CA IX/carbonic anhydrase (IC50 = 30 nM)

Acetazolamide likewise suppresses hCA II with an IC50 of 130 nM [1]. Acetazolamide (Ace) is a heteroaryl starch amide that is tiny and has a high affinity for several biocyclic enzymes. It can be utilized as a dye for biocyclic amylase (CA). The Hep Vitality - 2 cells was dramatically reduced when low-concentration sodium acetazolamide (AceL, 10 nM) was mixed with high-concentration sodium acetazolamide (AceH, 50 nM), cisplatin (Cis; 1 μg/mL), and Cis in comparison to loading[2]. When compared to tomorrow, the Acetazolamide/Cis combination treatment significantly increased P53 expression levels, as AceL+Cis and AceH+Cis treatments also resulted in a significant increase in P53 expression levels. Additionally, the Ace/Cis combined treatment significantly reduced the expression of bcl-2/bax and increased the expression of caspase-3 protein. Ace and Cis together can efficiently increase Hep-2 cells. AceL, AceH, Cis, and AceL+Cis therapy dramatically lowered bcl-2 when compared with monitoring [2]. When Ace and Cis are used together, AQP1 mRNA expression in Hep-2 cells can be greatly decreased. Both AceH and AceL+Cis treatments decreased the expression of aquaporin 1 (AQP1) mRNA in Hep-2 cells as compared to the laboratory [2].

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Acetazolamide (AZ) , MS-275 and AZ + MS-275 treatments inhibit growth of NB SH-SY5Y cells. AZ, MS-275 and AZ + MS-275 treatments reduced migration capacity in NB SH-SY5Y cells. Results: We evaluated the antitumor potential of the HDAC inhibitor (HDACi), pyridylmethyl-N-{4-[(2-aminophenyl)-carbamoyl]-benzyl}-carbamate (MS-275) in combination with a pan CA inhibitor, acetazolamide (AZ) on NB SH-SY5Y, SK-N-SH and SK-N-BE(2) cells. The key observation was that the combination AZ + MS-275 significantly inhibited growth, induced cell cycle arrest and apoptosis, and reduced migration capacity of NB cell line SH-SY5Y. [2]

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The aim of the present study was to determine whether acetazolamide (Ace) treatment enhances the chemosensitivity of Hep-2 laryngeal cells to cisplatin (Cis). At the logarithmic growth phase, Hep-2 cells were treated with Ace, Cis or both, and cell viability was detected using an MTT assay. The degree of apoptosis was detected using flow cytometry. Expression levels of apoptosis-related proteins, including BCL2 apoptosis regulator (bcl-2), BCL2 associated X (bax) and caspase-3, and of proliferation-related proteins, including proliferating cell nuclear antigen (PCNA) and tumor protein p53 (P53), were detected using western blotting. mRNA expression levels of aquaporin-1 (AQP1) in each group were detected using reverse transcription-polymerase chain reaction. Compared with the drugs used alone, treatment with both Ace and Cis displayed synergistic effects on the growth inhibition and apoptosis induction in Hep-2 cells. The Ace/Cis combination decreased the expression of PCNA but increased the expression of p53. In addition, the combination treatment decreased the ratio of bcl-2/bax and increased the expression of caspase-3, as well as decreased the expression of AQP1. These results demonstrated that the combined use of Ace and Cis enhanced the chemosensitivity of laryngeal carcinoma cells.[3]

Acetazolamide (40 mg/kg) significantly increased the inhibitory impact of MS-275 on tumorigenesis of neuroblastoma (NB) SH-SY5Y xenografts [3]. Sodium acetazolamide (40 mg/kg) and/or MS-275. Acetazolamide (40 mg/kg), MS-275 and Acetazolamide+MS-275 diminish mitosis in NB SH-SY5Y xenografts and treatable reduction of HIF1-α and CAIX expression in NB SH-SY5Y xenografts [3]. Expression of edema markers [3]. Acetazolamide sodium (50 mg/kg; PO for 3 days) effectively lowers gonococcal load in infected oral cavity by 90% [6].

