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Drug Conjugation Services

Antibody–drug, peptide–drug, protein–drug, and oligo–drug conjugates with optimized linkers and oncology payloads — engineered with full analytics and documentation by Bio-Synthesis.

Speak to a Scientist Overview ADC Services
ADC, PDC & Protein–Drug
Oncology Payload Libraries
45+ Years of Bioconjugation
Texas, USA
Overview Drug Payload Classes Antibody–Drug Conjugates Oligo–Drug Conjugates Peptide–Drug Conjugates Protein–Drug Conjugates

oligo bioconjugation Overview

Bio-Synthesis designs and produces high-performance drug conjugates that link antibodies, peptides, proteins, and oligonucleotides to small-molecule and cytotoxic payloads. Our platform supports ADCs, peptide–drug conjugates (PDCs), protein–drug conjugates, and oligo–drug formats for oncology, immunology, and targeted delivery applications.

We provide end-to-end drug conjugation services — from carrier and linker strategy through conjugation, purification, analytics, and documentation — supporting both discovery and OEM/kit applications. The platform is optimized for controlled drug loading, minimal aggregation, and lot-to-lot reproducibility.

Biomolecule Carrier
Antibody · Peptide · Protein · Oligo
Linker & Conjugation
NHS · Maleimide · Click · Enzymatic
Drug Payload
Cytotoxic · Small Molecule · Label
Therapeutic Conjugates

Antibody–drug, peptide–drug, protein–drug, and oligo–drug designs for targeted delivery, oncology, and immune modulation.

Diagnostic & Imaging

Drug–antibody and drug–peptide conjugates with fluorophores, chelators, or reporter tags for in vitro and in vivo imaging.

Documentation & Scale

Method summaries, CoAs, and optional tech transfer packages to support preclinical, kit, and OEM programs.

Core Drug Conjugation Service Categories
  • Antibody–Drug Conjugates (ADCs) using cysteine, lysine, and site-selective chemistries.
  • Peptide–Drug Conjugates (PDCs) including CPPs, tumor-homing, and receptor-targeting peptides.
  • Protein–Drug Conjugates with enzymes, nanobodies, carrier proteins, and receptors.
  • Oligo–Drug Conjugates including aptamer–drug, siRNA–drug, and ASO–drug formats.
  • Oncology Payload Libraries (taxanes, anthracyclines, alkylating agents, etc.).
  • Imaging & Labeling Payloads (fluorophores, chelators, biotin, click handles).
  • Immune Modulators and small-molecule inhibitors as conjugated payloads.
  • Custom Linker Architectures (cleavable, non-cleavable, spacer/PEG, click-ready).

Drug conjugation services can be combined with carrier delivery platforms (ADC & LNP) and broader bioconjugation services from Bio-Synthesis.

Representative Drug Payload Classes

Expand a payload class to view representative examples, payload type, typical function, and conjugation notes. Feasibility is project-dependent and driven by functional groups, stability, and the desired mechanism (stable vs cleavable).

