Drug substance (DS) is the direct starting material for drug product manufacturing. ICH Q6B requires DS specifications to cover physicochemical properties, biological activity, and purity/impurities – but requirements vary widely across product types (AAV, mRNA, LV/RV, ADC, radiopharmaceuticals, cell therapies). Common IND deficiencies include missing or incomplete DS release strategies.
Creative Biogene provides a one-stop solution covering eight major product types – from universal release tests (identity, purity, bioactivity, safety) to product-specific CQAs (empty capsid, capping efficiency, RCL/RCR, DAR, radiochemical purity) – with IND/BLA-ready data packages.
| Project Stage | Recommended Package | Key Inclusions |
| Early R&D / Process development | Rapid Release | Simplified validated methods for rapid CQA data to guide process optimization and product development. |
| Pre-IND submission | Advanced Release | Full product-specific CQA testing (AAV empty capsid, rcAAV, titer ratio; mRNA capping efficiency, encapsulation, dsRNA, polyA; LV/RV RCL/RCR, titer, integration; cell therapy viability, phenotyping, RCL, cytotoxicity; ADC DAR, free toxin, unconjugated antibody; fusion/bispecific mispaired species, glycosylation; radiopharmaceutical identity, purity; AOC OAR, payload distribution, free oligo) + IND-ready report format. |
| Commercial / BLA submission | Core Release | Core release tests per ICH Q6B (identity, purity/impurities, biological activity, physicochemical, safety) for commercial batch release and post-marketing stability commitments. |
For Rapid Release: qPCR-based rapid methods (e.g., mycoplasma, sterility screen) are validated in parallel with compendial methods. Final product release for clinical use requires compendial testing where applicable. For specific test panels, method parameters, or pricing, please contact our technical team.
Based on systematic interpretation of ICH Q6B, FDA CGT guidance, relevant USP general chapters, and product-specific guidelines, we structure DS release testing as: product type identification → core testing matrix → specific testing modules → submission-ready data delivery.
ICH Q6B serves as the specification framework, FDA CGT guidance for gene therapy product release, and USP general chapters for method standards. Our facility operates in compliance with GMP principles; data management follows ALCOA+ and 21 CFR Part 11, with full LIMS traceability and independent QA review per batch.
Universal release tests applicable to all biologics:
All methods are validated per ICH Q6B requirements.
For AAV vectors, covering empty capsid rate by orthogonal methods (AUC/IEX/TEM), rcAAV by serial passage with qPCR, and genome/infectious titer ratio, following FDA CGT guidance.
For mRNA vaccines and therapeutics, covering capping efficiency by LC-MS (≥95%), encapsulation efficiency (Ribogreen/DLS), dsRNA residuals (ELISA/J2 antibody), and polyA tail distribution.
For CAR-T, TCR-T, and NK cells, covering viability (Trypan blue), multi-color flow cytometry phenotyping, RCL detection (co-culture with qPCR), and cytotoxicity assays.
For antibody-drug conjugates, covering DAR (HIC-HPLC/LC-MS), free toxin residuals, and the unconjugated antibody ratio.
for Fc fusion proteins and bispecific antibodies, covering mispaired species (LC-MS), glycosylation profiling (LC-MS), and aggregation tendency.
For antibody-oligonucleotide conjugates, covering OAR/DOL, oligonucleotide payload distribution (LC-MS), and free oligonucleotide residuals.
