Icotrokinra Oral Peptide Drug Amino Acid Derivatives H-Sar-NH2. HCL CAS NO. 5325-64-4

Icotrokinra (JNJ-77242113) is an oral IL-23 receptor antagonist peptide. Compared with traditional injectable peptides, oral peptide drugs require additional structural optimization to improve gastrointestinal stability, enzymatic resistance, and absorption properties. N-methyl amino acid derivatives such as Sarcosine are commonly introduced into peptide structures because they can improve peptide drug-like characteristics.

The introduction of N-methyl groups can reduce hydrogen bonding interactions between peptide bonds and proteases, decrease enzymatic recognition, and improve resistance to metabolic degradation. After incorporation into peptide structures, the N-methylated peptide bond (–CO–N(CH₃)–) provides higher stability compared with conventional peptide bonds (–CO–NH–).

In addition, N-methylation can regulate peptide backbone flexibility, influence molecular conformation, and help maintain the active structure required for receptor binding. These properties are particularly important for oral peptide therapeutics, where maintaining biological activity while improving stability is a key challenge.

Unlike Fmoc-Sar-OH, which is directly used in Fmoc-SPPS as an amino acid coupling building block, H-Sar-NH₂·HCl is generally used as an N-methylated amide fragment or terminal modification reagent. It can participate in fragment condensation or liquid-phase peptide synthesis to introduce a Sar-NH₂ moiety into the peptide structure.

A typical application can be described as:

Peptide-COOH + H-Sar-NH₂·HCl → Peptide-Sar-NH₂ fragment

This strategy can be useful for the synthesis of complex peptides containing N-methyl amino acid motifs, especially in oral peptide and macrocyclic peptide development.

Compared with conventional amino acid derivatives, H-Sar-NH₂·HCl requires higher control during synthesis and purification. Key challenges include controlling N-demethylated impurities, removing residual inorganic salts, controlling moisture content, and ensuring batch-to-batch consistency. Typical quality requirements include HPLC purity, assay, water content, residual solvents, and impurity profile control.