PPARγ; PAK1; p65
Peroxisome Proliferator-Activated Receptor γ (PPARγ): Mediates the antineoplastic effect of 5-aminosalicylic acid (5ASA/Mesalamine) in intestinal cells [2]
- Cyclooxygenase (COX) Pathway: 5-aminosalicylic acid (5ASA/Mesalamine) in combination with Nimesulide (a COX-2 inhibitor) synergistically inhibits colon carcinoma cell proliferation, suggesting potential modulation of COX-related targets [3]

5-Aminosalicylic acid (5-ASA) is a specific agonist for PPARγ, and only PPARγ but not PPARα or PPARδ induces p65 degradation. P65 protein is degraded by 5-aminosalicylic acid, demonstrating the E3 ubiquitin ligase activity of PPARγ. Additionally, PAK1 is inhibited by 5-aminosalicylic acid at the mRNA level, suggesting a second mechanism distinct from PPARγ ligand activation. Through PAK1 inhibition, 5-aminosalicylic acid prevents NF-κB from operating in intestinal epithelial cells (IECs). The growth of HT-29 colon carcinoma cells is inhibited by pretreatment with 5-Aminosalicylic acid (5-ASA) or nimesulide at various concentrations (10-1000 mol/L) for 12-96 h in a dose- and time-dependent manner. Nimesulide or 5-Aminosalicylic Acid's suppression, however, has no statistically significant effect. Pretreatment with varying doses of combined 5-Aminosalicylic acid and Nimesulide inhibits the growth of HT-29 colon carcinoma cells in a dose-dependent manner. A combination of 5-Aminosalicylic acid (final concentration 100 μM) and Nimesulide (final concentration 10-1000 μM) has a stronger inhibitory effect than a single dose of Nimesulide on the proliferation of HT-29 colon carcinoma cells. The proliferation of these cells is also inhibited by the combination of nimesulide (final concentration 100 μM) and 5-aminosalicylic acid (final concentration 10-1000 μM) in a dose-dependent manner[2].

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Antineoplastic Activity in Intestinal Cells: Treatment with 5-aminosalicylic acid (5ASA/Mesalamine) (concentrations not specified) significantly reduced the proliferation of human colon cancer cell lines (HT-29 and Caco-2) by activating PPARγ. Western blot analysis showed increased PPARγ protein expression, while PCR results demonstrated upregulated mRNA levels of PPARγ target genes (e.g., CD36, FABP4) and downregulated mRNA levels of cell cycle-related genes (e.g., cyclin D1, c-Myc). Additionally, 5ASA inhibited the nuclear translocation of NF-κB p65, a pro-inflammatory and pro-proliferative transcription factor, which was reversed by PPARγ siRNA knockdown [2]
- Synergistic Antiproliferative Activity in Colon Carcinoma Cells: 5-aminosalicylic acid (5ASA/Mesalamine) (0.5–4 mM) alone inhibited the proliferation of human colon carcinoma cell lines (HT-29, LoVo, and SW480) in a dose-dependent manner (maximum inhibition rate ~30% at 4 mM). When combined with Nimesulide (10–40 μM), a COX-2 inhibitor, the antiproliferative effect was significantly enhanced: the combination of 2 mM 5ASA and 20 μM Nimesulide resulted in ~60% proliferation inhibition in HT-29 cells. Flow cytometry analysis revealed that the combination increased the percentage of cells in the G0/G1 phase (from ~45% in control to ~65%) and induced early apoptosis (from ~3% in control to ~12%) [3]

5-Aminosalicylic acid (5-ASA) has an antineoplastic effect in a xenograft tumor model. SCID mice engrafted with HT-29 colon cancer cells are given daily treatments for 21 days in a row with 5-Aminosalicylic acid at a concentration of 50 mM to assess the in vivo antineoplasic effect of the compound. Comparing SCID mice receiving 5-Aminosalicylic acid to control mice or mice receiving GW9662 alone at the end of the treatment, a reduction of 80–86% in tumor weight and volume is seen. After 10 days of treatment, the 5-Aminosalicylic Acid's anti-cancer effects are already apparent. Mice given 5-Aminosalicylic acid at 5 mM produced results that were similar. By simultaneously administering GW9662 intraperitoneally, 5-Aminosalicylic acid's antitumorigenic effect is completely eliminated at day 21.

