composed exclusively of a mesalamine prodrug that pairs 5-ASA with a mucoadhesive and cathepsin B-cleavable peptide. In an IBD model, orally administered nanoassemblies demonstrate enhanced accumulation and sustained retention in the GI tract due to their mucoadhesive properties and the epithelial enhanced permeability and retention (eEPR) effect. This retention enables the efficient uptake by intestinal pro-inflammatory macrophages expressing high cathepsin B, triggering a burst release of the 5-ASA. This cascade fosters the polarization toward an M2 macrophage phenotype, diminishes inflammatory responses, and simultaneously facilitates the delivery of active agents to adjacent epithelial cells. Therefore, the nanoassemblies show outstanding therapeutic efficacy in inhibiting local inflammation and contribute to suppressing systemic inflammation by restoring damaged intestinal barriers. Collectively, this study highlights the promising role of the prodrug nanoassemblies in enhancing targeted drug delivery, potentially broadening the use of mesalamine in managing IBD.
King-Nakaoka EA, Yu LX. Mesalamine as Treatment of Neovaginal Ileitis: Case Report and Review of Literature. J Pediatr Adolesc Gynecol. 2025 Apr;38(2):210-212. doi: 10.1016/j.jpag.2024.12.002. Epub 2024 Dec 13. PMID: 39674397.
Kim H, Kim YZ, Kim SY, Choe YH, Kim MJ. Comparison of Effects on 6-Thioguanine Nucleotides According to Mesalazine Formulation in Pediatric Patients with Ulcerative Colitis. Clin Ther. 2025 Mar;47(3):196-203. doi: 10.1016/j.clinthera.2024.12.007. Epub 2025 Jan 2. PMID: 39753503.
Szigeti R, Kellermayer R. Immunotherapy withdrawal by step-down to mesalamine in pediatric patients with ulcerative colitis. JPGN Rep. 2024 Feb 5;5(2):97-100. doi: 10.1002/jpr3.12048. PMID: 38756120; PMCID: PMC11093912.
Mesalazine 