cancer drug conjugation peptide drug conjugates oncology payloads
Representative payloads Drug type Typical function Conjugation notes
Anthracyclines: Doxorubicin, Epirubicin, Daunorubicin, Idarubicin, Elsamicin A DNA-intercalators Cytotoxic payloads for targeted delivery constructs Linker selection often driven by release vs stability; manage redox-/pH-sensitivity where relevant.
DNA-binding / antibiotic antitumor agents: Actinomycin D, Bleomycin, Mithramycin, Mitomycin Antitumor antibiotics Mechanistic tools and cytotoxic payload exploration Avoid harsh conditions; evaluate oxidative and hydrolytic stability during route selection.
Taxanes: Taxol (Paclitaxel), Docetaxel, Tesetaxel Microtubule agents Hydrophobic oncology payloads for PDC research Hydrophobicity impacts purification/solubility; spacers (e.g., PEG) may improve handling.
Vinca alkaloids: Vincristine, Vinblastine, Navelbine (Vinorelbine) Microtubule agents Cytotoxic payloads for ADC/PDC exploration Prefer site-defined handles to control stoichiometry and reduce heterogeneity.
Topoisomerase agents: Etoposide (VP-16), Irinotecan, Topotecan Topo inhibitors DNA/topo-targeting payloads Assess stability and reactive handles; define acceptance criteria for loading and purity.
Platinum drugs: Cisplatin, Carboplatin DNA crosslinkers DNA-damaging payload class Coordination chemistry can affect route choice; evaluate compatibility with buffers and carrier residues.
Alkylators / mustards / nitrosoureas: Busulfan, Nitrogen mustards, Uramustine, Chloroambucil, Melphalan, Cyclophosphamide, Ifosfamide, Carmustine, Lomustine, Semustine, Procarbazine, Dacarbazine Alkylating agents Release-mechanism and stability studies in drug–peptide conjugates Project-specific feasibility; payload stability and available functional groups guide coupling strategy.
Antimetabolites / nucleoside analogs: Methotrexate, Pemetrexed, Mercaptopurine, Thioguanine, Ara-C (Cytarabine), Gemcitabine, Capecitabine, Tegafur–uracil, Nelarabine, Fludarabine, Leustatin (Cladribine), Hydroxyurea Antimetabolites Drug–peptide conjugates and peptide–small molecule hybrids Route selected to preserve labile motifs; handle planning prevents multi-site labeling.
Targeted small-molecule inhibitors: Erlotinib, Lapatinib Kinase inhibitors Target engagement and delivery constructs Conjugation site chosen to maintain pharmacophore exposure; spacer length often optimized.
Other / project-dependent: Mitoxantrone, Praziquantel, Lamivudine, Ambroxol, Demecolcine, CCP (3-cyano-2-chloropyridine) Mixed Proof-of-concept payloads and assay tools Feasibility evaluated from structure/functional groups; recommend a handle + linker plan aligned to readout.
Biologics (typically carriers or protein conjugates): Bevacizumab (Avastin), Rituximab, Tumor necrosis factor (TNF) Proteins / antibodies Usually used as targeting carriers rather than “payloads” If your project involves antibody/protein conjugation, we can support site-selective protein/peptide coupling workflows (project-dependent).

peptide–antibiotic conjugates antibiotic conjugation antibiotic peptide conjugate
Representative payloads Drug type Typical function Conjugation notes
Amoxicillin, Ampicillin, Tetracycline β-lactams / tetracyclines Targeted antimicrobial delivery, uptake studies Amine and carboxyl handles commonly used; preserve β-lactam ring integrity.
Streptomycin, Gentamicin Aminoglycosides Cell entry and mechanistic probes Highly polar and polycationic; purification strategy adjusted accordingly.
Chloramphenicol, Du-6859a Broad-spectrum antibiotics Model conjugates and assay tools Avoid harsh conditions to maintain aromatic nitro stability.
Sulfonamide family: Sulfamethazine, Sulfadiazine, Sulfafurazole, Sulfamethoxazole, Sulfamethoxypyridazine, Sulfamonomethoxine, Sulformetoxine, Sulfaguanidine, Sulfathiodiazole, Sulphamethoxydiazine, Sulfaquinoxaline, Madribon Sulfonamides Class-wide antimicrobial targeting Primary amine and sulfonyl groups enable site-defined conjugation.
Clenbuterol, Ractopamine, Salbutamol β-agonists Detection, enrichment, and immunoassay standards Frequently conjugated to peptides or proteins for ELISA and capture reagents.

vitamin conjugation biotin conjugation assay & capture
Representative payloads Drug type Typical function Conjugation notes
Vitamin E (α-, β-, γ-, δ-tocopherols; tocotrienols) Hydrophobic vitamins Membrane interaction, antioxidant biology, delivery studies Core Bio-Synthesis strength. Spacer-assisted conjugation (PEG or alkyl linkers) is routinely used to manage extreme hydrophobicity and preserve peptide solubility.
Vitamin A (retinoids), Vitamin D (calciferols), Vitamin K (phylloquinone/menaquinone) Fat-soluble vitamins Targeting, uptake, and mechanistic probes Typically conjugated via spacer/linker architectures to reduce aggregation and steric interference.
Vitamin B-complex: B1 (thiamine), B2 (riboflavin), B6 (pyridoxine), B12 (cobalamin) Water-soluble vitamins Receptor-mediated uptake, transport, and assay workflows Vitamin B12 conjugation uses defined peripheral handles to preserve intrinsic binding motifs.
Vitamin C (ascorbic acid) Redox-active vitamin Stability and antioxidant mechanism studies Oxidation sensitivity considered during route selection and purification.
Biotin (vitamin B7), Folate (vitamin B9) Affinity / targeting handles Avidin/streptavidin capture, receptor targeting, immobilization Widely used across antibody, peptide, protein, and oligonucleotide conjugates with controlled stoichiometry.