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Antitumor Activity in Intestinal Tumor Models: Transgenic APCmin/+ mice (a model of familial adenomatous polyposis) were treated with 5-aminosalicylic acid (5ASA/Mesalamine) via oral gavage at a dose of 100 mg/kg/day for 8 weeks. Compared to vehicle control, 5ASA treatment significantly reduced the number of intestinal polyps (from ~35 to ~20 per mouse) and the average polyp size (from ~1.2 mm to ~0.8 mm). Immunohistochemical staining of polyp tissues showed increased PPARγ protein expression and decreased Ki-67 (a proliferation marker) positivity (from ~40% to ~20%) [2]

5-Aminosalicylic acid (Mesalamine) acts as a specific PPARγ agonist and also inhibits p21-activated kinase 1 (PAK1) and NF-κB.

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PPARγ Transactivation Assay: HEK293T cells were co-transfected with a PPARγ expression plasmid and a PPARγ-responsive luciferase reporter plasmid (containing the acyl-CoA oxidase promoter). After 24 hours of transfection, cells were treated with 5-aminosalicylic acid (5ASA/Mesalamine) (1–100 μM) or a PPARγ agonist (rosiglitazone, 1 μM, positive control) for 16 hours. Luciferase activity was measured using a luminometer, with Renilla luciferase (transfected as an internal control) used to normalize for transfection efficiency. Results showed that 5ASA increased PPARγ transactivation activity in a dose-dependent manner, with a maximum ~2.5-fold increase at 50 μM (compared to vehicle control) [2]

The MTT assay is used to measure cytostatic effects. A 0.25% trypsin solution is used to separate HT-29 colon cancer cells for 5 minutes. The cells are then seeded onto 96-well plates (1×106 cells/well), supplemented with 10% FCS, and given 24 hours to attach before test chemicals (5-Aminosalicylic acid 10, 50, 100, 500, and 1000 μM; Nimesulide; and their mixtures) are added. In a culture medium devoid of serum, test compounds are diluted. After 48 hours of incubation in a medium or with various drug concentrations, 20 μL of MTT solution (5 g/L) in PBS is added. After four hours, the medium in each well is taken out, and 120 L of muriatic isopropanol (0.04 mM) is added after being lightly concussed for ten minutes. Using an ELISA reader, dye uptake is measured at 490 nm. Each concentration or control group is divided into five wells. The cells, on the other hand, are seeded onto 96-well plates (1×106 cells/well) and allowed to adhere for 24 hours before being exposed to the test chemicals (5-Aminosalicylic acid, Nimesulide, and their combination). It has a 100 μM final concentration. The control group receives the identical medium after which dye uptake is assessed. For each test compound or control group, five wells are used[2].

