Acetazolamide-N,d , CAS No.1261393-93-4

CAS: 1261393-93-4 Cat. No.: A1440481 Formula: C₄H₃D₃N₃₁₅NO₃S₂ Molecular Weight: 226.26

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Overview

Acetazolamide- 15 N,d3 is the 15 N and deuterium labeled isotope of Acetazolamide( 15 N,d3).

Specifications

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

This product requires cold chain shipping. Ground and other economy services are not available.

Names and Identifiers

Molecular Weight

226.26

Application Protocols

The following generalized protocol outlines use of Acetazolamide‑N,d as an internal standard for LC‑MS/MS quantitation of acetazolamide in biofluids. Adjust to your instrumentation and SOPs. Item‑specific parameters are not provided and should be validated in‑house.

• Materials:

  • Acetazolamide‑N,d stock solution (e.g., 1 mg/mL in DMSO or MeOH; prepare gravimetrically).
  • Mobile phases: A = water + 0.1% formic acid (or 5 mM ammonium formate), B = acetonitrile.
  • Calibrator/QC matrices (e.g., K2‑EDTA plasma) and neat solvents for standards.

• Stock and working IS:

  • Prepare primary stock; store at −20 °C. Prepare a working IS at 100–1000 ng/mL in MeOH or ACN and store at 2–8 °C for short term.

• Sample preparation (protein precipitation example):

  1. Aliquot 50–100 µL of matrix into microcentrifuge tubes.
  2. Add fixed volume of working IS to each tube (to achieve 10–100 ng/mL final in extract).
  3. Add 3–4 volumes of cold ACN (or MeOH), vortex 60–120 s.
  4. Centrifuge at ≥10,000 g for 10–15 min; transfer supernatant.
  5. Dilute with water/mobile phase if needed; inject 1–10 µL.

• LC‑MS/MS:

  • Use reversed‑phase C18; gradient 5→60% B over 5–8 min. Monitor MRM transitions for both analyte and labeled IS (set from CoA or empirical optimization).
  • Quantitation: weighted linear regression (1/x or 1/x^2); include ≥6 non‑zero calibrators and low/medium/high QCs.

All steps are for research use only; verify recovery, matrix effects, stability, and carryover per bioanalytical validation best practices.

Biological Roles

Information below describes the biological role of the parent compound acetazolamide (literature context). It is provided to guide research use of the isotopically labeled standard and does not imply any therapeutic or clinical application of this product.

• Molecular target (literature): acetazolamide is a classical inhibitor of carbonic anhydrase (CA) isoforms, coordinating the active‑site Zn2+ via its deprotonated sulfonamide. Inhibition perturbs reversible hydration of CO2 to bicarbonate and protons.
• Mechanistic features:
  • The primary sulfonamide is the pharmacophore, forming a Zn–NH− bond in CA active sites; the 1,3,4‑thiadiazole ring and acetamide contribute to binding orientation and affinity.
  • Microenvironmental pH and protein isoform sequence modulate potency; distinct CA isoforms (e.g., CA II, CA IV, CA IX) have differing affinities (literature).
• Biochemical consequences (research context): alterations in cellular pH regulation, bicarbonate transport coupling, and downstream effects on ion transport and metabolism in systems expressing carbonic anhydrases.
• Use of isotopologues in biology:
  • Labeled standards enable accurate quantification of acetazolamide exposure in in vitro and ex vivo studies, facilitating correlation of concentration with observed biochemical effects.
  • Stable‑isotope labeling is also advantageous in metabolism studies (e.g., monitoring potential deacetylation or conjugation) by distinguishing parent from background interferences.

Note: No medical/clinical claims are made for this item. All uses are for research and laboratory investigation only.

Buffer Applications

This product is a small‑molecule isotopically labeled standard and is not itself a buffering agent. Accordingly:

• It is not typically used to prepare buffer systems or to control pH.
• For assay work, select buffers that support acetazolamide solubility and target protein stability (e.g., ammonium formate/acetate for LC‑MS compatibility, or phosphate for biochemical assays). Maintain organic co‑solvent content at levels that prevent precipitation while preserving chromatographic performance.

Refer to Solvent Selection and Application Protocols for practical guidance relevant to LC‑MS workflows.