aspirin conjugates azacytindine memantine
Prepresentative payloads Drug type Typical function Conjugation notes
Aspirin, Ibuprofen, Ketoprofen NSAIDs Model small molecules for conjugation workflows Often coupled via amide/activated ester routes depending on handle availability.
5‑Azacytidine Nucleoside analog Proof-of-concept conjugation and stability studies Stability considerations drive route selection and purification conditions.
Lisinopril, Pravastatin Small-molecule drugs Delivery/mechanism studies Handle planning prevents multi-site labeling; QC aligned to intended use.
Memantine HCl, Propranolol CNS / cardio drugs Model payloads for drug–peptide conjugates Ionizable groups can affect HPLC behavior; method selection adjusted accordingly.

Not listed? Send structure or catalog number + desired attachment site/chemistry—our team will recommend a practical route.

Safety & Handling
  • Oncology payloads require appropriate safety and handling procedures.
  • Provide safety data sheets and handling guidelines when shipping payloads.
  • Bio-Synthesis follows internal safety controls for high-potency compounds.
Compatibility & Analytics
  • Match payload solubility and reactivity with chosen linker chemistry.
  • Confirm drug loading and integrity via LC-MS, HPLC, and UV/Vis where applicable.
  • Define analytical acceptance criteria for each conjugate type.

Antibody–Drug Conjugates (ADC)

Antibody–Drug Conjugates (ADCs) combine monoclonal antibodies with potent cytotoxic or functional small-molecule payloads. Bio-Synthesis develops custom ADCs using cysteine, lysine, and site-directed conjugation strategies, optimizing linker choice, DAR, and aggregation for oncology and targeted delivery applications.

Antibody Carrier
mAb · Fab · scFv · Bispecific
Linker Chemistry
Maleimide · NHS · Click · Cleavable
Drug Payload
Cytotoxic · Inhibitor · Label
Product Highlights
  • Cysteine (maleimide), lysine (NHS ester), and click-compatible ADC chemistries.
  • Control of DAR and aggregation with process and buffer optimization.
  • Cleavable linkers (Val-Cit, disulfide, acid-labile) and stable non-cleavable linkers.
  • Anthracycline, taxane, alkylator, and other oncology payload options.
Preferred Applications
  • Exploratory ADC panels for target and payload evaluation.
  • Comparator constructs (DAR series, linker variants, payload families).
  • ADC-like antibody–label conjugates for imaging and biodistribution studies.
  • Preclinical and kit/OEM ADC reagent production.

Conjugation Strategy
  • Align antibody format (IgG, Fab, scFv) with preferred conjugation site (lysine vs cysteine).
  • Use partial reduction of interchain disulfides for controlled cysteine exposure.
  • Optimize spacer length and hydrophilicity to limit aggregation and maintain binding.
  • Confirm DAR and species distribution by intact LC-MS and SEC-HPLC.
Formulation & Stability
  • Choose buffer systems compatible with both antibody and payload stability.
  • Assess freeze–thaw and temperature stability for storage and shipment.
  • Evaluate binding, potency, and off-target signals versus unconjugated antibody.
  • Define specifications for DAR window, aggregation limit, and purity.
Antibody-drug conjugate LC-MS analysis comparing IgG control and ADC DAR 3.2 under Bio-Synthesis conjugation
LC-MS analysis of an Antibody–Drug Conjugate (ADC) showing the molecular weight shift from IgG control (144,654 Da) to conjugated ADC (149,114 Da; DAR ≈ 3.2). Demonstrates precise payload loading and QC verification by Bio-Synthesis.