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Gonococcal infections represent an urgent public health threat worldwide due to the increasing incidence of infections that has been accompanied by an increase in bacterial resistance to most antibiotics. This has resulted in a dwindling number of effective treatment options. Undoubtedly, there is a critical need to develop new, effective anti-gonococcal agents. In an effort to discover new anti-gonococcal therapeutics, we previously identified Acetazolamide, a carbonic anhydrase inhibitor, as a novel inhibitor of Neisseria gonorrhoeae. Acetazolamide exhibited potent anti-gonococcal activity in vitro as it inhibited growth of strains of N. gonorrhoeae at concentrations that ranged from 0.5 to 4 μg/mL. The aim of this study was to investigate the in vivo efficacy of acetazolamide in a mouse model of N. gonorrhoeae genital tract infection. Compared to vehicle-treated mice, acetazolamide significantly reduced the gonococcal burden by 90% in the vagina of infected mice after three days of treatment. These results indicate that acetazolamide warrants further investigation as a promising treatment option to supplement the limited pipeline of anti-gonococcal therapeutics.[6]

AlamarBlue cytotoxicity assay [2]
Standard protocol was performed as describe. Percent survival vs. control (DMSO- 0.2x10−4μM) of cells when treated with Acetazolamide (AZ) , MS-275 and AZ + MS-275 were observed using AlamarBlue agent agent (10% of total volume) was added to each well for 4 h before fluorometric detection. Fluorescence was measured using the SPECTRAmax Gemini Spectrophotometer (excitation 540 nm; emission 590 nm).

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Propidium Iodide cell cycle assay [2]
Briefly, 2 × 106 cells treated with Acetazolamide (AZ) and/or MS-275 were lifted by citrate saline and fixed in 80% ice-cold ethanol for 48 h. Cells were then pelleted and re-suspended in 2 mg/mL RNase A for 5 min. A 0.1 mg/mL propidium iodide solution was added, incubated for 30 min at RT, and cells filtered through a cell-strainer into a 5 mL polystyrene tube. Labeled cells were analyzed on a BD FACSCAN flow cytometer. Data was fitted by the Watson-Pragmatic model on FlowJo Software.

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Wound healing assay [2]
SH-SY5Y cells were seeded in a 48-well plate on glass cover slips and allowed to adhere overnight at a density of 105 cells/well in 500 μl culture medium in triplicate. Wells were marked with a straight black line on the bottom for orientation. At the time of 90% confluence, cell monolayers were scratched with a 200 μl pipette tip using the marker guide. Loosened non-adherent cells were washed off with medium. Fresh medium was added to the cultures with additions of Acetazolamide (AZ) (10 μM, 20 μM, 40 μM) and MS-275 (0.75 μM, 1.5 μM and 3 μM) and cultured for 48 h. After the 48 h period cells were washed with PBS and fixed in 4% paraformaldehyde. After three washes in PBS, cells were stained with 1% Crystal violet in 20% methanol. Phase contrast light microscopic images (10x original magnification) were taken at time points of 0, 48 and 72 h of treatment. Migrated cells were counted manually to quantify numbers of cells migrated to wound area using NIH Image J program. Each experiment was conducted three times in triplicate and one representative assay is shown.

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For the drug treatments, Hep-2 cells were treated with Acetazolamide (ACE) (a low concentration of 1×10−8 mol/l, termed here Acetazolamide (ACE)L; or a high concentration of 5×10−8 mol/l, termed here AceH), Cis (1 µg/ml) alone, or Cis in combination with Ace (AceL+Cis, or AceH+Cis) for 48 h. Cells that were treated with equal volumes of vehicle were used as control. Ace was used at 1×10−8 or 5×10−8 mol/l in all experiments. Cis was used at 1 µg/ml in all experiments. Both Cis and Ace were dissolved in dimethyl sulfoxide (DMSO) and then added to PBS to dilute to the final working concentrations. The final concentration of DMSO in cultures did not exceed 0.5%. HUVECs were treated with AceH alone, Cis alone or in combination (AceH+Cis) or control (vehicle) for 48 h.[3]

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Annexin V apoptosis assay [3]
Quantification of apoptotic cells was performed by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining using a FITC-Annexin V Apoptosis Detection kit. At the logarithmic growth phase, Hep-2 cells were placed in 6-well plates. The cells were treated with Acetazolamide (ACE)L, AceH, Cis, AceL+Cis, AceH+Cis, or vehicle for 48 h. Then, cells were washed in PBS, digested with trypsin, and resuspended in calcium-enriched HEPES buffer. This suspension was stained with Annexin V-FITC and PI for 15 min, as per the manufacturer's instructions. Finally, the cells were analyzed by FlowJo software.