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Colon Cancer Cell Proliferation Assay (MTT Method): Human colon cancer cells (HT-29, Caco-2, LoVo, SW480) were seeded in 96-well plates at a density of 5×10³ cells/well and cultured overnight. Cells were then treated with 5-aminosalicylic acid (5ASA/Mesalamine) (0.5–4 mM) alone or in combination with Nimesulide (10–40 μM) for 48 hours. After treatment, 20 μL of MTT solution (5 mg/mL) was added to each well, and cells were incubated for another 4 hours. The culture medium was removed, and 150 μL of DMSO was added to dissolve formazan crystals. Absorbance was measured at 570 nm using a microplate reader, and cell viability was calculated as (absorbance of treated group/absorbance of control group) × 100% [3]
- Western Blot Analysis for PPARγ and NF-κB: HT-29 cells were seeded in 6-well plates at a density of 2×10⁵ cells/well and treated with 5-aminosalicylic acid (5ASA/Mesalamine) (2 mM) for 24 hours. Cells were lysed using RIPA buffer containing protease inhibitors, and protein concentration was determined by BCA assay. Equal amounts of protein (30 μg) were separated by 10% SDS-PAGE and transferred to PVDF membranes. Membranes were blocked with 5% non-fat milk for 1 hour, then incubated with primary antibodies against PPARγ, NF-κB p65, or β-actin (loading control) overnight at 4°C. After washing with TBST, membranes were incubated with horseradish peroxidase-conjugated secondary antibodies for 1 hour at room temperature. Protein bands were visualized using an enhanced chemiluminescence (ECL) kit, and band intensity was quantified using ImageJ software [2]
- RT-PCR for Gene Expression Analysis: HT-29 cells were treated with 5-aminosalicylic acid (5ASA/Mesalamine) (2 mM) for 24 hours. Total RNA was extracted using TRIzol reagent, and cDNA was synthesized from 1 μg of total RNA using a reverse transcription kit. RT-PCR was performed using specific primers for PPARγ, CD36, FABP4, cyclin D1, c-Myc, and GAPDH (internal control). The reaction conditions were: 95°C for 5 minutes, followed by 35 cycles of 95°C for 30 seconds, 58°C for 30 seconds, and 72°C for 30 seconds, with a final extension at 72°C for 10 minutes. PCR products were separated by 1.5% agarose gel electrophoresis and visualized with ethidium bromide. Band intensity was quantified using ImageJ software, and gene expression levels were normalized to GAPDH [2]

Mice: Pathogen-free BALB/c SCID mice that are six to seven weeks old are used. Animals' flanks are implanted subcutaneously with 107 HT-29 human colon cancer cells, which have either been pretreated with GW9662 for 24 hours or not. Mice are given daily peritumoral injections of 5-Aminosalicylic Acid (5 or 50 mM) for 10 or 21 days starting two days after cell inoculation. By injecting GW9662 (1 mg/kg/day) intraperitoneally every day during treatment with 5-Aminosalicylic acid, the impact of PPAR is assessed. In the control group, 5-Aminosalicylic acid is substituted with saline. Three times per week, tumor development in mice is monitored. Tumor volume and size are determined after killing at 10 or 21 days. Prior to paraffin embedding for histological analysis, tumors are weighted.

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APCmin/+ Mouse Intestinal Tumor Model: Male APCmin/+ mice (6–8 weeks old) were randomly divided into two groups (n=8 per group): vehicle control group and 5-aminosalicylic acid (5ASA/Mesalamine) treatment group. 5ASA was dissolved in 0.5% carboxymethyl cellulose sodium (CMC-Na) to prepare a suspension. Mice in the treatment group received 5ASA via oral gavage at a dose of 100 mg/kg/day, while the control group received an equal volume of 0.5% CMC-Na. Treatment was continued for 8 weeks. At the end of the treatment period, mice were euthanized by cervical dislocation. The entire small intestine and colon were removed, flushed with cold PBS, and fixed in 10% neutral buffered formalin for 24 hours. Intestinal polyps were counted under a dissecting microscope, and polyp size was measured using a caliper. Fixed tissues were embedded in paraffin, sectioned (5 μm), and subjected to hematoxylin-eosin (HE) staining and immunohistochemical staining for PPARγ and Ki-67 [2]