Reports include method validation, raw data, and compliance statements – ready for direct inclusion in the "drug substance release testing" section of CMC documentation.
| Platform | Key Equipment / Capability | Description |
| Chromatography | HPLC/UPLC (SEC, IEX, HIC, RP), LC-MS/MS, CE-SDS, cIEF | Purity (aggregates, charge variants, fragments), identity (peptide mapping), ADC DAR, mRNA capping efficiency and polyA tail |
| Biophysical | AUC, DLS, mass photometry (MP) | AAV empty capsid rate (AUC gold standard), aggregate analysis, particle size, AOC payload distribution (SEC-MALS/AEX-MALS) |
| Molecular Biology | qPCR, ddPCR, NGS | Residual DNA, rcAAV/RCL/RCR, AAV genome titer, lentiviral integration site analysis, mRNA encapsulation efficiency |
| Cell Biology | CO₂ incubators, microplate readers, SPR, flow cytometers | Biological activity/potency (cell-based, ELISA, SPR), cell therapy phenotyping, cytotoxicity, viral titer (TCID50) |
| Microbiology | BSC, incubators, sterility isolator, colony counter | Sterility (USP <71>), mycoplasma (qPCR + culture parallel validation), endotoxin (USP <85> kinetic chromogenic) |
| Physicochemical | pH meter, osmometer, UV/BCA, particle counter | pH, osmolality, concentration, particulates (USP <788>) |
| Radiopharmaceutical | Gamma spectrometer, HPLC-radio, TLC-radio, activity meter | Radionuclide identification, radiochemical purity, radionuclidic purity, radioactivity (USP <823>/<825>) |
Drug substance release testing is not an "option" – it is a mandatory requirement under ICH Q6B for biologics and a clear expectation under FDA CGT guidance for gene therapy products. If you are preparing a DS release plan for your biologic or have uncertainties about product-specific testing, now is the best time to front-load risks and validate proactively.
We will systematically design a dual-engine strategy of core release plus product-specific testing tailored to your product type, development stage, and regulatory pathway – ensuring every decision is supported by robust data, enhancing IND/BLA submission certainty and controllability from the source. Contact us today to request your customized drug substance release testing plan.
Q1: What is the difference between drug substance (DS) release testing and drug product (DP) release testing?
A: DS release testing occurs before formulation and filling, focusing on intrinsic quality attributes – identity, purity, impurities, biological activity, and safety (sterility/mycoplasma/endotoxin). DP release testing adds formulation-specific attributes – particulates, container-closure integrity, fill volume, visible particles, and stability. DS release is a prerequisite for DP release. ICH Q6B primarily addresses DS release, while USP chapters cover DP release requirements.
Q2: Is empty capsid rate testing mandatory for AAV DS release? What is the acceptance criterion?
A: Yes. FDA 2020 CGT guidance explicitly requires empty capsid rate testing. Industry practice typically expects an empty capsid rate <30% (full capsid >70%), but specific criteria should be product- and process-based. Our Advanced package provides orthogonal methods (AUC, IEX, TEM).
Q3: What capping efficiency level should be achieved for mRNA products?
A: Industry typical ≥95% for Cap-1 structure. LC-MS/MS is the most comprehensive method, quantifying Cap-0, Cap-1, Cap-2, and uncapped species. Our Advanced package provides LC-MS capping efficiency with full validation.
Q4: For DS release, should I choose the mycoplasma culture or the qPCR rapid method?
A: USP <63> requires that a qPCR method, if used as a replacement, must be validated to ≤10 CFU/mL and validated in parallel with culture. For an IND submission, we recommend parallel validation. For commercial release, a fully validated qPCR method may replace culture with regulatory approval. Our Advanced package provides parallel validation.
Q5: For ADC DAR determination, should I choose HIC-, HPLC, or LC-MS?
A: HIC-HPLC is suitable for routine release testing (high throughput, low cost). LC-MS offers higher resolution and deeper characterization (payload distribution, impurities). Our Advanced package offers both HIC-and HPLC for release, and LC-MS for characterization.
Q6: How does DS release for AOCs differ from traditional ADCs?
A: AOCs conjugate oligonucleotides (siRNA, ASO) rather than small molecule toxins. Key CQAs include OAR (analogous to DAR), payload distribution, free oligonucleotide residuals, and sequence integrity. Testing strategies follow the ADC framework of ICH Q6B, adapted for oligonucleotide characteristics. Our Advanced package provides AOC-specific methods (SEC-MALS, AEX-MALS, LC-MS).
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