Xenograft studies for determining the in vivo efficacy of Acetazolamide (AZ) , MS-275, and Acetazolamide (AZ)  + MS-275 combination [2]
For the in vivo xenograft study, 4–6 weeks-old female NOD/SCID mice were obtained from the animal facility. Subcutaneous xenograft tumors were developed by injecting SH-SY5Y cells (2 × 106) into the inguinal fat pad of NOD/SCID mice. When tumor diameter reached 0.5 cm, the mice were randomized into four groups (5 mice per group). The control and treatment groups received intraperitoneal injections of vehicle (PBS) or Acetazolamide (AZ) (40 mg/kg), MS-275 (20 mg/kg) or the combination, respectively, every day for 2 weeks. Experiments were terminated when tumor sizes exceeded 2 cm3 in volume or animals showed signs of morbidity. Tumor diameters were measured on a daily basis until termination. The long (D) and short diameters (d) were measured with calipers. Tumor volume (cm3) was calculated as V = 0.5 × D × d2. After euthanizing the mice, tumors were resected, weighed and fixed in 10% neutral-buffered formalin at room temperature and processed for histopathology. For the in vivo serial heterotransplantation analysis, 2x106 untreated and pretreated Acetazolamide (AZ)  + MS-275 cells, manually and enzymatically dissociated from treated tumors, were injected subcutaneously to NOD/SCID mice. Growth rates were measured 2–3 times per week. On the 38th day, the animals were sacrificed, after which tumors were removed and weighed.

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Mice infection and treatment [6]
Two days after pellet implantation (Day 0), the vagina of each mouse was rinsed with 50 mM HEPES (pH = 7.4), and each mouse was inoculated intravaginally with 20 μL of the prepared bacterial suspension of N. gonorrhoeae FA1090 (1.2 × 108 CFU/mL). Two days post-infection (Day +2), mice were randomly allocated into groups (n=10) and administered either Acetazolamide (50 mg/kg) or the vehicle (DMSO-Tween 80-PBS, 1:1:8) orally for three consecutive days. As a positive control, one group of mice was administered a single intraperitoneal dose of ceftriaxone (15 mg/kg in water).

Absorption, Distribution and Excretion
Carbonic anhydrase inhibitors bind tightly to carbonic anhydrase; therefore, after systemic administration, the concentration of carbonic anhydrase inhibitors in tissues rich in this enzyme will be higher. /Carbonic Anhydrase Inhibitors/
Carbonic anhydrase inhibitors. Drug: Acetazolamide; Oral absorption: Almost complete; Plasma half-life: 6–9 hours; Elimination route: Complete renal excretion. /Excerpt from Table/
Acetazolamide response in rabbits; renal response was measured by monitoring urine flow and sodium excretion, which occurred immediately after injection and were logarithmically related to the dose.
Intravenous bolus injection of (14)C-labeled acetazolamide was performed in rabbits. Drug concentrations in plasma, urine, and washed red blood cells were determined, with washed red blood cell concentration indicating drug binding.
For more data on the absorption, distribution, and excretion (complete) of acetazolamides (6 in total), please visit the HSDB record page.

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Metabolism/Metabolites
Acetazolamide dose does not alter metabolism.