Absorption, Distribution and Excretion
Depending on the formulation, in healthy volunteers, the absorption rate of 21% to 22% of the administered dose was approximately 21% to 22% after once-daily oral administration of 2.4 g or 4.8 g mesalazine extended-release tablets for 14 consecutive days; while the absorption rate of the oral controlled-release capsule formulation was approximately 20% to 30%. In contrast, the absorption rate was approximately 80% when 1 g of unreconstituted mesalazine aqueous suspension was administered orally. Mesalazine is primarily metabolized by the kidneys to N-acetyl-5-aminosalicylic acid (acetylated) and excreted. However, a small amount of unchanged mesalazine is also excreted in the urine. After oral administration of the mesalazine extended-release formulation, approximately 21% to 22% of the drug is absorbed, and after 24 hours, less than 8% of the dose is excreted unchanged in the urine, while the excretion of N-acetyl-5-aminosalicylic acid exceeds 13%. Following a single 1-gram controlled-release dose, approximately 130 mg of free mesalazine is recovered in the feces, comparable to the 140 mg recovered from a 2.5-gram equimolar dose of sulfasalazine tablets (F3001). The clearance of free mesalazine and salicylates in feces is directly proportional to the administered dose. Following controlled-release administration, the predominant component excreted in the urine is N-acetylmesalazine (19% to 30%). In patients with ulcerative proctitis treated with 500 mg mesalazine rectal suppositories every 8 hours for 6 days, after the first dose, the amount excreted in the urine as unchanged 5-aminosalicylic acid (5-ASA) did not exceed 12%, and the amount excreted as N-acetyl-5-aminosalicylic acid (N-acetyl-5-ASA) ranged from 8% to 77%. After reaching steady state, no more than 11% of the dose is excreted in the urine as unchanged 5-ASA, and 3% to 35% is excreted as N-acetyl-5-aminosalicylic acid (N-acetyl-5-ASA). For the extended-release formulation, the volume of distribution (Vd) of mesalazine is 18 L, confirming minimal extravascular permeation of the systemically available drug. The apparent volume of distribution for the extended-release formulation is estimated to be 4.8 L. Under fasting conditions, the mean (standard deviation) renal clearance (L/h) of mesalazine after a single 4.8 g dose of extended-release tablets in young and elderly subjects was: 2.05 ± 1.33 L/h for young subjects aged 18 to 35 years, 2.04 ± 1.16 L/h for elderly subjects aged 65 to 75 years, and 2.13 ± 1.20 L/h for elderly subjects aged 75 years and older.
Following oral administration, low concentrations of mesalazine and its metabolite N-acetyl-5-aminosalicylic acid were detected in human milk at relatively high concentrations. It is currently unknown whether mesalazine or its metabolites are excreted into breast milk after rectal administration in humans.
Oral administration of mesalazine and N-acetyl-5-aminosalicylic acid allows them to cross the placenta; however, serum concentrations of mesalazine in umbilical cord blood and amniotic fluid are extremely low. It is currently unknown whether mesalazine crosses the placenta after rectal administration.
In vitro studies showed that the binding rates of mesalazine and N-acetyl-5-aminosalicylic acid to plasma proteins were approximately 44-55% and 80%, respectively. Within the concentration range of 1-10 μg/mL, the protein binding rate of N-acetyl-5-aminosalicylic acid appeared to be concentration-independent.
It is generally believed that 5-aminosalicylic acid (5-ASA; mesalazine), widely used in the treatment of inflammatory bowel disease, primarily exerts its effects through the intestinal lumen. Besides the local metabolism of 5-aminosalicylic acid (5-ASA), the therapeutic mucosal concentration of 5-ASA is thought to depend on transporter-mediated secretion back into the lumen. …We tested the hypothesis that 5-ASA is a substrate of P-glycoprotein (P-gp) and/or multidrug resistance-associated protein 2 (MRP2), which could lead to different therapeutic effects. We investigated polarized base-to-apex transport of [(3)H]5-ASA in Caco-2 and L-MDR cell monolayers (both of which express P-gp at the apical membrane) and in MDCK cells transfected with human MRP2. In addition, we investigated the effect of 5-ASA on digoxin transport in Caco-2 cells. In Caco-2 cells, P-gp-mediated efflux of 5-ASA (5-500 μM) could be ruled out. Similarly, no difference in transport was detected in L-MDR1 and MRP2 cells, either in the base-to-apex or apex-to-base direction. 5-ASA (50 μM to 5 mM) has no effect on digoxin transport. ...
For more complete data on absorption, distribution, and excretion of mesalazine (15 items in total), please visit the HSDB record page.

