Antibody Fragment Development

As part of our layered pathway spanning Pharmaceutical Development & Manufacturing → Drug Substance Development → Monoclonal Antibody Development, we deliver focused antibody fragment development services. We concentrate on establishing robust, phase-appropriate CMC foundations for fragment-based biotherapeutic modalities.

Designability & Reformatting Service

We evaluate input sequences for chemical and structural liabilities (deamidation, isomerization, oxidation motifs, glycine clipping, PTM hotspots), surface hydrophobicity, net charge distribution, and aggregation-prone regions. We then reformat binding domains into fragment architectures (Fab, scFv, VHH, VH/VL) with rational linkers, signal peptides, and secretion tags. Where useful, we test alternative framework backbones to improve expression and colloidal stability while preserving binding epitopes.

Prototype Expression Service

We establish bench-scale expression prototypes matched to the fragment class. For Fab and F(ab')₂, we typically explore mammalian secretion for native-like processing and microbial hosts for speed and simplicity. For scFv and single-domains, we compare periplasmic microbial expression versus mammalian secretion to balance yield and folding. Small design-of-experiments (DoE) screens assess promoters, signal peptides, induction/feeding profiles, and cofactor conditions. The goal is a reproducible upstream prototype suitable for downstream platform development.

Purification Platform Development Service

We design orthogonal, platformable purification trains for fragments that lack Fc capture. Typical trains leverage ion exchange, HIC, mixed-mode, and affinity media tailored to fragment tags or idiotypes. We qualify host cell protein/DNA clearance, endotoxin control for microbial routes, and removal of process-related impurities such as leachables. Process descriptions include hold-time rationales and in-process controls to preserve activity and minimize aggregation.

Analytical Characterization & Method Development Service

We build a fragment-specific analytical panel that captures identity, purity, heterogeneity, and stability. Methods may include intact/subunit LC–MS, peptide mapping, CE-SDS (reducing/non-reducing), cIEF or imaged capillary focusing for charge variants, SEC with light scattering for aggregation, and binding kinetics by BLI or SPR. We also establish stability-indicating methods with forced-stress pathways (thermal, pH, oxidants, agitation) to reveal degradation vectors, informing formulation and process limits.

Stability & Pre-formulation Service

We perform pre-formulation screens to map pH windows, buffering species, excipient classes, and isotonicity strategies compatible with fragment architecture. We assess viscosity trends, opalescence, and colloidal stability across concentrations relevant to typical drug-substance handling. Accelerated and real-time stability studies use the analytical panel above to define degradation kinetics, providing data-driven recommendations for DS storage conditions and handling instructions.

Fragment Comparability & Reformat Bridging Service

When binding domains are reformatted, we design comparability matrices that align potency, kinetics, epitope preservation, and higher-order structure. This service reduces re-work during architecture optimization by quantitatively linking candidates across formats using consistent assays and acceptance criteria.