Isotope Science / Alfa Chemistry

Isotope-Labeled Inhibitors: Precision Tools for Advanced Research

Alfa Chemistry is a leading global supplier of stable isotope-labeled compounds, providing high-quality solutions for complex analytical challenges. Alfa Chemistry supplies an extensive catalogue of isotope-labeled inhibitors (13C, 15N, deuterium (2H, d), multi-label, salts and metabolites) suitable for LC–MS/MS internal standards, metabolic-flux/tracer studies, NMR, synthesis building blocks and click-chemistry reagents.

These high-purity isotope-labeled inhibitors from Alfa Chemistry serve as critical internal standards in quantitative mass spectrometry, tracers for dynamic metabolic flux analysis, and probes for sophisticated chemoproteomic studies. Our expansive portfolio encompasses hundreds of inhibitors across major therapeutic and research areas.

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Overview: Tracing the Pathway to Discovery

What Are Isotope-Labeled Inhibitors?

Isotope-labeled inhibitors are chemically identical (or near-identical) to a parent inhibitor but contain stable heavy isotopes such as 13C, 15N, or 2H (deuterium). These labeled compounds are used as internal standards for quantitative mass spectrometry, as tracers in metabolic flux experiments, for NMR sensitivity/assignment, and as synthetic building blocks or click-chemistry handles.

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Why Isotope-Labeled Inhibitors Matter?

The vast majority of these tools are used for ADME (absorption, distribution, metabolism, excretion) studies in vitro and in vivo. By incorporating a stable isotope label into the compound, the compound of interest can be distinguished from identical molecules that are endogenously present in a system. This allows unambiguous tracing of the metabolic fate of a drug, identification of its metabolites and detailed characterization of its pharmacokinetics, all of which underlie further research into mechanism of action, pathogenesis and synthetic biology.

What Do We Offer?

Our catalogue includes:

  • Single-isotope labels (e.g., 13C, 15N, D).
  • Multi-isotope labels (e.g., 13C + D or 13C + 15N).
  • Position-specific labels and uniformly labeled analogues.
  • Labeled metabolites and active metabolites (e.g., glucuronides, sulfonates).

Examples in our inventory: Ibuprofen-13C6, Osimertinib-13C,d3, Sacubitril-13C4, Rapamycin-13C,d3, and hundreds more.

Types of Isotope-Labeled Inhibitors

Our portfolio is organized by the type of isotope incorporated and the biological target below. The selection of isotope depends on the specific analytical needs and the molecular structure of the parent inhibitor.

Deuterium Labeling

Carbon-13 Labeling

Nitrogen-15 Labeling

Dual/Multi-Labeling

Representative Inhibitor Classes

Deuterium Labeling

  • Common Label: 2H (D)
  • Characteristics & Applications: Alters bond kinetics (Kinetic Isotope Effect), potentially modulating metabolic stability. Frequently used for ADME studies and the development of deuterated drugs.

Recommended Products:

CatalogNamePrice
ACM1260619564-1Abacavir-d4Inquiry
ACM2088650535Abemaciclib-d8Inquiry
ACM1356847567-1Argatroban-d3Inquiry
ACM1564241797-1Baricitinib-d5Inquiry
ACM2098655515Betrixaban-d6Inquiry
ACM1256751117-1Boceprevir-d9Inquiry
ACM2498658254CDK2-IN-14-d3Inquiry
ACM544686206Celecoxib-d4Inquiry
ACM1801709410Daclatasvir-d6Inquiry
ACM1132093709-1Dasatinib-d8Inquiry
ACM2095569767-1Enasidenib-d6Inquiry
ACM1246819500-1Febuxostat-d9Inquiry
ACM1189940962Fenbufen-d9Inquiry
ACM187960083-4Genistein-d4Inquiry
ACM1553977175-1Ibrutinib-d5Inquiry
ACM1217706961Ketoconazole-d8Inquiry
ACM1219805294-3Ketoprofen-d4Inquiry
ACM2050041126Ledipasvir-d6Inquiry
ACM1207560073Sorafenib-d4Inquiry
ACM1257051061Venetoclax-d8Inquiry

Carbon-13 Labeling

  • Common Label: 13C
  • Characteristics & Applications: Chemically identical to 12C with minimal kinetic effect. Ideal for precise metabolic flux tracing and quantitative LC-MS/MS analysis.