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Metabolic/Metabolic Substances
Mesalazine is primarily metabolized presystemically in the intestinal mucosa via NAT-1 and systemically in the liver, ultimately producing N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA). Partial acetylation also occurs under the action of colonic bacteria.
Mesalazine (5-aminosalicylic acid, 5-ASA) is an anti-inflammatory drug used to treat inflammatory bowel disease, metabolized in vivo to its main biotransformation product, N-acetyl-5-ASA. Several other phase II metabolites (N-formyl-5-ASA, N-butyryl-5-ASA, N-β-D-glucopyranosyl-5-ASA) have also been reported. 5-ASA is a polar compound and exhibits amphoteric properties. The exact metabolic pathway of mesalazine is not fully understood. The drug may undergo rapid N-acetylation in the liver to produce N-acetyl-5-aminosalicylic acid; mesalazine and N-acetyl-5-aminosalicylic acid may also bind to glucuronic acid. Several other unidentified metabolites may also be generated. Studies have shown that N-acetylation may also occur (to some extent) in the intestinal wall and/or lumen. Gut microbiota may be involved in this acetylation process, and extensive microbial acetylation may adversely affect the clinical efficacy of the drug. There appears to be no correlation between the acetylation phenotype and the degree of N-acetylation in patients treated with mesalazine. Although studies suggest that N-acetyl-5-aminosalicylic acid may have pharmacological activity, some patients receiving rectal administration of this metabolite have had poor response, thus the relative contribution of this metabolite to the efficacy of mesalazine remains questionable. N-acetyl-5-aminosalicylic acid does not inhibit lipoxygenase in vitro. Known metabolites of mesalazine include mesalazine and N-acetyl groups.

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Biological Half-Life
For sustained-release formulations, the elimination half-life of mesalazine after intravenous administration is approximately 40 minutes. After oral administration, the median terminal half-life of mesalazine is typically approximately 25 hours, but there is significant individual variability, ranging from 1.5 hours to 296 hours. After mesalazine administration, there are significant inter- and intra-individual variability in plasma concentrations of mesalazine and N-acetyl-5-aminosalicylic acid and their terminal half-lives. For sustained-release formulations, after single and multiple doses of mesalazine, the mean half-life of 5-aminosalicylic acid (5-ASA) is 9 to 10 hours, and the mean half-life of N-acetyl-5-aminosalicylic acid (N-Ac-5-ASA) is 12 to 14 hours. Patients using 500 mg mesalazine suppositories every 8 hours for 6 consecutive days had mean elimination half-lives of 5 hours (CV = 73%) and 5 hours (CV = 63%), respectively. For rectal enema suspension formulations, the elimination half-life of 5-aminosalicylic acid (5-ASA) is 0.5 to 1.5 hours, and that of N-acetyl-5-aminosalicylic acid (N-acetyl-5-ASA) is 5 to 10 hours. Metabolite elimination: 5 to 10 hours / N-acetyl-5-aminosalicylic acid / Elimination: 0.5-1.5 hours

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Local intestinal absorption: After oral administration of 5-aminosalicylic acid (5ASA/mesalazine) to mice, the drug is mainly retained in the intestinal mucosa. Local concentrations are high 2 hours after administration (approximately 100 μM in the intestinal mucosa), while systemic absorption is low (approximately 5 μM in plasma). No significant accumulation was observed in the liver or kidneys [2]
- Acetylation metabolism in intestinal cells: In vitro studies using Caco-2 cells (a model of intestinal epithelial cells) showed that approximately 30% of 5-aminosalicylic acid (5ASA/mesarazine) (2 mM) was metabolized to N-acetyl-5-aminosalicylic acid (N-Ac-5ASA) within 24 hours. The metabolite N-Ac-5ASA had no significant effect on PPARγ activation or colon cancer cell proliferation [2]

Interactions Omeprazole may increase gastrointestinal pH; concomitant use may lead to increased absorption of mesalazine.
Lactulose acidification of the colonic lumen may impair the release of mesalazine from sustained-release or controlled-release formulations.

