Active Ingredient

An active ingredient is the component of a formulation that produces the product's intended effect. Everything else in the formulation exists to deliver, stabilise, preserve or present the active - see excipient.

The active is usually the most expensive component per kilogram and the most tightly specified, since its concentration determines whether the product works. Specifications for actives are typically narrower than for other ingredients, and confirming concentration is normally part of batch release testing - it will appear on the certificate of analysis.

Actives also drive the regulatory position. In several sectors the active substance is regulated separately from the finished product, and both may require approval before sale - biocidal products and plant protection products being the clearest examples. The active is also usually what determines the product's hazard classification, and therefore its labelling and safety data sheet.

Because the active carries both the cost and the regulatory burden, it is where reformulation pressure concentrates. If an active becomes restricted or unavailable, the product generally cannot continue unchanged - see product reformulation and agrochemicals for a sector where this happens regularly.

Confirm that active concentration is on the release specification and appears on the certificate of analysis. It is the parameter that determines whether the product works, and it is occasionally omitted where a manufacturer has assumed testing was covered elsewhere. Where an active is the dominant cost, it is also worth asking whether the manufacturer buys it or you supply it, since that single decision can move a large share of the product cost between the two arrangements.

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