Recommended Products:

CatalogNamePrice
ACM2132405571Acetaminophen-13C6Inquiry
ACM1325559203-1Closantel-13C6Inquiry
ACM1261393718-2Diclofenac-13C6Inquiry
ACM1211107684Erlotinib-13C6Inquiry
ACM1185049095-1Flumequine-13C3Inquiry
ACM1216459549-1Ibuprofen-13C6Inquiry
ACM1325559190-1Mefenamic acid-13C6Inquiry
ACM2687960025-1SAH-13C10Inquiry
ACM2300178703Toxoflavin-13C4Inquiry
ACM1261394620-1Efavirenz-13C6Inquiry
ACMA00064150Sacubitril-13C4 hemicalcium saltInquiry

Nitrogen-15 Labeling

  • Common Label: 15N
  • Applications: Used in protein/peptide inhibitor studies, NMR spectroscopy, and tracking nitrogen-containing functional groups.

Recommended Products:

CatalogNamePrice
ACM1216796187Amiloride-15N3 hydrochlorideInquiry
ACMA00063998Liproxstatin-1-15NInquiry
ACM287484371-1DL-Histidine-15NInquiry
ACM287476168-2TPABr-15NInquiry
ACMA00063773Adenosine monophosphate-15N5 dilithiumInquiry

Dual/Multi-Labeling

  • Common Label: 13C & 15N, 13C & D, or 15N & D.
  • Characteristics & Applications: Provides multiple mass tags for enhanced detection specificity and simultaneous tracking of different parts of the molecule. Ideal for complex metabolic studies.

Recommended Products:

CatalogNamePrice
ACM1217820693-1Emtricitabine-13C,15N2Inquiry
ACM244769719-1Hypoxanthine-13C,15N2Inquiry
ACMA000637402-Thiouracil-13C,15N2Inquiry
ACM1044741016-1Vildagliptin-13C5,15NInquiry
ACMA00063850Dabigatran-13C,d3Inquiry
ACMA00064244Encorafenib-13C,d3Inquiry
ACM2748267732Etoricoxib-13C,d3Inquiry
ACM2747917559Flurbiprofen-13C,d3Inquiry
ACM2254100495Osimertinib-13C,d3Inquiry
ACM1261734886Pazopanib-13C,d3Inquiry
ACMA00064127Rapamycin-13C,d3Inquiry
ACMA00064147Ritonavir-13C,d3Inquiry
ACMA00064161Simeprevir-13C,d3Inquiry
ACMA00063808Bictegravir-15N,d2Inquiry
ACM2738376833Cilastatin-15N,d3Inquiry

Representative Inhibitor Classes

Our extensive catalog covers all major inhibitor classes, such as kinase inhibitors, antiviral inhibitors, protease and polymerase inhibitors, NSAIDs and natural product inhibitors. We also provide compounds for cutting-edge research, such as IDH1 Inhibitor 7-d2 for cancer research and ferroptosis inhibitors like Liproxstatin-1-13C6.

Recommended Products:

ClassesCatalogNamePrice
Kinase InhibitorsACMA00063815Brigatinib-13C6Inquiry
ACM1211107684Erlotinib-13C6Inquiry
ACM1228664490-1Gefitinib-d6Inquiry
ACM1092942829-1Imatinib-d8Inquiry
Protease & Enzyme InhibitorsACM1044741016-1Vildagliptin-13C5,15NInquiry
ACM1256751117-1Boceprevir-d9Inquiry
ACM1356355117Saquinavir-d9Inquiry
Epigenetic InhibitorsACM1185237517-1Panobinostat-d4Inquiry
ACMA00063917Entinostat-d4Inquiry
ACM362049658-3Valproic acid-d15Inquiry
Ion Channel & Receptor InhibitorsACM2518100553Tamsulosin-d4 hydrochlorideInquiry
ACM2714485499-1Verapamil-d3 hydrochlorideInquiry
Metabolic & Signaling Pathway InhibitorsACM201612557-32-Deoxy-D-glucose-13CInquiry
ACMA00064127Rapamycin-13C,d3Inquiry
ACM2712126593Trametinib-13C,d3Inquiry
Antivirals & AntibioticsACM1217820693-1Emtricitabine-13C,15N2Inquiry
ACM1261394620-1Efavirenz-13C6Inquiry
ACMA00064147Ritonavir-13C,d3Inquiry
Novel InhibitorsACM2135309510IDH1 Inhibitor 7-d2Inquiry
ACMA00063997Liproxstatin-1-13C6Inquiry

Selection Guide — Concrete, Product-Aware

01

Step 1 — Match the analytical goal

  • Quantitation (LC-MS/MS internal standard): choose 13C or 15N labels where possible (e.g., Diclofenac-13C6, Emtricitabine-13C, 15N2) to avoid chromatographic isotope shifts sometimes seen with deuterium.
  • Tracer/metabolic mapping: prefer multi-site labels (multiple 13C or combined 13C +d) to maximize mass separation (e.g., Rapamycin-13C,d3; Pazopanib-13C,d3).
02

