Linaclotide: Peptide Profile, CAS & Properties
CAS 851199-59-2 · 1526.74 g/mol
Linaclotide (CAS 851199-59-2) is a 14-amino-acid guanylate cyclase-C (GC-C) agonist peptide, cyclised by three intramolecular disulfide bridges, with molecular formula C59H79N15O21S6 (~1526.74 g/mol). It is approved by the US FDA and EMA for IBS-C and chronic idiopathic constipation. This page provides reference information on Linaclotide.
- CAS Number
- 851199-59-2
- Molecular Formula
- C59H79N15O21S6
- Molecular Weight
- 1526.74 g/mol
- Drug Class
- guanylate cyclase-C (GC-C) agonist
What is Linaclotide?
Linaclotide is an orally administered, minimally absorbed 14-amino-acid synthetic peptide agonist of guanylate cyclase-C (GC-C). Its sequence (Cys-Cys-Glu-Tyr-Cys-Cys-Asn-Pro-Ala-Cys-Thr-Gly-Cys-Tyr) is constrained by three intramolecular disulfide bridges, a folding pattern that is essential to its activity and the central synthesis challenge of the molecule. It acts locally on the luminal surface of the intestinal epithelium: binding to transmembrane GC-C receptors elevates intracellular and extracellular cyclic GMP (cGMP), which stimulates chloride and bicarbonate secretion (largely via CFTR), increasing intestinal fluid and accelerating transit.
As an active pharmaceutical ingredient, linaclotide (CAS 851199-59-2, molecular formula C59H79N15O21S6, ~1526.74 g/mol) is typically presented as a lyophilised powder for formulation into oral solid finished dosage forms. It is approved by the US FDA and the EMA for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation.
How Linaclotide Is Produced & Characterised
Linaclotide is a synthetically demanding peptide: six cysteine residues must form three specific disulfide bonds (1-6, 2-10, 5-13), and incorrect pairing produces inactive disulfide isomers that are difficult to separate. In industry, the molecule is generally prepared by Fmoc solid-phase peptide synthesis (SPPS), followed by a controlled oxidative folding step that drives formation of the correct three-disulfide topology, then purification on preparative dynamic axial compression (DAC) HPLC columns to resolve the target from misfolded and deletion-sequence impurities.
Characterisation typically combines UPLC/HPLC for purity, LC-MS for sequence and disulfide-connectivity confirmation, and assessment of minor structural variants such as disulfide-scrambled isomers. Lyophilisation yields a stable, uniform powder. This section describes the general production and analytical approach for this peptide class as reference information.
Typical Quality Specifications & Impurity Control
Pharmaceutical-grade linaclotide is generally released against a defined specification with a Certificate of Analysis. Purity is commonly determined by UPLC/HPLC, while sequence, disulfide connectivity and minor structural variants are confirmed by LC-MS impurity profiling. Typical release purity is around ≥99.0%, with individual impurities — including disulfide-scrambled isomers — controlled below 0.10%, supported by ICH Q1A(R2) long-term and accelerated stability data.
Analytical methods are typically validated to ICH Q2(R1), and water content, counter-ion content, residual solvents and peptide content are characterised. These figures are presented as representative reference values for the molecule, not as an offer of supply.
Regulatory Status & Reference Context
Linaclotide is an approved active ingredient. It was first approved by the US FDA in 2012 and is also approved by the EMA for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation. As a regulated API, it is normally handled within established CMC frameworks — for example US-DMF Type II dossiers and CTD Module 3 documentation — when used in finished-product submissions such as IND/NDA/ANDA filings.
This page is intended as a scientific and regulatory reference for the molecule. It does not constitute medical advice, dosing guidance, or an offer to supply linaclotide. WinHyCare's own API supply offering is limited to Semaglutide.
Linaclotide API — Specifications
| Compound | Linaclotide |
|---|---|
| CAS Number | 851199-59-2 |
| Molecular Formula | C59H79N15O21S6 |
| Molecular Weight | 1526.74 g/mol |
| Sequence | 14 amino acids, three disulfide bridges (1-6, 2-10, 5-13) |
| Drug Class | Guanylate cyclase-C (GC-C) agonist |
| Appearance | White to off-white lyophilised powder |
| Typical Purity (HPLC) | ≥ 99.0% (single impurity < 0.10%) |
| Synthesis Route | Fmoc SPPS + controlled oxidative folding + DAC prep-HPLC |
| Regulatory Status | FDA-approved (2012) and EMA-approved for IBS-C & chronic idiopathic constipation |
| Form | Lyophilised powder |
| Storage | Store at -20°C, protected from light & moisture |
Reference data only — WinHyCare neither supplies nor manufactures this compound; see our Semaglutide API for the product we supply. Regulatory status: Approved as an active ingredient by major regulators including the US FDA (first approved 2012) and the EMA for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation.
Linaclotide API — Frequently Asked Questions
What is Linaclotide?
Linaclotide is a synthetic, minimally absorbed 14-amino-acid peptide that acts as an agonist of guanylate cyclase-C (GC-C) on the intestinal epithelium. Binding to GC-C raises cyclic GMP, stimulating chloride and bicarbonate secretion and increasing intestinal fluid and transit. It is cyclised by three intramolecular disulfide bridges.
What is the CAS number and molecular weight of Linaclotide?
Linaclotide's CAS number is 851199-59-2, its molecular formula is C59H79N15O21S6, and its molecular weight is approximately 1526.74 g/mol.
Is Linaclotide an approved active ingredient?
Yes. Linaclotide is approved as an active ingredient by major regulators including the US FDA (first approved in 2012) and the EMA for irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation.
What class of peptide is Linaclotide?
Linaclotide is a guanylate cyclase-C (GC-C) agonist. It is a 14-amino-acid disulfide-rich peptide whose activity depends on three specific intramolecular disulfide bonds (1-6, 2-10, 5-13).
What is Linaclotide used for?
Linaclotide is approved for the treatment of irritable bowel syndrome with constipation (IBS-C) and chronic idiopathic constipation. This is general reference information and not medical advice.
How is the correct disulfide folding of Linaclotide achieved?
Linaclotide requires three specific disulfide bonds (1-6, 2-10, 5-13). It is generally produced by Fmoc SPPS followed by a controlled oxidative folding step to drive the correct topology, then DAC preparative HPLC to resolve the target peptide from misfolded isomers and deletion sequences, with LC-MS used to confirm connectivity.
Related Peptide APIs
Teduglutide API
CAS 197922-42-2
GLP-1 & Incretin Multi-AgonistsSemaglutide API
CAS 910463-68-2
GLP-1 & Incretin Multi-AgonistsTirzepatide API
CAS 2023788-19-2
Growth & MetabolismSermorelin API
CAS 86168-78-7
Technical Reference Page
WinHyCare neither supplies nor manufactures Linaclotide; this page is provided as a technical reference. The peptide API we supply is Semaglutide.