How do you substitute a raw material in an existing formulation?

What do you need before substituting a raw material in a formulation?

Before substituting a raw material in a formulation, you need the current formula with the share of each ingredient, the old raw material's technical data sheet, safety data sheet and certificates of analysis, and the product specification the formula must keep meeting. Add the reason for the change and its deadline: the last lot you can buy, the date a restriction applies, or the supply gap you are covering.

Collect what the product is approved against outside your own specification: customer specifications, approval records and any contract clause that asks for notice of a change. These set part of the re-verification scope, so find them before the bench work.

Secure the control. Keep enough of the old raw material, or retained samples of product made with it, to run a control beside every trial batch. Chemists Corner advises creating a control sample so you know how the new formula compares to the current one (Chemists Corner, 2015). Without a control, a trial result has nothing to be compared against except memory.

Open one change record for the substitution and give it an owner.

Which functions does a raw material perform in a formulation?

A raw material in a formulation performs one or more functions, such as dispersing, emulsifying, pH buffering, corrosion inhibition, thickening, wetting or solvency, and a substitution succeeds only when every one of those functions is still covered. List the functions before you look at any candidate, because the list decides what a candidate must do.

Many raw materials carry more than one function. An amine added for pH buffering can also inhibit corrosion and affect biological stability; a thickener can also stabilize an emulsion (illustrative examples). Chemists Corner notes that a single replacement might not work and that you may need several materials to replace all the functions of one ingredient (Chemists Corner, 2015).

Find the hidden functions with a knockout trial: make the full formula and the same formula without the raw material, then compare them on your standard tests (Chemists Corner, 2015). Every property that moves in the knockout batch is a function the raw material was performing, whether or not anyone wrote it down.

Write each function as a measurable property with an acceptance limit, for example pH after dilution or viscosity at a set temperature, taken from the product or customer specification or the control batch. These limits become the pass criteria for every later step.

How do you screen substitute raw material candidates?

Screen substitute raw material candidates against the function list first, then against hazard, regulatory status and compatibility, and drop each failed candidate with its reason written down. Ask current suppliers for their suggested replacements and samples (Chemists Corner, 2015), and add candidates of a different chemistry if one product cannot cover every function.

Compare hazards on the safety data sheets before any bench work. CCOHS warns that "Extreme care must be taken to make sure that one hazard is not being exchanged for another" (CCOHS, 2021). Check sections 2, 3, 8 and 9 of each candidate's sheet against the old raw material: hazard class, constituents, exposure controls, flash point and volatility.

Check regulatory status in every market. CCOHS advises determining whether a product or its ingredients appear on a regulatory list as toxic, restricted or prohibited (CCOHS, 2021). A substitute driven by a restriction should not carry a substance that is next on the same list.

Check compatibility with the process and equipment. CCOHS lists the O-rings, gaskets and hose materials that must be compatible with the substitute, the ventilation needed and the disposal route among the points to compare (CCOHS, 2021). Keep the screening table in the change record: candidate, functions covered, reason kept or dropped.

How do you plan bench trials for a substitute raw material?

Plan bench trials for a substitute raw material by fixing the pass and stop criteria from the function list before the first batch, then making every trial beside a control batch of the current formula. Criteria set after the results tend to bend toward whatever the results show.

1. Read each candidate's safety data sheet, sections 7 and 8, before handling it, and run the trials under your laboratory's written Chemical Hygiene Plan, which US employers engaged in laboratory use of hazardous chemicals must have (OSHA 29 CFR 1910.1450, 2026).

2. Change one raw material at a time and keep the rest of the formula, the order of addition and the equipment the same. Chemists Corner advises keeping as much the same as possible when comparing replacements (Chemists Corner, 2015).

3. Record every manufacturing change the candidate needs, such as order of addition, mixing time or temperature, because production instructions will need it.

4. Run the function tests first and reject batches that separate or fail. Run stability tests last, on the candidates that pass; Chemists Corner recommends functionality tests before stability tests (Chemists Corner, 2015).

5. Write the result of each batch against its limit, including failures, in the change record.

Which properties must be re-tested after a raw material substitution?

After a raw material substitution, re-test every property that maps to a function of the replaced raw material, plus stability, hazard classification and any customer approval that names the raw material or depends on the changed properties. The check table below sets that re-verification scope before the bench trials start; the example functions are illustrative and each limit comes from your own specification or control.

The row that most often reopens a finished substitution is stability: a candidate that passes every function test can still fail it, and any reformulation restarts the stability test. The hazard classification row is the one most often skipped, because an unchanged composition section on the supplier's sheet looks like proof. Fill every row before the first production batch, and record where each limit came from so a reviewer can trace each pass.

When does a raw material substitution change the SDS or a customer approval?

A raw material substitution changes the safety data sheet when it changes the hazard classification or brings significant new hazard information, and it changes a customer approval when the approval names the raw material or relies on a property the substitution moves. Check both before the first production batch ships.

In the EU, a change to a mixture classified as hazardous requires a new classification evaluation when it changes the concentration of a hazardous constituent at or above the limits in CLP Annex I Table 1.2, or substitutes or adds a constituent at or above the cut-off value (CLP Article 15(2), 2008). No new evaluation is required if valid scientific justification shows the classification will not change (CLP Article 15(3), 2008). Record that justification in the change record. If the mixture is not classified as hazardous, Article 15(2) does not apply, but the new constituent can still make it hazardous, so classify the changed mixture before it ships.

When the safety data sheet is updated for new hazard information, an EU supplier must send the revised sheet to every recipient supplied in the preceding 12 months (REACH Article 31 paragraph 9, consolidated 2026). In the US, significant new hazard information must go onto the sheet within three months and the updated sheet must ship with the first shipment after the update (OSHA 29 CFR 1910.1200(g)(5) and (g)(6), 2026).

For customer approvals, read each specification and approval record. Automotive suppliers work under the AIAG Production Part Approval Process, the industry standard for production part approval (AIAG, PPAP-4); confirm with the customer whether the change needs notification or resubmission before you ship.

Common raw material substitution mistakes

The most common raw material substitution mistake is matching the old raw material on its technical data sheet and testing only its main function, which misses a second function it was performing.

• Running trials without a control batch of the current formula made at the same time.

• Running stability first, then changing the formula after a function test fails, so stability must be repeated.

• Treating an unchanged safety data sheet section 3 as proof that classification is unaffected instead of carrying out or justifying the CLP Article 15 evaluation.

• Swapping one hazard for another, such as a less toxic but more flammable solvent, without comparing sections 2 and 9 (CCOHS, 2021).

• Leaving customer approvals until after the first production batch has shipped.

When should you call a formulation specialist about a raw material substitution?

Call a formulation specialist about a raw material substitution when no single candidate covers all the functions, when the knockout trial shows effects nobody can explain, or when the change may alter hazard classification. An unexplained knockout result means the function list is still incomplete.

Bring in a regulatory or product safety specialist when the CLP Article 15 evaluation is not clear-cut, when the product ships into several jurisdictions with different classification rules, or when the substitution is driven by a restriction. CCOHS notes that choosing a suitable alternative can be complicated and that it may be necessary to consult experienced safety professionals or occupational hygienists (CCOHS, 2021).

Bring in the supplier's technical team when it proposes a replacement but cannot state which functions it covers, and ask for data against your acceptance limits, not a general claim of equivalence.

Lubinpla works a raw material substitution from your own documents (technical data sheets, safety data sheets, certificates of analysis) and project records: it proposes substitute candidates by the functions the old raw material performed, sets the re-verification scope and plans the bench trials, marks what it could not confirm as unconfirmed, and asks for your approval at each step.