Step 2 — Label placement & metabolic stability

  • For internal standards, place labels at metabolically stable positions (aromatic carbons, non-exchangeable heteroatom positions). Our product list shows many 13C-tagged aromatic or core carbons (e.g., Efavirenz-13C6).
03

Step 3 — Choose isotope type by method

  • LC-MS/MS: 13C or 15N preferred; deuterium acceptable but check coelution. Examples: Vildagliptin-13C5,15N (13C/15N for LC-MS).
  • NMR / mechanistic studies: 13C or 15N (e.g., SAH-13C10 for methylation pathway studies).
04

Step 4— Salt form & physical state

  • If your assay uses a specific salt (sodium, hydrochloride, hemicalcium) or hydrate, request the matching form — the catalog includes many ready salt/hydrate forms (e.g., Pazopanib·HCl, Diclofenac sodium, Niclosamide monohydrate).
05

Step 5 — Scale & purity

  • For method development: mg scale, analytical purity (≥95%) is typical. For extended preclinical studies, request gram-scale custom syntheses — many catalog items are available as custom requests (includes both analytical standards and drug-class lead analogs).
06

Step 6 — Special features to request

  • Click-chemistry handles / clickable labels: some labeled reagents in the list carry functional groups for downstream conjugation (e.g., Linagliptin-13C,d3 noted as a click reagent).

Still unsure how to choose the right isotope-labeled inhibitors?

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Solutions — Integrated Products & Services for Isotope-Labeled Inhibitors

Alfa Chemistry combines catalog isotope-labeled inhibitors with end-to-end technical services to deliver actionable results for drug discovery, ADME/DMPK and mechanistic research.

Custom Stable Isotope-Labeled Compound Synthesis

Metabolism & ADME Research Services

Custom Stable Isotope-Labeled Compound Synthesis

  • Scope: Position-specific labeling, multiple labels, stereospecific labeling when feasible, and scale from mg → gram.
  • Design support: Structural feasibility assessment, recommended labeling sites to minimize isotope loss or kinetic isotope effects, and guidance on salt form and formulation.
  • QC & documentation: HPLC/GC purity, HR-MS, isotopic enrichment analysis, NMR (as appropriate) and batch traceability.

Customizing Stable Isotope-labeled Compounds

Metabolism & ADME Research Services

  • In vitro metabolism: Microsomes, hepatocytes (human/animal), recombinant enzymes for clearance and metabolite identification using isotope-labeled tracers.
  • Metabolite ID & profiling: Use of multi-site or site-specific labeled inhibitors to unambiguously identify metabolic soft-spots, map biotransformations and assign metabolite structures.
  • Stable isotope tracer studies: Pathway mapping, precursor–product tracking, and metabolic flux experiments using custom-labeled inhibitors.
  • PK/ADME support: Assistance integrating labeled internal standards into LC-MS/MS workflows for accurate PK quantitation and metabolite quantification.

Metabolic Research

Case Studies: Leveraging Labeled Inhibitors in Research

Case Study 1 — Preclinical PK Quantitation for an EGFR Inhibitor

Challenge: A CRO needed a robust plasma LC-MS/MS assay for osimertinib with low LLOQ and high reproducibility.

Solution: Alfa Chemistry supplied Osimertinib-d6 (matched deuterated analog) and provided method-enablement.

Results: The matched deuterated standard co-eluted with parent drug, simplified validation, and produced consistent calibration performance across batches—enabling the CRO to complete GLP-style PK runs with reliable quantitation and streamlined data review.

Case Study 2 — Metabolite Mapping of an mTOR Inhibitor (Metabolite ID)

Challenge: A discovery team observed multiple ambiguous LC peaks after hepatocyte incubations of an mTOR inhibitor and needed to unambiguously assign metabolites and metabolic soft-spots.

Solution: Alfa Chemistry supplied Rapamycin-13C,d3 (multi-site labeled tracer) and performed integrated in-vitro incubations plus LC-HRMS analysis to map labeled mass shifts and propose metabolite structures.

Results: Multi-site labeling revealed clear parent→metabolite mass relationships, identified two major oxidative metabolites and one hydrolytic cleavage product, and produced a metabolite map the medicinal chemistry team used to redesign the scaffold for improved metabolic stability.