Green Alternatives

As an isotopically labeled reference material, the choice of greener alternatives pertains mainly to solvent systems and sample‑prep strategies rather than to the analyte itself.

• Greener solvent considerations (general):

  • Prefer acetonitrile or ethanol over halogenated solvents when feasible; avoid dichloromethane/chloroform in routine workflows.
  • Use aqueous mobile phases with low percentages of organic modifier; formic acid (0.1%) is generally adequate for LC‑MS.
  • For dissolution, ethanol or methanol can substitute for DMSO in some cases, improving volatility and EHS profile—confirm solubility first.

• Sample preparation:

  • Favor protein precipitation (MeOH or ACN) or dilute‑and‑shoot methods over LLE with non‑green solvents, provided matrix effects remain controlled.
  • Solid‑phase extraction using water/ACN or water/MeOH eluents can reduce halogenated solvent usage.

• Operational green practices:

  • Minimize stock concentration to what is necessary for accuracy to reduce DMSO volume in final injectables (<1% v/v recommended).
  • Consolidate runs and use microflow LC‑MS where appropriate to reduce solvent consumption.

Tradeoffs: DMSO offers superior solvating power and chemical stability for many analytes, including acetazolamide; switching to greener solvents may require sonication, longer dissolution times, or slightly warmer temperatures (avoid exceeding analyte stability limits).

Pharmaceutical Uses

No therapeutic or clinical claims apply to this product. In a research and development context, isotopically labeled acetazolamide standards are used as analytical tools rather than as actives or excipients.

• Research/formulation analytics (general):

  • Internal standard in stability‑indicating LC or LC‑MS methods for drug‑substance/drug‑product development of acetazolamide, supporting impurity profiling and degradation studies.
  • Tool compound for extraction recovery studies from complex matrices (e.g., tablet blends, polymer matrices) to validate sample preparation.
  • Reference for in vitro release testing (IVRT) or dissolution method development where quantitation of acetazolamide is required; the labeled IS can correct for matrix effects.

• Regulatory context:

  • Stable‑isotope standards are commonly included in method validation packages (selectivity, accuracy, precision, recovery, matrix effects). The specific isotopic labeling details, purity, and stability must be documented via CoA.

• Manufacturing QC support:

  • Spike‑and‑recover experiments to assess ruggedness across analysts/instruments.

All uses are for laboratory research and analytical method development. This item is not intended for human or animal use.

Physical Properties

• Item‑specific properties (this SKU):

  • Appearance: Not specified for this item; refer to CoA/Spec Sheet.
  • Grade/Purity: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet (depends on isotope count).
  • Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.

• Parent compound (acetazolamide) — typical literature values provided for context only (unlabeled):

  • Melting point: ~258–260 °C (decomp., literature).
  • LogP (octanol/water): ~−0.1 to 0.1 (literature, method‑dependent), reflecting modest polarity with limited aqueous solubility at neutral pH.
  • pKa values: sulfonamide NH pKa ~7.2–7.6; acetamide is non‑basic (literature). Ionization and micro‑pKa can shift with medium/ionic strength.
  • Aqueous solubility: low at neutral pH; solubility increases in basic media and in polar aprotic solvents (literature). Common laboratory stock solutions are prepared in DMSO or DMF.

• Refractive index, density, UV cutoff: Not specified for this item; refer to CoA/Spec Sheet.

• Practical notes for isotopologues (general):

  • Isotopic substitution (15N, 2H) minimally perturbs bulk thermophysical properties but alters exact mass and often retention time slightly in LC due to isotope effects (notably for multiple deuteriums).
  • For LC‑MS, confirm monoisotopic m/z from CoA to set transitions and exact‑mass filters.

All property values that govern suitability for your method (solubility, exact mass, purity) should be verified on the lot‑specific CoA/SDS before use.