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Biological half-life
3 to 9 hours
Plasma half-life: 6-9 hours /from table/

Toxicity Summary
Identification: Acetazolamide is a synthetic drug. Acetazolamide is a white to pale yellowish-white odorless crystalline powder. Acetazolamide is slightly soluble in water and slightly soluble in ethanol (approximately 750 g/L); practically insoluble in ether and chloroform. Uses: Preoperative management of angle-closure glaucoma or as an adjunct to the treatment of open-angle glaucoma. Abnormal Fluid Retention: Drug-induced edema, obesity, and congestive heart failure. Epilepsy. Metabolic alkalosis. Periodic paralysis. Human Exposure: Acute or chronic acetazolamide overdose may cause dehydration symptoms such as thirst, drowsiness, confusion, poor skin turgor, and prolonged capillary refill time, but paradoxical persistent diuresis may also occur. Electrolyte disturbances, including hyponatremia, hypokalemia, and non-anion intermittent hyperchloremic metabolic acidosis, especially at moderate to high doses, may lead to further deterioration of mental status, seizures, ECG abnormalities, and arrhythmias. Pre-existing renal insufficiency increases toxicity at the same dose. Specific reactions exist, leading to bone marrow suppression and hepatic and renal insufficiency. Acetazolamide may also precipitate in the renal tubules, forming stones and causing renal colic. Hypokalemia may cause muscle weakness, decreased reflexes, and hypochloremic metabolic alkalosis. In elderly patients, chronic metabolic acidosis may lead to chronic compensatory hyperventilation, increasing pulmonary vascular resistance and reducing left ventricular function. This is particularly important in patients taking beta-blockers or calcium channel blockers concurrently. The ventricular fibrillation threshold may be lowered. Potassium deficiency may cause arrhythmias. Abuse or overdose may cause pancreatitis. Acute overdose or prolonged use or abuse may cause hyperglycemia, hyperuricemia, and hyperlipidemia. Hypersensitivity reactions such as rash, photosensitivity, thrombocytopenia, and pancreatitis are rare. Contraindications: Renal hyperchloremic acidosis. Addison's disease and all types of adrenal insufficiency. Known sodium and potassium deficiency (at least before treatment). Long-term use is contraindicated in patients with chronic angle-closure glaucoma. It is also contraindicated in patients with known hypersensitivity to sulfonamides. Acetazolamide should not be used to alkalinize urine after a salicylate overdose, as it may exacerbate metabolic acidosis. Acetazolamide is readily absorbed from the gastrointestinal tract. It is distributed throughout the body; primarily concentrated in erythrocytes, plasma, and kidneys, with smaller amounts concentrated in the liver, muscles, eyes, and central nervous system. Acetazolamide does not accumulate in tissues. This drug can cross the placenta in unknown amounts. Acetazolamide binds tightly to carbonic anhydrase, resulting in higher concentrations in tissues containing this enzyme, such as erythrocytes and the renal cortex. Small amounts of acetazolamide undergo irreversible binding to erythrocytes. Its binding to plasma proteins is 70% to 90%. Acetazolamide is not metabolized. It is primarily excreted unchanged via the kidneys through renal tubular secretion and passive reabsorption. Although small amounts of the unchanged drug are excreted in bile, there is no evidence of enterohepatic circulation. Acetazolamide is a carbonic anhydrase inhibitor. Acetazolamide reduces the availability of these ions for active transport to secretions by non-competitive, reversible inhibition of carbonic anhydrase, decreasing the process by which carbon dioxide and water generate hydrogen and bicarbonate ions. One patient died of cholestatic jaundice after taking 13 grams of acetazolamide over 26 days. Another patient developed fatal bone marrow suppression with leukopenia, thrombocytopenia, and anemia after 14 weeks of acetazolamide treatment. Yet another patient developed renal failure (anuria) after 2 weeks of acetazolamide use. Despite its widespread use, no birth defects have been reported with acetazolamide. However, a woman who took 750 mg/day of acetazolamide for glaucoma during early and mid-pregnancy gave birth to an infant with a sacrococcygeal teratoma, but a causal relationship could not be established. Teratogenicity studies in rats and mice showed that the offspring of rats and mice were missing the fourth and fifth toes on the right forelimb. No obvious lesions were observed in newborn rabbits and monkeys. The drug can cross the placenta in unknown amounts. Potentially dangerous interactions: Acetazolamide may enhance the effects of folic acid antagonists, oral hypoglycemic agents, and oral anticoagulants. Acetazolamide can inhibit the urinary disinfectant effect of methylamine by maintaining urine alkalinity. Acetazolamide alkalinizes urine, reducing the urinary excretion of many weak bases (including amphetamine, quinine, quinidine, and ethamazol), thereby enhancing their pharmacological effects. Drug-induced osteomalacia has been reported in a patient taking phenytoin sodium and acetazolamide. More serious side effects include blood disorders, skin toxicity, and kidney stone formation. There have been no reports of Stevens-Johnson syndrome. Symptomatic adverse reactions: Flushing, thirst, headache, somnolence, dizziness, fatigue, irritability, excitement, paresthesia, ataxia, tachypnea, and gastrointestinal disturbances (Dollery) have been reported. Oral administration is the common route of exposure. There is no significant skin absorption. There is no significant absorption or local irritation. Animal/Plant Studies: Numerous animal studies have shown that acetazolamide has extremely low toxicity in the studied species (mice, dogs, rats, monkeys). International Programme for Chemical Safety; Toxic Information Monograph: Acetazolamide (PIM 005) (1995) is available as of May 16, 2008 at: https://www.inchem.org/pages/pims.html

