Custom peptide synthesis from milligram to multi-gram
Solid-phase and solution synthesis of linear and modified peptides for discovery, assay development and lead optimization. Scale, purity tier and QC depth are matched to how the material will be used—not every program needs the same finishing step.
2–80+
residues (typical range)
mg–100 g
single-lot scale bands
>98%
HPLC purity (top tier)
5–25 d
lead time (indicative)
LC-MS
identity on every lot
What custom synthesis covers
Custom programs specify sequence, counter-ion (acetate, TFA, HCl or formulated salt), purity target and an analytical package aligned to the application. Short catalog-like peptides and long, aggregation-prone sequences both route through Fmoc SPPS or hybrid strategies when a resin cycle is no longer efficient.
Quote and COA carry binding specifications. Ranges on this page describe industry-typical capability bands; difficult motifs may need feasibility before schedule and purity targets are fixed.
Purity tier and typical application
Higher purity usually means additional chromatography and orthogonal analytics. Pick the tier that matches downstream risk.
| Purity band (HPLC area) | Typical use | Indicative finishing |
|---|---|---|
| Crude / desalted | Epitope mapping, quick SAR, in vitro screens tolerant of impurities | Cleavage, ether crash, minimal or no RP-HPLC |
| >80% | Immunization, some enzymatic assays | Single RP-HPLC pass or two passes on difficult sequences |
| >90% | Cell biology, binding assays, animal studies (non-GLP) | RP-HPLC + verified identity; optional residual solvent/TFA |
| >95% | Sensitive bioassays, GLP tox starting material | Multi-pass HPLC; peptide content, water, solvent limits |
| >98% | Reference standard, PK, clinical starting point | Preparative HPLC or ion-exchange; full QC panel as quoted |
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Sequence length and scale (indicative)
Very long or heavily modified sequences may shift to hybrid or fragment condensation with different batch sizes.
Short (≤15 aa)
5 mg–50 g per lot
Higher throughput; multi-mg discovery common
Medium (16–40 aa)
1 mg–10 g per lot
Standard SPPS; purity driver is often aggregation
Long (41–80 aa)
mg–g scale
Lower loading, double couplings, segment ligation may apply
Batch repeat
Same route, tech transfer pack
Method locked after first GMP or qualified research lot
Salt form
TFA, acetate, HCl, others
Salt exchange quoted when counter-ion matters
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Standard vs optional QC
Every lot includes identity. Additional tests are quoted against the purity tier and regulatory path.
| Feature | Analytical test | Research (typical standard) | Higher tier / clinical path |
|---|---|---|---|
| Identity (LC-MS or HRMS) | Yes | Yes | |
| Purity (RP-HPLC) | Yes | Yes | |
| Peptide content (AAA or N) | Optional | Often required | |
| Residual solvents / TFA | On request | Common for >95% material | |
| Water (Karl Fischer) | On request | Common for hygroscopic salts | |
| Endotoxin (LAL) | — | Quoted for animal / device paths | |
| Sterility | — | GMP or formulated supply only |
Gross weight versus net peptide
Suppliers quote and invoice on gross weight: lyophilized peptide plus counter-ions, residual water and salts (commonly TFA or acetate after exchange). Net peptide content—the mass attributable to the amino acid chain—is lower and sequence-dependent.
Amino acid analysis (AAA) or quantitative N-terminal analysis establishes peptide content as a percentage of gross. For dosing studies, convert using the quoted content rather than assuming 100% peptide. Counter-ion choice shifts content: TFA salts often land roughly in the 60–85% peptide content band for typical lengths, while acetate or HCl forms can differ. Exact values are lot-specific on the COA.
Difficult-sequence guidance
Recognizing aggregation, aspartimide and stereochemical risk early saves recycle time.
| Sequence feature | Challenge | Typical mitigation |
|---|---|---|
| Poly-Ala, Val, Ile stretches | Aggregation, incomplete couplings | Lower loading resin, DIC/Oxyma, double coupling, pseudoproline dipeptides |
| Asp–Gly, Asp–Ser | Aspartimide side products | Pseudoproline insertion, piperidine limitation, optimized cleavage |
| N-terminal Pro, C-terminal β-branched | DKP, β-elimination | Pre-formed dipeptides, 2-CTC or Rink strategies, shortened coupling times |
| Multiple Cys | Mis-pairing, oxidation | Orthogonal protection (Trt, Acm, StBu), directed folding after purification |
| Met, Trp | Oxidation in crude | Scavengers in cleavage, minimize air exposure, optional side-chain protection |
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Typical project flow
Define sequence and specification
One-letter code, modifications, purity target, amount (gross or net peptide), salt and required COA tests.
Feasibility and schedule
Difficult motifs reviewed; indicative cycle count and purification strategy before the quote is binding.
Synthesis and cleavage
Fmoc SPPS on polystyrene or PEG-based supports; TFA or tailored cleavage with scavengers matched to sequence.
Purification and QC
RP-HPLC to contracted purity; LC-MS release; optional AAA, solvents and water per the quoted panel.
Ship and document
Lyophilized aliquots or single batch; COA and MSDS; storage at −20 °C or as stated for the salt form.
What you receive
- Lyophilized peptide at stated gross weight and purity
- Certificate of analysis: HPLC, MS, batch ID
- Optional: peptide content, residual TFA/solvents, water
- Sequence confirmation and modification map (if applicable)
- Quote reference for repeat lots at locked specification
Frequently asked questions
State both if net peptide matters for dosing. Default quotes are usually gross lyophilized weight at a purity target. Peptide content is determined on the COA when AAA or equivalent is ordered.
Related
Peptide Modifications
Terminal caps, cyclization, stapling, PTMs, fluorescent and affinity tags, PEG/lipid appendages and unnatural backbones—installed during SPPS or in solution after the chain is built. Each class changes synthesis time, purification and how the product should be specified on the COA.
View detailsPeptide NCE / CMC Development
Process and analytical development that connects research synthesis to a repeatable drug substance story: route selection, impurity fate, specification rationale and stability—structured phase by phase from preclinical supply through commercial readiness.
View detailsAmino Acid Derivatives
Fmoc and Boc protected amino acids, pseudoproline dipeptides, phosphorylated and unnatural derivatives, and pre-activated forms for SPPS. Lot-enantiomeric purity at the monomer propagates into the final peptide—especially on long sequences.
View detailsGMP Peptide API
GMP-manufactured peptide drug substance for clinical trials and commercial demand under a quality system aligned to ICH and regional GMP expectations. Scope is drug substance—synthesis, purification, isolation, release and stability—not discovery-grade custom work.
View detailsReady to specify this for your program?
Share sequence, scale and documentation needs. We reply with indicative specs and a project-specific quotation.