Quality & Grades

• Item‑specific grade/purity: Not specified for this item; refer to CoA/Spec Sheet.
• Context for isotopically labeled reference standards (general):
  • Isotopic enrichment: For LC‑MS internal standards, enrichment at specified positions (e.g., 15N, 2H) ensures mass separation from the analyte. The enrichment percentage and labeling pattern define utility and should be confirmed on the CoA.
  • Chemical purity vs. isotopic purity: Both matter. Chemical purity governs chromatographic cleanliness and matrix effects; isotopic purity governs interference from partially unlabeled species.
  • Residual solvents, water content, and counter‑ions (if any) can influence measured concentration in solution; consult CoA for accurate assay values.
• Stabilizers: Not specified for this item; refer to CoA/Spec Sheet. Many neat labeled standards are shipped without stabilizer; if present, it will be declared on the CoA.
• Suitability notes (general guidance):
  • For quantitative LC‑MS/MS, a mass shift of ≥3 Da is commonly targeted to minimize overlap with natural isotopic clusters; verify that the N,d labeling here provides sufficient separation for your method’s resolution and collision settings.
  • If using for isotope‑dilution quantitation, confirm lot‑specific purity and precise concentration following gravimetric preparation of stocks.
• Documentation: Lot‑resolved CoA typically includes structure (with isotopic positions), exact mass, isotopic enrichment, chemical purity, and recommended handling. Request these documents for method validation files.

Reaction & Applications

Given its designation as Acetazolamide‑N,d, this material is best understood as an isotopically labeled analytical standard rather than a synthetic reagent.

• Primary research applications (general for labeled small‑molecule standards):

  • Internal standard for quantitative LC‑MS/MS assays of acetazolamide in preclinical matrices (plasma, serum, tissue homogenates) and in in vitro systems (hepatocyte or microsomal incubations).
  • Tracer in metabolic stability, microsomal clearance, and protein‑binding studies (isotope‑dilution–based quantitation).
  • Recovery and matrix‑effects normalization during sample preparation (protein precipitation, SPE, LLE) in bioanalytical method development.
  • Potential use in binding or inhibition assays targeting carbonic anhydrases, allowing parallel quantification of bound/free fractions.

• Practical method notes:

  • Select multiple reaction monitoring (MRM/PRM) transitions based on the isotopologue’s exact mass shift; avoid overlap with the unlabeled analyte’s natural isotope distribution.
  • Co‑elution of the labeled IS with acetazolamide is preferred; deuterium labeling can impart slight retention shifts—evaluate chromatographic conditions (e.g., gradient strength, stationary phase) to maintain close co‑elution.
  • Calibrate using matched matrix calibrators and back‑calculate with weighted regressions (e.g., 1/x or 1/x^2) typical for LC‑MS bioanalysis.

• Not typically used for: general organic synthesis or as a stoichiometric reagent. If synthetic manipulation is intended (e.g., prodrug studies), verify labeling positions to avoid isotope loss during transformation.

Reaction Conditions

Conventional synthetic reaction conditions are not typically applicable to this product’s intended use. Instead, the most relevant “conditions” concern LC‑MS analytical operation for which the labeled standard is employed (general literature guidance):

• LC conditions:

  • Columns: C18 or phenyl‑hexyl reversed‑phase; consider polar‑embedded phases to improve peak shape for moderately polar sulfonamides.
  • Mobile phases: water with 0.1% formic acid or ammonium formate (2–10 mM) and acetonitrile or methanol as organic modifier.
  • Gradients: shallow to moderate (5–60% organic over 3–8 min) to ensure co‑elution of labeled IS and analyte.

• MS conditions:

  • Ionization: ESI in negative or positive mode can be viable; many sulfonamides respond well in negative ESI. Optimize source parameters (capillary voltage, desolvation temp/flow) empirically.
  • Transitions: select precursor m/z corresponding to labeled exact mass; fragment to characteristic ions (e.g., losses from sulfonamide/amide moieties). Obtain recommended transitions from CoA or in‑house optimization.

• Sample preparation (typical ranges):

  • Internal standard spike: add fixed concentration (e.g., 10–100 ng/mL) to all calibrators, QCs, and unknowns before extraction.
  • Extraction: protein precipitation with 3–4 volumes of ACN or MeOH, vortex 1–2 min, centrifuge 10–15 min at ≥10,000 g; dilute/transfer supernatant for injection.

These conditions are general guidance only. Optimize for your instrument, matrix, and sensitivity targets.