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Effects during pregnancy and lactation
◉ Overview of use during lactation
Limited information suggests that low levels of acetazolamide in breast milk, even when the mother takes up to 1000 mg daily, are not expected to have any adverse effects on the breastfed infant. Professional guidelines in the United States, Canada, and France consider carbonic anhydrase inhibitors acceptable during breastfeeding.
◉ Effects on Breastfed Infants
One mother received 500 mg of diamox sequels twice daily. Her breastfed infant (feeding extent unspecified) did not experience any significant acetazolamide-related adverse events between days 6 and 10 postpartum.
One mother received 250 mg of diamox sequels orally twice daily, along with two drops of 0.5% timolol eye drops and two drops of pilocarpine eye drops daily. The infant was delivered preterm at 36 weeks of gestation. Exclusive breastfeeding began 6 hours after birth and lasted 5 months. On day 2 postpartum, the infant developed electrolyte disturbances, including hypocalcemia, hypomagnesemia, and metabolic acidosis. The infant received oral calcium gluconate and a single intramuscular injection of magnesium sulfate. Despite continued breastfeeding and maternal medication, the infant's mild metabolic acidosis resolved on day 4 postpartum, and weight gain was normal at 1, 3, and 8 months, although mild hypotonia was present. The authors believe this metabolic effect is caused by the transplacental transport of acetazolamide, and this effect subsided despite breastfeeding. The infants gained weight well during breastfeeding, but had mild residual hypertonia in the lower extremities requiring physical therapy. Two women took acetazolamide during pregnancy and postpartum due to idiopathic intracranial hypertension. Both of their infants developed metabolic acidosis after birth. The metabolic acidosis in both infants was relieved by breastfeeding. ◉ Effects on lactation and breast milk: A randomized, partially blinded trial compared the effects of four treatment regimens on 243 mothers who did not wish to breastfeed: one acetazolamide tablet daily (estimated at 250 mg), 0.5 mg diethylstilbestrol twice daily, a placebo once daily, and routine care. Pain and breast engorgement were assessed at least daily by blinded observers. At these doses, acetazolamide was not more effective than placebo in relieving discomfort and was slightly less effective than diethylstilbestrol.

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Protein binding rate
98%

[1]. Acetazolamide potentiates the anti-tumor potential of HDACi, MS-275, in neuroblastoma. BMC Cancer. 2017 Feb 24;17(1):156.

[2]. Dual-tail approach to discovery of novel carbonic anhydrase IX inhibitors by simultaneously matching the hydrophobic and hydrophilic halves of the active site. Eur J Med Chem. 2017 May 26;132:1-10.

[3]. Combined treatment with acetazolamide and cisplatin enhances chemosensitivity in laryngeal carcinoma Hep-2 cells. Oncol Lett. 2018 Jun;15(6):9299-9306.

[4]. Acetazolamide: a forgotten diuretic agent. Cardiol Rev. 2011 Nov-Dec;19(6):276-8.

[5]. Interaction of antihypertensive acetazolamide with nonsteroidal anti-inflammatory drugs. J Photochem Photobiol B. 2013 Aug 5;125:155-63.