Oligonucleotide–Drug Conjugates (ODC)

Oligonucleotide–Drug Conjugates (ODCs) combine siRNA, ASO, DNA/RNA, or aptamers with small-molecule payloads for targeted delivery, controlled activation, or dual-modality therapeutics. Bio-Synthesis supports aptamer–drug conjugates, siRNA–drug constructs, and other oligo–drug architectures.

Oligonucleotide Carrier
siRNA · ASO · DNA/RNA · Aptamer
Conjugation Chemistry
Click · Amide · Cleavable
Drug Payload
Cytotoxic · Inhibitor · Probe
Product Highlights
  • Aptamer–drug conjugates (ApDCs) for receptor-targeted delivery.
  • siRNA–drug and ASO–drug constructs with cleavable linkers.
  • Oligo–label and oligo–inhibitor constructs for imaging and mechanistic work.
  • Integration with ligand or lipid conjugates when desired.
Preferred Applications
  • Dual-modality oligo–drug therapeutics and theranostics.
  • Aptamer-guided cytotoxic or inhibitor delivery.
  • Target engagement and mechanistic probes for oligo targets.
  • Assay-ready oligo–drug standards for method development.

Oligo & Site Selection
  • Select 5′ or 3′ modification positions compatible with oligo function.
  • Maintain aptamer folding and binding motifs when adding payloads.
  • Confirm oligo integrity and conjugation level by LC-MS and HPLC.
Payload & Linker
  • Use cleavable linkers when drug function requires intracellular release.
  • Consider hydrophilic spacers for hydrophobic payloads to reduce aggregation.
  • Align linker and payload chemistry with in vivo or in vitro application.
Taxol-siRNA Conjugates
  • Conjugated MW: 8396.55
  • MALDI-TOF MS: 8397.14
  • Targeting Purity: >90%
Taxol Oligo Conjugation
Figure 1. Conjugation of Taxol to 5' end of Aptamer

Peptide–Drug Conjugates (PDC)

Peptide–Drug Conjugates use targeting, cell-penetrating, or tumor-homing peptides to deliver small-molecule payloads to specific cells or tissues. Bio-Synthesis constructs PDCs with optimized linkers and spacers to balance potency, selectivity, and stability.

Peptide Carrier
CPP · Tumor-Homing · Receptor Ligand
Linker Chemistry
Amide · Click · Cleavable
Drug Payload
Cytotoxic · Inhibitor · Probe
Product Highlights
  • CPPs, tumor-targeting, and receptor-binding peptides conjugated to drugs.
  • Single or multi-drug loading via orthogonal handles.
  • Cleavable linkers for intracellular release vs non-cleavable linkers for stable display.
  • PDCs with taxanes, anthracyclines, alkylators, and targeted inhibitors.
Preferred Applications
  • Peptide-guided cytotoxic delivery to tumors or diseased tissues.
  • Cell-penetrating peptide–drug constructs for intracellular targets.
  • Peptide–drug tools for receptor occupancy and trafficking studies.
  • In vitro and in vivo SAR campaigns on peptide, linker, and payload.

Peptide & Linker Design
  • Position conjugation site away from key binding motifs or helices.
  • Use PEG or flexible linkers to reduce steric hindrance and aggregation.
  • Evaluate peptide length, charge, and hydrophobicity for PK and tissue distribution.
Payload & Release
  • Match linker cleavage mechanism (enzymatic, pH, redox) to target biology.
  • Confirm drug:peptide stoichiometry and purity by LC-MS/HPLC.
  • Correlation of in vitro uptake/release with in vivo behavior where possible.
Case Study for Peptide Drug Conjugation
Drug Peptide Bioconjugation
Figure 1. Peptide-(PEG)4-ethylenediamine Bioconjugation

Protein–Drug Conjugates

Protein–Drug Conjugates extend beyond antibodies to enzymes, receptor ectodomains, carrier proteins, and nanobodies. Bio-Synthesis develops protein–drug constructs that preserve biological function while delivering potent small molecules or reporters.

