Chemical APIs

We are specialized in complex chemical reactions and are able to combine this with developing the most efficient processes. Supported by a robust quality system, we ensure a high product quality, manufactured in compliance with cGMP, ICH and SHE regulations. Being part of a global Aspen API network, we ensure flexibility and delivery reliability.

  • More than 100 stainless steel and glass-lined reactor vessels with capacities ranging from 250 to 10,000 liters.
  • Through our best-in-class cleaning procedures, we are able to make use of a broad range of multipurpose reaction vessels
  • Our highly active compounds are produced in units with OEB 4 and 5 classifications.
  • Microbiological fermenters convert steroidal starting material into the desired chemical intermediates
  • A broad range of purification methods are applied on large scale, such as crystallisation, filtration and chromatography
  • State-of-the art Powder Processing and Dispensing Unit for sieving, milling and micronisation

Examples of our complex chemical reactions:

  • Ethynylation
  • Oxidation (Jones, Oppenauer)
  • Grignard
  • Lithium aluminum hydride & sodium borohydride reduction
  • Liquid ammonia reduction
  • Bromination

Chemical APIs produced by Aspen Oss are the following:

* in development  ** other can include Canada, Russia, India, China, etc.


Please contact us for further information about these products or our regulatory services.


Our APIs are used in among others the following therapeutic areas:

  • Women’s health
  • Male health
  • Drug and alcohol dependency
  • Muscle relaxation
  • Oncology
  • Central nervous system
  • Anticoagulant
  • Veterinary applications