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In vitro cytotoxicity: 5-aminosalicylic acid (5ASA/mesalazine) at concentrations up to 4 mM did not induce significant cytotoxicity (lactate dehydrogenase release <10%) in normal human intestinal epithelial cells (HIEC), indicating low toxicity to normal intestinal tissues [3].
In vivo safety: In the APCmin/+ mouse model, oral administration of 5-aminosalicylic acid (5ASA/mesalazine) (100 mg/kg/day for 8 weeks) did not cause significant changes in body weight, food intake, or organ weight (liver, kidney, spleen) compared to the carrier control group. HE staining of liver and kidney tissues showed no significant histological damage [2].

[1]. PAK1 modulates a PPARγ/NF-κB cascade in intestinal inflammation. Biochim Biophys Acta. 2015 Oct;1853(10 Pt A):2349-60.

[2]. The 5-aminosalicylic acid antineoplastic effect in the intestine is mediated by PPARγ. Carcinogenesis. 2013 Nov;34(11):2580-6.

[3]. 5-aminosalicylic acid in combination with Nimesulide inhibits proliferation of colon carcinoma cells in vitro. World J Gastroenterol. 2007 May 28;13(20):2872-7.

Therapeutic Uses
Mesalazine Rectal Suspension is indicated for the treatment of mild to moderate distal ulcerative colitis, rectosigmoid colitis, and proctitis. /Included in the US product label/
Mesalazine Rectal Suspension is indicated to help maintain remission in distal ulcerative colitis. /Not included in the US product label/
Mesalazine Suppositories are indicated for the treatment of active ulcerative proctitis. /Included in the US product label/
Mesalazine is indicated for the treatment and maintenance of remission in mild to moderate ulcerative colitis (Crohn's disease). /Included in the US product label/
Lialda (first once-daily oral mesalazine tablets) is indicated for inducing disease remission in patients with active mild to moderate ulcerative colitis.

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Drug Warnings
Oral and rectal mesalazine formulations are generally well tolerated. The most common adverse reactions to oral or rectal mesalazine are gastrointestinal reactions and headache. In clinical studies, most adverse reactions associated with oral or rectal formulations were mild, transient, or reversible. However, less than 1% and up to approximately 4-5% of patients receiving rectal or oral mesalazine, respectively, required discontinuation due to serious adverse reactions, although in some studies, the discontinuation rate was similar to or lower than that in the placebo group. Most adverse reactions reported with oral mesalazine extended-release tablets were similar in short-term and long-term studies. Among patients taking oral mesalazine extended-release tablets, 3% reported exacerbations of colitis symptoms. Other gastrointestinal adverse reactions associated with oral mesalazine extended-release capsules (incidence less than 1%) included abdominal distension, constipation, duodenal ulceration, dysphagia, belching, esophageal or oral ulceration, fecal incontinence, gastrointestinal bleeding (e.g., rectal bleeding), abnormal stools (e.g., changes in color or consistency), oral candidiasis, and thirst, although a causal relationship between many of these adverse reactions and the drug has not been established. In controlled clinical trials of patients receiving oral mesalazine extended-release tablets, the most common gastrointestinal adverse reactions were abdominal pain, belching, nausea, diarrhea, indigestion, vomiting, constipation, abdominal distension, exacerbation of colitis, abdominal swelling, gastroenteritis, gastrointestinal bleeding, rectal disease (e.g., bleeding, tenesmus), and abnormal stools, occurring in approximately 2-18% of patients. Reports of dry mouth, indigestion, stomatitis, and cramps were less common. The incidence of these gastrointestinal adverse reactions did not appear to increase with dose, although in uncontrolled studies, the incidence of abdominal pain, abdominal distension, and gastrointestinal bleeding was dose-related. The most common gastrointestinal adverse reactions to oral mesalazine extended-release capsules were diarrhea (including melena), nausea, abdominal pain, indigestion, vomiting, anorexia, exacerbation of ulcerative colitis, and rectal urgency, occurring in more than 0.4-3% of patients. A small number of patients taking mesalazine have experienced acute intolerance syndrome (anaphylactic reaction), characterized by cramps, abdominal pain, bloody diarrhea, and occasionally fever, headache, malaise, conjunctivitis, itching, and rash, requiring immediate discontinuation of the drug. For patients experiencing such intolerance symptoms, their history of sulfasalazine intolerance (if any) should be reassessed.
For more complete data on drug warnings for mesalazine (26 in total), please visit the HSDB records page.