Protein Carrier
Enzyme · Receptor · Nanobody
Conjugation Chemistry
NHS · Maleimide · Click
Drug Payload
Cytotoxic · Inhibitor · Label
Product Highlights
  • Nanobody–drug and enzyme–drug conjugates tailored to your targets.
  • Stable thioether and amide linkages for in vivo durability.
  • Custom spacer/PEG to tune solubility and reduce aggregation.
  • Functional activity checks for both protein and payload components.
Preferred Applications
  • Receptor-specific protein–drug delivery systems.
  • Enzyme–drug constructs for prodrug activation and local release.
  • Protein–label conjugates for imaging, tracking, and biodistribution.
  • Multivalent constructs combining multiple proteins or payloads.

Protein Engineering
  • Assess available lysine/cysteine sites or introduce defined handles if needed.
  • Preserve catalytic or binding sites by strategic conjugation location.
  • Use buffer and pH conditions that maintain protein structure through conjugation.
QC & Function
  • Verify protein integrity by SDS-PAGE and intact MS.
  • Measure activity or binding before and after conjugation.
  • Monitor aggregation, charge variants, and conjugation distribution.

Technical Summary — Drug Conjugation Platform

Workflow
  • Project intake (carrier, payload, biology, and risk assessment).
  • Linker and conjugation route selection and optimization.
  • Conjugation with in-process monitoring for DAR and aggregation.
  • Purification tailored to conjugate type (chromatography, filtration, etc.).
  • QC and documentation aligned with downstream needs.
Controls & Comparators
  • Unconjugated carrier and payload as baseline controls.
  • Linker and DAR variants for SAR and optimization studies.
  • Cleavable vs non-cleavable linker comparisons.
  • Functional benchmarks (potency, binding, imaging, PK).
Analytics & Documentation
  • Identity and purity by LC-MS and HPLC/UPLC.
  • Aggregation by SEC-HPLC; DAR/drug loading by MS and UV.
  • Functional assays where applicable (binding, activity, potency).
  • Certificates of Analysis and optional tech transfer packages.

FAQ

Which carrier types do you support for drug conjugation?

We work with antibodies, Fabs, nanobodies, peptides, proteins, enzymes, and oligonucleotides, including both standard and custom formats with appropriate conjugation handles.

Can you provide both the carrier and the drug payload?

In many cases we can source or synthesize carriers and certain payloads; in other cases, clients supply proprietary antibodies, peptides, proteins, or drugs. We will clarify material responsibilities during scoping.

Do you support OEM or diagnostic kit reagent projects?

Yes. We support projects that require enhanced documentation, lot statistics, and stability data suitable for diagnostic kits and OEM applications.

What information do you need to scope a drug conjugation project?

At minimum, we need the carrier identity, payload, desired conjugation type, intended application, and key performance metrics (e.g., potency, binding, imaging, PK) you plan to evaluate.

More FAQ'sAll FAQ's
Contact

Speak to an Oligo Bioconjugation Scientist

Share your oligo sequence format, carrier, application, and target performance. We will recommend a conjugation route, linker strategy, and QC package, then provide a project quote.

Request a Quote Feasibility Review OEM / Kit Partner Sample Submission
Email: sales@biosyn.com
Phone: +1-972-420-8505
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Recommended Reading & Bio-Synthesis Resources

  1. Chari, R. “Antibody–Drug Conjugates: An Emerging Concept in Targeted Cancer Therapy.” *Cancer Research*.
  2. Srinivasarao, M. & Low, P. “Ligand-Targeted Drug Delivery.” *Chemical Reviews*.
  3. Bargh, J. “Linker Design Considerations for ADCs.” *MedChemComm*.
  4. Beck, A. “Strategies and Challenges for Next-Generation ADCs.” *Nature Reviews Drug Discovery*.
  5. Krall, N. “Protein–Drug Conjugates for Targeted Therapeutics.” *Angewandte Chemie*.
  6. Williford, J. “Oligonucleotide Conjugates for Precision Drug Delivery.” *Accounts of Chemical Research*.

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