Case Study 3 — DMPK and NMR Mechanistic Probe for a DPP-4 Inhibitor

Challenge: A pharma team required both accurate PK quantitation and mechanistic NMR evidence of metabolic N-dealkylation for a DPP-4 inhibitor.

Solution: Alfa Chemistry supplied Vildagliptin-13C5,15N (dual 13C/15N labeling) and supported parallel LC-MS quantitation and targeted 15N-NMR experiments to detect labeled fragments.

Results: Dual labeling provided robust LC-MS internal standard performance and enabled direct observation of nitrogen-containing metabolites by 15N-sensitive NMR, giving the project team both quantitative PK data and mechanistic insight to guide next-generation design.

Our Features & Technical Capabilities

The value of an isotope-labeled inhibitor is defined by its chemical and isotopic integrity. Alfa Chemistry adheres to the highest standards to ensure research reliability.

Extensive, Drug-Class-Spanning Catalog

Broad coverage of kinase inhibitors, antivirals, NSAIDs, metabolic inhibitors and natural-product scaffolds

High Isotopic Enrichment

We provide compounds with isotopic enrichment typically >99%, with capabilities for >99.5% for advanced applications. This high purity minimizes spectral interference from unlabeled species in mass spectrometry, ensuring accurate quantification.

Exceptional Chemical Purity

All our inhibitors undergo rigorous purification and quality control. Purity is verified to be >95% by HPLC analysis, a precise and reliable method.

Full QC & Traceability

COA with HPLC/GC purity, HR-MS and isotopic enrichment assay; NMR data provided where applicable to support regulator-ready workflows.

Customer Voices

"Using Alfa Chemistry's 13C-labeled kinase inhibitor was pivotal for our metabolic flux study. The high isotopic purity (>99.5%) gave us clean, interpretable mass spec data with no background interference, allowing us to map the pathway with confidence."

— Dr. Elena Rodriguez,

Principal Investigator, Metabolic Disease Research Institute

"Their custom synthesis of a multi-deuterated BTK inhibitor was delivered on specification. The comprehensive COA included detailed isotopic distribution data, which was exactly what we needed for our pharmacokinetic study submission."

— Mark Chen,

Senior Scientist, Oncology Drug Discovery

FAQs About Isotope-Labeled Inhibitors

Q: Do you supply radiolabeled inhibitors (3H, 14C)?

A: Our primary focus is stable isotope-labeled compounds (2H, 13C, 15N, 18O). Radiolabeled materials require special licensing and handling.

Q: Will the label affect inhibitor potency or binding?

A: Stable isotopes are chemically identical except for mass. In most cases, single-atom substitutions do not change potency. Deuterium can sometimes produce small kinetic isotope effects; discuss labeling location with our technical team to minimize functional perturbation.

Q: What analytical data comes with the compound?

A: COA including MS identity, isotopic enrichment assay, and HPLC/GC purity are standard. NMR data are provided when appropriate or upon request.

Q: Can you do site-specific labeling for stereocenters?

A: Yes — site-specific and stereospecific labeling is available depending on synthetic feasibility. Provide target structure and desired label pattern for assessment.

Q: How should I store my isotope-labeled inhibitor, and what is its shelf life?

A: Most solid inhibitors are stable for 2-3 years when stored dry at -20°C or below. Always refer to the Certificate of Analysis (CoA) for specific instructions. Some may require protection from light or moisture. Prepare stock solutions in appropriate anhydrous solvents (e.g., DMSO) and store aliquots at -80°C for long-term stability.

Q: My inhibitor is not listed in your catalog. Can you synthesize it?

A: Yes. Custom synthesis is a core specialty. We can label existing inhibitor molecules with 2H, 13C, 15N, or 18O at specified positions, with high isotopic enrichment. Contact our custom synthesis team with your structure and requirements.

Q: How do I choose between a 13C -labeled and a deuterated (2H) version of the same inhibitor?

A: For quantitative MS internal standards, both are excellent. 13C -labeled compounds are chemically inert and ideal. For ADME studies exploring metabolic stability, deuterated versions are preferred as the Kinetic Isotope Effect can be studied. Our technical team can advise based on your specific goals.

Related Resources

Check out our latest updates on isotope-labeled inhibitors, from selection guides, technical insights, and cutting-edge research.

Isotope-Labeled Kinase Inhibitors: Precision Analysis in Targeted Therapy

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Isotope-labeled Protease & Enzyme Inhibitors for Bioanalysis

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Whether you need a specific labeled inhibitor synthesized, require a full ADME profile for a candidate molecule, or both, Alfa Chemistry provides a unified, expert resource. Just contact us!

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