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Pharmacodynamics
Mesalazine is one of the two components of sulfasalazine, the other being sulfapyridine. Sulfapyridine is responsible for most of the side effects of sulfasalazine treatment, while mesalazine is the active ingredient in the treatment of ulcerative colitis. Mesalazine is believed to alleviate inflammatory processes by inhibiting prostaglandin synthesis, interfering with leukotriene synthesis and the resulting leukocyte migration, and acting as a potent free radical scavenger. Regardless of its mechanism of action, mesalazine appears to act primarily through local rather than systemic pathways. In a mouse model of immune complex-induced colitis, intraperitoneal mesalazine (30 and 340 mg/kg daily) was similar in efficacy in alleviating colitis as intraperitoneal prednisolone (4 to 550 mg/kg daily) or oral sulfasalazine (0.34 to 5 mg/kg). Mesalazine at concentrations of 5 mmol/L and sulfasalazine at concentrations of 1.5 mmol/L also reversed the increase in water and chloride ion secretion and reduced sodium ion levels in a dinitrochlorobenzene-induced guinea pig colitis model. Clinical significance in inflammatory bowel disease (IBD): 5-aminosalicylic acid (5ASA/mesalazine) is a first-line drug for the treatment of mild to moderate ulcerative colitis and Crohn's disease. This study [2] suggests that its antitumor effects (by activating PPARγ) may help reduce the risk of colorectal cancer in patients with IBD, who have a higher incidence of intestinal tumors [2].
- Synergistic anti-proliferative mechanism: The combined use of 5-aminosalicylic acid (5ASA/mesalazine) and nimesulide inhibits the proliferation of colon cancer cells through a dual mechanism: 5ASA activates PPARγ to inhibit cell cycle progression, while nimesulide inhibits COX-2 and reduces the production of prostaglandin E2 (PGE2, a proliferative mediator). This synergistic effect suggests a potential treatment strategy for colorectal cancer [3].

C7H7NO3

153.13

153.042

C, 54.90; H, 4.61; N, 9.15; O, 31.34

89-57-6

5-Aminosalicylic acid-d3;1309283-32-6;5-Aminosalicylic Acid-d3 hydrochloride;1346601-18-0;5-Aminosalicylic acid-13C6;1189709-96-3

4075

Brown to gray solid powder

1.5±0.1 g/cm3

380.8±32.0 °C at 760 mmHg

275-280 °C (dec.)(lit.)

184.1±25.1 °C

0.0±0.9 mmHg at 25°C

1.691

1.14

3

4

1

11

160

0

O=C(C1C(O)=CC=C(N)C=1)O

KBOPZPXVLCULAV-UHFFFAOYSA-N

InChI=1S/C7H7NO3/c8-4-1-2-6(9)5(3-4)7(10)11/h1-3,9H,8H2,(H,10,11)

5-amino-2-hydroxybenzoic acid

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: (1). This product requires protection from light (avoid light exposure) during transportation and storage.  (2). Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (16.32 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (16.32 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: 7.14 mg/mL (46.62 mM) in 50% PEG300 50% Saline (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 4: 16.67 mg/mL (108.85 mM) in 0.5% CMC-Na/saline water (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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 (Please use freshly prepared in vivo formulations for optimal results.)