Case study — A stable triple-API topical, from development to a successful First-in-Human study

August 7, 2026

How Zelmic and CTC took a US biotech’s complex topical candidate from formulation all the way to a completed Phase I trial — within one integrated pathway.

The challenge

A US-based biotech approached the CTR Group with an ambitious topical candidate: a single formulation combining three active pharmaceutical ingredients (APIs).

Combining three actives in one topical base is far from trivial. The APIs have to be chemically compatible, physically stable across shelf life, and analytically separable so each can be measured accurately and its degradation tracked. On top of that, the client needed a robust, GMP-manufactured product ready to dose in a First-in-Human (FIH) study — on a timeline that left no room for reformulation surprises.

What Zelmic did

Zelmic’s formulation team began with pre-formulation work and excipient screening to identify a base in which all three APIs stayed compatible and stable. In parallel, the analytical group developed stability-indicating methods capable of quantifying each API individually and detecting degradation products, then ran stability studies to confirm the formulation held up over time.

Once the formulation and methods were locked, Zelmic manufactured the investigational medicinal product (IMP) under EU GMP at its facility in Lund, Sweden, with Qualified Person (QP) release of the clinical batch.

A seamless handover to CTC

Because Zelmic and CTC Clinical Trial Consultants are part of the same group (CTR), the transition from GMP supply to clinical conduct happened without the usual handover friction. The QP-released IMP was delivered to CTC, which ran the First-in-Human study.

Shared documentation practices and continuity between the development, manufacturing and clinical teams meant fewer interfaces, less knowledge lost in translation, and a faster path to first dose.

The outcome

The triple-API topical proved stable, the IMP was delivered on schedule, and the First-in-Human study was completed successfully — delivering the early safety and pharmacokinetic data the client needed to advance their program, on a validated formulation they can build on.

The takeaway

Complex topical products don’t have to mean complex programs. Bringing formulation science, analytical chemistry, GMP manufacturing and clinical conduct under one integrated pathway turns a high-risk, multi-API challenge into a single, coordinated effort — from concept to first-in-human.

Working on a complex topical or early-phase program? Talk to our team about formulation, GMP supply and the integrated path to the clinic. → https://zelmic.se/contact/

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