Onyx is now licensed to manufacture commercial API from our UK facility

Phase I-III API Manufacturing

Chemistry front and centre. Phase-appropriate small molecule API manufacturing.

Our phase I-III small molecule API manufacturing and development services mean we can support your molecule throughout its clinical journey. Our chemists adopt a phase-appropriate approach to ensure fit-for-purpose development at each stage.

Our team of chemists are specialists in small-scale drug substance manufacturing and work hand-in-hand with you to establish the most strategic pathway for your project. We have a strong track record of catering to the unique requirements of clinical phase projects and offer a flexible approach that is suited to today’s increasingly complex APIs.

Our laboratories support all phases of clinical trials. From quality assurance to GMP manufacture and analytical chemistry support to stability testing, we are here to optimise your drug substance supply with a focus on minimising risk and expediting timelines.

GMP Contract Manufacturing

Prior to GMP manufacture, the process outlines produced in development are converted into step-by-step instructions in a Process Record Sheet (PRS), the analytical chemistry methods and specification tables are converted into monographs describing the analytical work required to control the process.

Our team of highly trained GMP chemistry specialists follow these detailed instructions when making customer material, with our development team also being on hand to advise for those difficult stages. Any deviations are documented in line with our quality procedures through non-conformance reports (NCRs) and out of specification (OOS) reports. Corrective action and preventative action plans (CAPA) can then be put in place when required and are documented through our change control (CC) procedure.

Analytical Method Validation

Our Phase I-III small molecule API analytical support includes reference standard characterisation, forced degradation and method validation.

During early phase, the main API purity methods are validated as standard. This typically includes the HPLC achiral and chiral (if appropriate) methods and GC headspace for solvents. As part of the validation activity and to understand the stability of the API, a forced degradation study is carried out which provides evidence that the method is stability indicating. A fully characterised reference standard of the API is also produced to support HPLC assay analysis. During late phase development, further validation is carried out on the final API methods including all specified impurities and all methods used in the GMP stages of the synthesis.

API Stability

An understanding of API stability will be obtained during the development phase of a project, with this informing the ICH stability study. Onyx recommends a formal ICH study is carried out as soon as material is available from the developed synthesis. For stable compounds, an accelerated study at 40°C / 75% RH alongside a long-term study at 30°C / 65% RH or 25°C / 60% RH is typical although Onyx can support a much wider range of storage conditions as needed.


  • “Onyx Scientific provided an excellent service, responding very quickly to our needs with the flexibility that the nature of our work requires. They have coped easily with the higher volume of work and the data we are getting is as good as we could ask for. The Onyx Scientific team continues to go beyond the call of duty and will enable us to make great progress going forwards. An outstanding experience all around.”

    Dan Gooding, CEO at Nuformix Ltd