[6]. In vivo efficacy of acetazolamide in a mouse model of Neisseria gonorrhoeae infection. Microb Pathog. 2022 Mar;164:105454.

Acetazolamide sodium is an organic sodium salt composed of acetazolamide and acetazolamide (1-). Acetazolamide sodium is the sodium salt of acetazolamide, a non-bacteriostatic sulfonamide derivative with diuretic and anticonvulsant effects. Acetazolamide is a potent inhibitor of carbonic anhydrase, which plays an important role in controlling fluid secretion. Inhibition of this enzyme in the kidneys leads to a reduction in hydrogen ions available for active transport in the renal tubules, resulting in increased excretion of bicarbonate and cations, and increased urine output. Decreased circulating bicarbonate levels can lower intraocular pressure through osmotic mechanisms. The anticonvulsant activity of acetazolamide may be related to its inhibition of central nervous system carbonic anhydrase, thereby reducing the partial pressure of carbon dioxide in the alveoli and increasing the partial pressure of oxygen in the arteries.
See also: Acetazolamide (containing the active moiety).
Acetazolamide may cause developmental toxicity depending on state or federal labeling requirements.
Acetazolamide is a white to pale yellow fine crystalline powder, odorless and tasteless. (NTP, 1992)
Acetazolamide is a sulfonamide drug belonging to the thiadiazole class of monocarboxylic acid amides. It has diuretic, anticonvulsant, and carbonic anhydrase inhibitory effects (EC 4.2.1.1). It is the conjugate acid of acetazolamide (1-). It is derived from the hydrogenation of 1,3,4-thiadiazole.
Acetazolamide is a carbonic anhydrase inhibitor, sometimes effective for absence seizures. It is sometimes used as adjunctive therapy for tonic-clonic, myoclonic, and atonic seizures, especially in women whose seizures occur or worsen during specific periods of the menstrual cycle. However, its efficacy is often transient due to rapid development of tolerance. Its antiepileptic effect may stem from its inhibition of brain carbonic anhydrase, leading to an increase in the transneuronal chloride ion gradient, an increase in chloride ion current, and enhanced inhibition. (Quoted from Smith and Reynard, Textbook of Pharmacology, 1991, p. 337)
Acetazolamide is a carbonic anhydrase inhibitor. Acetazolamide's mechanism of action is as a carbonic anhydrase inhibitor. Acetazolamide is a sulfonamide derivative with diuretic, anti-glaucoma, and anticonvulsant effects. It is a non-competitive inhibitor of carbonic anhydrase, an enzyme found in proximal tubular cells of the kidneys, ocular cells, and glial cells. Inhibition of this enzyme in the kidneys prevents hydrogen excretion, thereby increasing the excretion of bicarbonate and cations, increasing urine volume, and ultimately leading to alkaline diuresis. Acetazolamide reduces bicarbonate concentration, resulting in reduced aqueous humor synthesis and thus lowering intraocular pressure. Although its mechanism of action is not fully understood, acetazolamide's anticonvulsant effect may be due to indirect effects of metabolic acidosis or direct effects on neurotransmission. Acetazolamide also has a respiratory stimulant effect on changes in intrapulmonary carbon dioxide and oxygen tension levels. It is one of the carbonic anhydrase inhibitors and is sometimes effective for absence seizures. It can sometimes be used as adjunctive therapy for tonic-clonic seizures, myoclonic seizures, and atonic seizures, especially in female patients whose seizures occur or worsen during specific periods of the menstrual cycle. However, its efficacy is often transient due to rapid tolerance development. Its antiepileptic effect may stem from its inhibition of cerebral carbonic anhydrase, leading to an increase in the transneuronal chloride gradient, chloride current, and enhanced inhibition. (Quoted from Smith and Reynard, Pharmacology Textbook, 1991, p. 337)
See also: Acetazolamide sodium (salt form); Acetazolamide disodium (its active ingredient).
Indications

For adjunctive treatment of: edema due to congestive heart failure; drug-induced edema; central epilepsy; chronic simple (open-angle) glaucoma.
FDA Label

