Quality – only the best for our customers


Our concept of quality and the implementation thereof in our finished products form the pillars of our success.

  • QC – quality control: Comprehensive quality control using cutting-edge inspection machines.
  • IMS – integrated quality management system: All branches are subject to a comprehensive standardised quality management system.
  • CI – continuous improvement: Our policy of “flawless products” is supported by our conscientious employees and numerous, ongoing improvement measures.

Quality in processes and products

  • Quality inspections in accordance with the European, Japanese and US-pharmacopeia
  • Regular checks of heavy metal content
  • Microbiological and particle testings
  • Comprehensive quality controls with state-of-the-art inspection machines
  • Top-class, cutting-edge production and quality testing facilities

Stoelzle aspires toward the constant improvement of its process capability. Our employees, as well as digitalisation and improvement measures, shall support us in this endeavour and we continuously invest in first-class inspection machines and state-of-the-art production systems.


Quality standards

  • ISO 9001
  • ISO 15378 (GMP)
  • Active Drugmaster File at FDA and Canada

Quality in the laboratory

Microbiological laboratory

The tests performed in the microbiological laboratory are focused on three fields:

  • Microbiological- and particle purity of the produced containers
  • Environmental monitoring of microbiological and particle count of the air
  • Monitoring of the hygienic behavior of the employees


Chemical laboratory

In our well-equipped chemical laboratory we have a years-long experience in a variety of tests for quality assurance and production support. These tests include:

  • Determination of hydrolytic resistance (inner surface and glass grains) according to the latest versions of E.P./USP, ISO 4802-1 and ISO 719
  • Measurements of glass color parameters and density
  • Monitoring of selected raw material parameters (e.g. content of iron, alumina, sulfate)


Regular participation in comparative/ring trials (within the Stoelzle Glass Group and with external laboratories) ensures a constant high quality and accuracy of the testing procedures.

Customer satisfaction

This is our ultimate goal – profit from a global network of client advisers, specifically tailored production and small batch sizes. