Balsalazide is a new 5-aminosalicylic acid (5-ASA) prodrug [2]. At endpoint, protein production of MIP-1β, MCP-1, IL-6, and IL-10 in colon tissue decreased with plasma concentrations of the cytokines. Additionally, the drug treatment group showed lower expression of p-STAT3 compared with the CAC group, and BCL2 was significantly reduced and BAX was significantly increased.
In Vivo: In a murine azoxymethane (AOM)/dextran sodium sulfate (DSS) model of colitis‑associated carcinogenesis, C57B/L6J mice were administered Balsalazide (300 mg/kg) alone or with VSL#3 for 2 weeks before AOM injection (10 mg/kg i.p.) and during two cycles of 2% DSS (7 days each). At endpoint (day 44), Balsalazide significantly reduced the total number of tumors compared to the CAC group (P<0.05), especially tumors ≥2 mm. It decreased F4/80‑positive macrophage infiltration in colitic tissues and tumor stroma (P<0.05 and P<0.01, respectively). Protein and mRNA levels of MIP‑1β, MCP‑1, IL‑6, and IL‑10 in colon tissues were reduced, and p‑STAT3 expression was suppressed. BCL2 decreased and BAX increased in the Balsalazide+VSL#3 group [1].
In a double‑blind, multicentre, randomised trial (26‑week) in 133 UC patients in remission, Balsalazide (1.5 g twice daily, n=49; 3.0 g twice daily, n=40) was compared with mesalazine (0.5 g three times daily, n=44). High‑dose Balsalazide resulted in a significantly higher clinical remission rate (77.5%) than low‑dose (43.8%) and mesalazine (56.8%) (p=0.006). Time to relapse was 161 days for high‑dose, 131 days for low‑dose (p=0.003), and 144 days for mesalazine (NS). Final endoscopic score significantly favoured high‑dose over low‑dose (p=0.005). No significant differences in histological scores were observed [2].

Animal Protocol: Male C57B/L6J mice (4‑weeks‑old) were randomly divided into four groups (n≥10 per group): CAC group (no drug), BSZ group (300 mg/kg Balsalazide), VSL#3 group (1.3 × 10⁶ bacteria/day), and BSZ+VSL#3 group. Drugs were administered orally (dietary) starting 2 weeks before AOM injection and continued for 9 weeks until sacrifice. A single intraperitoneal injection of AOM (10 mg/kg) was given, followed one week later by 2% DSS in drinking water for 7 days (1st cycle). After a 2‑week rest, a second 2% DSS cycle for 7 days was given. Mice were sacrificed at day 44. Disease activity index (DAI) was scored. Colon tissues were collected for immunohistochemistry (F4/80), immunoblotting (p‑STAT3, BCL2, BAX, etc.), RT‑PCR (MCP‑1, IL‑10, etc.), and tumor counting [1].
Human clinical trial: Patients with ulcerative colitis in remission (CAI<6 and EI<4) received oral Balsalazide capsules (1.5 g twice daily or 3.0 g twice daily) or mesalazine (Eudragit‑coated, 0.5 g three times daily) for 26 weeks. Clinical visits at weeks 4, 8, 17, and endpoint. Compliance monitored by returned drug count. Primary endpoint: remission (CAI<6 and EI<4) at study completion. Secondary endpoints: time to relapse, endoscopic score, histological score, urinary excretion of 5‑ASA and N‑Ac‑5‑ASA, and safety [2].

ADME/Pharmacokinetics: In human UC patients, 24‑hour urinary excretion of 5‑ASA and its metabolite N‑acetyl‑5‑ASA (N‑Ac‑5‑ASA) was measured after chronic treatment (26 weeks). For Balsalazide (both doses combined, n=89), mean urinary excretion as % of 5‑ASA dose was: 5‑ASA 0.89% (95% CI 0.50‑1.58), N‑Ac‑5‑ASA 9.5% (6.60‑13.70), total recovery 11.5% (8.0‑16.7). For mesalazine (n=44), values were: 5‑ASA 1.81% (0.83‑3.92), N‑Ac‑5‑ASA 14.9% (9.10‑24.30), recovery 18.7% (11.4‑30.6). Differences were not statistically significant (p=0.147 for each comparison). Balsalazide is a prodrug that releases 5‑ASA in the colon via bacterial azo reduction [2].

