Peptide-drug conjugates (PDCs)
Tumor-homing peptides conjugated to cytotoxic or targeted payloads through cleavable or stable linkers. We synthesize and characterize peptide vectors, payloads, and assembled PDCs with potency-appropriate containment.
3-part
vector-linker-payload
RGD / NGR
motif families
Cathepsin
cleavable linkers
LC-MS
DAR / integrity
Why peptide conjugates
Peptide-drug conjugates occupy a middle ground between small-molecule ADC linkers and large biologic carriers: they can penetrate some solid-tumor niches, present defined receptor or protease biology, and are manufactured with peptide synthesis expertise plus small-molecule payload handling.
Programs succeed when tumor homing, linker stability in plasma, and payload release in the tumor microenvironment are co-optimized—not when any single component is optimized in isolation.
PDC architecture
Three compositional zones define manufacturability, stability, and regulatory characterization.
- 01
Homing peptide
PDC synthesis: homing peptides, cleavable linkers, and cytotoxic payloads with HPAPI-aware conjugation analytics.
- 02
Linker
Cleavable (protease-sensitive dipeptides, disulfides) or non-cleavable (PEG, alkyl) tethers that set plasma stability and payload release mechanism. Linker choice drives impurity taxonomy and DAR equivalents for peptide conjugates.
- 03
Payload
Cytotoxic warhead, tubulin inhibitor, or molecularly targeted agent. Potent payloads trigger HPAPI containment and occupational banding identical to small-molecule HPAPI practice.
Manufacturing sequence
Peptide synthesis and cyclization
SPPS with on-resin or in-solution cyclization; receptor-binding validation is client-led.
Linker-payload intermediate
Payload activated with linker in contained suite when banding requires; intermediates release with stringent identity tests.
Conjugate assembly
Site-specific (e.g., Cys maleimide, oxime) or statistical conjugation; purification to agreed composite purity.
Release and stability
LC-MS profile, hydrolysis monitors, and storage guidance for conjugate integrity.
Indicative conjugate analytics
Identity
LC-MS (intact and fragments)
Payload retention critical
Purity
HPLC / SEC
Method per construct
Loading
Drug-to-peptide ratio equivalent
For multi-payload designs
Residual solvents
ICH Q3C
Peptide and small-molecule panels
Endotoxin
LAL when injectable path
Per client spec
Figures are indicative industry-typical values. Lot- and project-specific data appear on the quotation and certificate of analysis.
Frequently asked questions
We manufacture client-designed sequences. Sequence selection and target validation remain sponsor activities unless contracted separately.
Related
Radioligand Precursors
Chelator-conjugated peptides and small-molecule ligands prepared for radiolabeling with therapeutic or diagnostic isotopes. DOTA, NOTA, and NODAGA handles with GMP-minded analytics support theranostic oncology programs.
View detailsPeptide 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 detailsCustom Peptide Synthesis
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.
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.