Follow recovery from load to pool.

Downstream development turns a harvest into a purified, formulated bulk through a train of capture, polishing, filtration, concentration and buffer exchange steps. Each step is a trade between yield and quality, and each depends on the columns, membranes, buffers and methods used. The evidence for those trades usually sits in instrument exports, fraction spreadsheets, assay reports and notebook entries.

A page-based ELN is built to record what was done. It can hold a pasted fraction table and a note of the chosen window, but the fractions, their assays, the method version and the column’s history are not records it can follow. When the process moves to pilot scale or another site, someone rebuilds the argument from exports, and the reason a pool was chosen is the part most often lost. Development guidance expects that reason to survive: each significant change in a biological drug substance’s manufacturing history should be explained and assessed for its potential to affect quality.¹

Seal is where the protocol runs, or it reads the run from the systems that produced it. Fractions, pools, samples and results are records with their own history, connected to the method version, column and buffers behind them. A pooling decision becomes an argument a reviewer can follow, and the purification train carries that argument into scale-up and transfer.

A protocol in Seal carries instructions, fields, calculations, linked samples and review steps. During execution the team records actual values, observations, variations and instrument references, while ÄKTA and other instruments keep their acquisition data.

A purification run records the input pool, method version, equipment, solutions and consumables, then the fractions, samples and conclusion. The fictional RUN-AEX-MAB14-047 keeps a bounded pressure alarm and an excluded shoulder fraction on the record, with the reason for exclusion, rather than leaving them out of the summary.

Neil can help prepare the configuration and analyse the results. The team tests the workflow and defines the review and approval requirements before its intended use. A later revision of the protocol does not rewrite the runs made under an earlier one.

The fictional CHR-014 example compares two pooling windows on one chromatography step. F03–F06 recovers 1,400 mg in 80 mL, or 70% of the 2,000 mg loaded. F02–F07 recovers 1,640 mg in 120 mL, or 82%.

The extra 240 mg comes from two fractions with host-cell protein results of 70 and 95 ng/mg, against 9 to 22 ng/mg in the core fractions. Host-cell proteins are process-related impurities that come from the cell substrate,² so the wider pool buys recovery with an impurity burden that neither window has yet measured. No acceptance criterion has been supplied. A step’s protein recovery does not establish pooled quality, impurity clearance, overall process yield or scale equivalence.

The calculation is kept with the result. Recovery sums the protein mass and volume of the selected fractions and divides the selected mass by the 2,000 mg loaded to this step. Protein mass uses PROT-02 v04 and HCP uses HCP-05 v02, on method DSP-M07 v03, column COL-008, cycle 12. The eight fractions of 20 mL account for 1,700 mg; flow-through, washes, residual material and other losses are not supplied, so this is not a complete mass balance.

The trace above the bars is synthetic and shows the collection intervals only. Recovery comes from the fraction assays, not from UV peak area. In a configured workflow the actual chromatogram, method version and instrument events are linked to the fraction records, and a proposed change to a collection rule remains a draft until the team reviews and tests it.

Retain the resin lot, column geometry, packing and cycle history, buffers, actual flow and pressure, collection events and sample methods with each run. A later comparison is then between like and like, and a pooling decision stays connected to the run that produced it.

Bring ÄKTA / UNICORN exports, fraction assays and filtration studies together, then ask Neil for a run comparison, pooling assessment, mass-balance reconciliation, proposed study or transfer work plan. Its output retains source versions, calculations, missing evidence and open decisions, so a reviewer starts from what was measured rather than from a summary of it.

For CHR-014 the useful proposal is a study, not an answer. The downstream scientist prepares representative candidate pools at the intended fraction proportions and records aliquots, actual volumes and sample handling. The analytical scientist measures pooled protein and HCP, plus the quality attributes the study requires, and verifies method suitability and any dilution or matrix effects. The process lead compares the measured pool profiles, recovery and suitability for the next step against requirements agreed in advance, and records which option proceeds and why.

The draft does not select or approve a pool, establish impurity clearance or prove scale equivalence. Everything in the middle column is preparation; the pooling decision and the next study need scientific review.

In line with the EU’s draft GMP Annex 22 on AI, Neil is not used in GMP execution. It helps set up configuration, which your team verifies and releases under change control. Customer data is not used to train AI models, and the requester’s permissions govern what Neil can read. See how Neil fits Annex 22 and more about Neil.