Safety & Handling

• GHS classification, signal word, hazard statements, and pictograms: Not specified for this item; refer to SDS.
• General laboratory precautions (good practice for small‑molecule sulfonamides; informational, not a substitute for SDS):
  • Use in a chemical fume hood; avoid inhalation of dust/aerosols and contact with skin/eyes.
  • Wear appropriate PPE: lab coat, safety glasses, and suitable chemical‑resistant gloves (e.g., nitrile). Wash thoroughly after handling.
  • Avoid generating dust; handle solids gently. For solutions, cap/label clearly and prevent contact with incompatible reagents (strong oxidizers, strong bases/acids that may cause hydrolysis or degradation).
  • Though not a peroxide‑forming class, dry powders can be irritants; manage spills with damp disposable wipes or HEPA vacuum designed for fine powders.
• First‑aid overview (consult SDS for details):
  • Inhalation: move to fresh air; seek medical attention if symptoms occur.
  • Skin/eye contact: rinse with water for at least 15 minutes; remove contaminated clothing; seek medical attention for persistent irritation.
  • Ingestion: rinse mouth; do not induce vomiting unless directed by medical personnel; seek medical advice.
• Fire safety: Most organic solids may burn. Use CO2, dry chemical, or foam. Thermal decomposition can release sulfur/nitrogen oxides.
• Waste: Collect in properly labeled organic waste per institutional and regulatory guidance.
• Storage per item data: Store at −20 °C (desiccated, protected from light if feasible). Shipments are provided cold (ice chest + ice pads) to preserve integrity. Always defer to the product’s SDS and CoA for authoritative hazard and handling information.

Solvent Selection

This product is a small‑molecule isotopologue of acetazolamide; dissolution behavior generally follows the parent compound.

• Solubility tendencies (literature, parent compound):

  • Water (neutral pH): low solubility; solubility improves in mildly basic aqueous media due to deprotonation of the sulfonamide.
  • Polar aprotic: DMSO and DMF provide excellent solubility and are commonly used for stock solutions (e.g., 1–10 mM).
  • Alcohols: limited to moderate solubility in methanol/ethanol; verify experimentally.
  • Nonpolar solvents (e.g., hexanes, toluene): poor solubility.

• Practical choices for analytical workflows:

  • LC‑MS/MS: Prepare primary stocks in anhydrous DMSO or MeOH, then dilute into initial mobile phase (e.g., water/acetonitrile with 0.1% formic acid) to minimize precipitation.
  • For protein‑precipitation workflows: Use acetonitrile or methanol containing the internal standard; mix with biofluid at 3–4× volume, vortex, centrifuge, then inject supernatant.

• Comparison notes (general):

  • DMSO: highest solvating power; small injection volumes (<1% v/v of aqueous mobile phase) recommended to avoid chromatographic distortion.
  • Methanol: volatile and MS‑friendly; may require sonication for complete dissolution.
  • Acetonitrile: good for dilution/precipitation, but primary dissolution may be slower than in DMSO/MeOH.

Item‑specific solubility and solvent recommendations are not specified for this item; verify experimentally at small scale and consult the CoA.

Storage & Reconstitution

• Storage conditions (item‑specific): Store at −20 °C. Shipments are made in an ice chest with ice pads to maintain cold chain.

• General handling:

  • Allow container to equilibrate to room temperature in a desiccator before opening to minimize moisture condensation.
  • Immediately reseal under dry atmosphere after dispensing. For hygroscopicity and photostability, follow any additional guidance on the CoA/SDS.

• Reconstitution (general guidance for isotopically labeled small molecules):

  • Prepare primary stock gravimetrically in anhydrous DMSO or methanol at a convenient concentration (e.g., 0.5–1.0 mg/mL), then aliquot.
  • Filter through a PTFE syringe filter (0.2 µm) if particulate matter is observed.
  • Avoid repeated freeze–thaw: split into single‑use aliquots; store working solutions at 2–8 °C (days) or −20 °C (weeks), monitoring for precipitation or degradation.

• Stability notes:

  • Deuterium at exchangeable positions may undergo H/D back‑exchange in protic solvents; minimize prolonged exposure to water or alcohols at elevated temperature and neutral/alkaline pH if label integrity is critical.
  • Track solution stability by periodic LC‑MS/MS checks of response and exact mass; compare to freshly prepared standards.