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
While there is currently no information on whether balsalazine is excreted into breast milk, it is metabolized in breast milk to the active drug mesalazine. A small number of infants have been reported to experience diarrhea after taking mesalazine, but the incidence is low. Most experts and professional guidelines consider mesalazine derivatives safe for breastfeeding women. ◉ Effects on Breastfed Infants
Mesalazine, the active metabolite of balsalazine, may have been the cause of diarrhea in a 6-week-old infant who experienced four recurrences of diarrhea after the mother took balsalazine four times during breastfeeding.
In a prospective telephone follow-up study, eight breastfeeding mothers reported taking mesalazine (dosage and route of administration not specified). One mother reported diarrhea in her infant. No other adverse reactions were reported in the infants by the mothers.
A case-control study compared infants born to mothers receiving mesalazine (n = 117; mean dose, 2065 mg daily), olsalazine (n = 2), or sulfasalazine (n = 2) with infants born to a mother-matched control group (n = 121). Control group mothers did not receive any treatment known to be harmful to breastfed infants. The mean duration of breastfeeding exposure to mesalazine was 5.3 months (range: 3 days to 24 months). Infants were breastfed for approximately 7.4 months on average and followed up at a mean of approximately 22 months of age. There were no differences in the frequency or characteristics of maternally reported adverse events between the exposed and control groups.
◉ Effects on breastfeeding and breast milk
As of the revision date, no relevant published information was found.

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In Vivo (murine): No specific toxicity data reported; drug was well tolerated with no mention of adverse events in the animal study [1].
In human trial: Discontinuation due to adverse events occurred in 3/49 (6.1%) patients on Balsalazide 1.5 g bid, 2/40 (5.0%) on 3.0 g bid, and 4/44 (9.0%) on mesalazine. Adverse events per 1000 treatment days were similar across groups. Specific adverse events in Balsalazide groups included headache, hypertension, malaise, dizziness, abdominal pain, pruritus, skin rash (low dose), and pancreatitis, gingivitis, alopecia, nail disorders (high dose). No clinically important new drug safety findings were identified. Urine protein analysis (SDS‑PAGE) and glutathione‑S‑transferase‑π measurement showed no evidence of tubular damage [2].

[1]. Suppression of colitis-associated carcinogenesis through modulation of IL-6/STAT3 pathway by balsalazide and VSL#3. J Gastroenterol Hepatol. 2016 Aug;31(8):1453-61.

[2]. Low dose balsalazide (1.5 g twice daily) and mesalazine (0.5 g three times daily) maintained remission of ulcerative colitis but high dose balsalazide (3.0 g twice daily) was superior in preventing relapses. Gut, 2001. 49(6): p. 783-789.

Balsalazine is a monohydroxybenzoic acid composed of 5-aminosalicylic acid (mesalazine) linked to 4-aminobenzoyl-β-alanine via an azo bond. It is used as a prodrug, nonsteroidal anti-inflammatory drug, anti-ulcer agent, and gastrointestinal medication. It is the conjugate acid of balsalazine (2-). Balsalazine is an aminosalicylic acid salt. See also: Balsalazine (note moved to); Balsalazine disodium (note moved to).

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Additional Info: Balsalazide is a 5‑ASA prodrug that is pharmacologically inert until cleaved by colonic bacteria. The carrier molecule 4‑aminobenzoyl‑β‑alanine is devoid of systemic effects. In murine CAC model, Balsalazide suppressed IL‑6/STAT3 pathway, reduced macrophage infiltration, and decreased tumor formation, suggesting chemopreventive potential. In humans, high‑dose Balsalazide (3.0 g twice daily) was superior to low dose and to mesalazine in maintaining remission of ulcerative colitis, with a favourable safety profile [1][2].

357.096

80573-04-2

Balsalazide sodium hydrate;150399-21-6;Balsalazide-d4;2714315-25-8

54585

Yellow to orange solid powder

1.4±0.1 g/cm3

254-255ºC

1.650

1

4

8

7

26

545

0

C(C1C(O)=CC=C(/N=N/C2C=CC(C(=O)NCCC(=O)O)=CC=2)C=1)(=O)O

IPOKCKJONYRRHP-UHFFFAOYSA-N

InChI=1S/C17H15N3O6/c21-14-6-5-12(9-13(14)17(25)26)20-19-11-3-1-10(2-4-11)16(24)18-8-7-15(22)23/h1-6,9,21H,7-8H2,(H,18,24)(H,22,23)(H,25,26)

5-[[4-(2-carboxyethylcarbamoyl)phenyl]diazenyl]-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

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

DMSO : ~100 mg/mL (~279.86 mM)
1M NaOH : 50 mg/mL (~139.93 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.00 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 (7.00 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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 (Please use freshly prepared in vivo formulations for optimal results.)