Chromatography methods retain the column and resin, phases, load, flow, pressure, transitions, collection rules, cleaning and criteria as versioned, executable definitions. The fictional METHOD-AEX-MAB14-v09 sets conductivity-triggered collection boundaries; a fraction records the collection window, signal context, inclusion decision and rationale.

Filtration, concentration and buffer exchange follow the same material. Connect membrane identity and area, feed and retentate quantities, permeate, process conditions, sample withdrawals and hold-up estimates. Compare recovery on the same calculation basis, keep measured losses separate from assumptions, and do not equate a single step’s recovery with overall process yield.

An intermediate pool carries its parent fractions, actual quantities, containers, transfers, storage and hold intervals, with its sampling losses and measured composition. You can see what entered each pool, where it went and which results support its next use; its quality and suitability for the next step still need their own assessment.

Columns, resins, membranes and filters keep their own lifecycle: identity, lot, packing or conditioning, performance, cycles, product contact, integrity, cleaning, storage, reuse and retirement. That history matters beyond one run. The lifetime use of a chromatography resin should be stated, with clearance studies to support its reuse,³ and column lifetime studied in small-scale models should be confirmed in commercial-scale production.¹

Buffers and process solutions record their formula, source lots, preparation, tests, hold and consumption, and buffer preparation can run in Seal as well. When a lot or a column changes, the dependent runs remain traceable.

Retain corrections and uncertainty with the calculation, and record the boundary of any clearance claim. The CHR-014 fractions account for 1,700 of the 2,000 mg loaded; until flow-through, washes and residual material are supplied, the other 300 mg is unexplained rather than lost. The fictional BAL-AEX-047-v02 is a reconciled balance that still shows an estimated line-hold-up loss.

Samples link each result to its pool or fraction, process position, time, handling and method. Instrument source files, suitability, repeats and invalidations stay connected to the interpretation. Missing quality data remain missing rather than becoming an approved pool.

Clearance is a claim about a step under stated conditions. The process’s ability to remove product-related and process-related impurities should be shown by study,¹ and clearance studies, including spiking experiments at laboratory scale, can show the removal of host-cell proteins.² Where a separation step removes virus, investigating how the virus distributes across its fractions is recommended where possible.³ Keep the study, its conditions and its boundary with the claim, so a later change to the step can be assessed against it.

The fictional SCALE-AEX-MAB14-v05 is an approved pilot-to-commercial model that records a pressure restriction on the receiving skid. A matching setting does not prove scale equivalence: bed height, residence time and load can match while the receiving equipment’s pressure limit, hold-up or mixing do not.

Development guidance sets the same expectation. A design space developed at small or pilot scale needs its relevance to production scale justified, with the risks of scale-up discussed.⁴ Commercial-scale batches should confirm the results of the small-scale studies used to support process validation.¹ For a chromatography step in a viral clearance study, the scale-down model should match commercial manufacture in bed height, linear flow rate, contact time, buffer and resin type, pH, temperature, conductivity and product concentration.³

Ask Neil to compare the receiving equipment, loading, residence time, flow, pressure and hold assumptions with the model, and to list the evidence needed to resolve each difference. The model’s assumptions, predictions and uncertainty are versioned, so a change to the model is reviewed like a change to the method.

Buffers, equipment assumptions, expected profiles and known sensitivities travel with the train as well. Ask Neil to compare the receiving site’s local differences and prepare the evidence requests.

Technology transfer moves product and process knowledge between development and manufacturing, and that knowledge forms the basis for the manufacturing process, control strategy, process validation approach and continual improvement.⁵ A transfer report written at the end of development summarises that knowledge. A transfer built from the development records carries the knowledge itself, with the runs behind each range.

In the fictional TT-DS-MAB14-SITE02, the virus-filter configuration requires direct confirmation at the receiving site rather than inheriting the development result. The tech transfer blueprint covers the receiving side.

Connect permitted instrument files, fraction maps, analytical results and material records, or supply the relevant exports. Source APIs, configuration and permissions determine the available connection. For ÄKTA, Seal can collect completed UNICORN exports of curves and peak tables and relate the runs, fractions and later analytical results; acquisition and evaluation stay in UNICORN, and the complete result archive is kept separately for reopening there. A pool records which fractions contributed, so a purity result can be traced back through the pool to the original run. See all integrations.

Compare the options, inspect the calculations and agree the next experiment together. Then extend the same records across capture, polishing, filtration and transfer, and upstream into cell culture development.