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Mechanism of Action
The anticonvulsant activity of acetazolamide may depend on the direct inhibition of carbonic anhydrase in the central nervous system, thereby reducing the partial pressure of carbon dioxide in the alveoli and increasing the partial pressure of oxygen in the arterial blood. Its diuretic effect depends on the inhibition of carbonic anhydrase, leading to a reduction in hydrogen ions available for active transport in the renal tubules. This results in alkaline urine and increased excretion of bicarbonate, sodium, potassium, and water.
Carbonic anhydrase inhibitors potently inhibit both membrane-bound and cytoplasmic carbonic anhydrases (acetazolamide IC50 is 10 nM), thereby almost completely blocking the reabsorption of NaHCO3 in the proximal tubules. /Carbonic Anhydrase Inhibitors/
Although the proximal tubules are the primary site of action for carbonic anhydrase inhibitors, carbonic anhydrase is also involved in the secretion of titratable acids in the collecting duct system (a process involving proton pumps), therefore the collecting duct system is a secondary site of action for this type of drug. /Carbonic Anhydrase Inhibitors/
Acetazolamide often causes paresthesia and drowsiness, suggesting that carbonic anhydrase inhibitors may act on the central nervous system. The efficacy of acetazolamide in treating epilepsy is partly attributed to the metabolic acidosis it causes; however, its direct effects on the central nervous system also contribute to its anticonvulsant effect.
…Inhibition of carbonic anhydrase reduces the rate of aqueous humor production, thereby lowering intraocular pressure. /Carbonic Anhydrase Inhibitors/
For more complete data on the mechanisms of action of acetazolamides (6 in total), please visit the HSDB record page.
Acetazolamide is the only carbonic anhydrase inhibitor with a significant diuretic effect. It is readily absorbed and excreted by the kidneys via tubular secretion. Its administration typically results in rapid alkaline diuresis. Although carbonic anhydrase inhibitors are proximal tubular diuretics (where sodium reabsorption mainly occurs), their net diuretic effect is not significant because sodium reabsorption in distal nephron segments offsets proximal sodium loss. The use of acetazolamide is limited by its short-lived effects and the potential for metabolic acidosis with prolonged use. However, acetazolamide can correct significant metabolic alkalosis that occasionally occurs during loop diuretic therapy. [3]

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This study investigated the binding of the antihypertensive drug acetazolamide with 11 nonsteroidal anti-inflammatory drugs (NSAIDs) at pH 3, 7, and 9.5 to monitor their pharmacokinetic interactions during human digestion and absorption. Results from UV-Vis spectroscopy and cyclic voltammetry showed that two NSAIDs (acetaminophen and sodium dichlorophenolate) interacted with acetazolamide under gastric conditions to form complexes with stoichiometric ratios of 1:1 and 1:2. These complexation ratios were also verified by calculations. The strong binding tendency of acetaminophen and sodium dichlorophenolate to acetazolamide limits their co-administration. However, the weaker binding affinity of aspirin and mefenamic acid suggests that these two drugs are preferred NSAIDs for co-administration with acetazolamide. [4]

C4H5N4O3S2-.NA+

244.2273

243.97

1424-27-7

Acetazolamide;59-66-5;Acetazolamide-d3;1189904-01-5

13290219

White to off-white solid powder

258-259ºC (EFFERVESCENCE)

0.783

2

7

2

14

302

0

MRSXAJAOWWFZJJ-UHFFFAOYSA-M

InChI=1S/C4H6N4O3S2.Na/c1-2(9)6-3-7-8-4(12-3)13(5,10)11;/h1H3,(H3,5,6,7,9,10,11);/q;+1/p-1

sodium;(5-acetamido-1,3,4-thiadiazol-2-yl)sulfonylazanide

Acetazolamide sodium; Sodium acetazolamide; 1424-27-7; Acetazolamide sodium salt; CHEBI:31163; 429ZT169UH; sodium;(5-acetamido-1,3,4-thiadiazol-2-yl)sulfonylazanide; N-(5-Sulfamoyl-1,3,4-thiadiazol-2-yl)acetamide monosodium salt;

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment, 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)

H2O : ≥ 100 mg/mL (~407.76 mM)
DMSO : ~100 mg/mL (~407.76 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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