Item‑specific stabilizers, concentration, water content, and purity are not specified for this item; consult the CoA/Spec Sheet for definitive guidance.

Structure & Identity

This catalog entry refers to an isotopically labeled form of acetazolamide designated “Acetazolamide‑N,d,” typically indicating incorporation of heavy isotopes at one or more nitrogen (15N) and hydrogen (2H, D) positions. Item‑specific isotopic positions and counts are not provided here.

• Item‑specific identifiers:

  • CAS: 1261393-93-4
  • InChIKey: Not specified for this item; refer to CoA/Spec Sheet.
  • SMILES: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
  • Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.

• Parent compound (acetazolamide) — literature identity for reference only:

  • Canonical structure: a 1,3,4‑thiadiazole ring bearing a sulfonamide (–SO2NH–) at C‑5 and an acetamide (–NH–C(O)CH3) at C‑2 (systematic name: N‑(5‑sulfamoyl‑1,3,4‑thiadiazol‑2‑yl)acetamide).
  • Molecular formula (unlabeled): C4H6N4O3S2 (literature).
  • Average molecular weight (unlabeled): ~222.25 g/mol (literature).
  • Key functional groups: sulfonamide, acetamide, heteroaromatic 1,3,4‑thiadiazole.

• Structural features described in 2D terms (literature):

  • A five‑membered ring containing N1–C2–N3–C4–S5 with a ring sulfur and two ring nitrogens (1,3,4‑thiadiazole).
  • At the ring C‑2 position, an anilide‑like amide linkage to an acetyl group.
  • At the ring C‑5 position, a primary sulfonamide (–SO2NH2) substituent.

Note: Exact isotopic labeling pattern and any consequent changes to average mass/monoisotopic mass for Acetazolamide‑N,d must be confirmed from the product’s CoA/Spec Sheet.

Synthetic Utility

Acetazolamide‑N,d is primarily intended as a stable‑isotope internal standard rather than a synthetic building block. Nevertheless, understanding parent compound functionality can assist in any exploratory derivatization or analytical degradation studies.

• Functional group profile (parent compound, literature):

  • Primary sulfonamide (acidic NH), capable of deprotonation and coordination to metal centers.
  • Secondary amide (acetamide), generally robust; can undergo hydrolysis under strong acidic/basic conditions.
  • 1,3,4‑thiadiazole heteroaromatic ring, typically resistant to mild conditions but susceptible to strong nucleophiles/electrophiles at activated positions.

• Analytical/synthetic implications:

  • Under forced‑degradation studies (ICH‑style), track hydrolytic cleavage of the acetamide or desulfonamidation; isotopic labels on N/H may move with fragments—verify label retention before designing pathways.
  • If isotopic integrity must be preserved, avoid exchange‑prone conditions for deuterium (e.g., strong base, protic solvents at elevated temperature) that can promote H/D back‑exchange at labile positions.

• Not typical for: cross‑couplings, Grignards, or reductive aminations in routine synthesis. Any transformation risks scrambling or loss of isotopic labels and is generally avoided when the compound’s role is as an internal standard.

Target Specificity

Item‑specific biological target data are not provided for this SKU. For research context, the parent compound acetazolamide is a well‑characterized inhibitor of carbonic anhydrase isoforms (literature). Key points:

• Molecular target (literature): carbonic anhydrases (zinc metalloenzymes) where the deprotonated sulfonamide coordinates Zn2+ at the active site.
• Isoform considerations: different CA isoforms exhibit varying affinities for acetazolamide due to differences in active‑site residues and access channels.
• Isotopic labeling impact: 15N/2H substitution does not meaningfully alter binding specificity but provides mass differentiation for analytical tracking.

No item‑specific binding constants, isoform selectivity data, or assay validation are supplied here; consult the primary literature and generate in‑house data under your assay conditions.

Frequently Asked Questions

How should this product be stored?

Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.

How is this product shipped?

This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.

What are the CAS number, molecular formula and molecular weight?

The CAS Number is 1261393-93-4, the molecular formula is C4H3D3N315NO3S2, and the molecular weight is 226.26 g/mol.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.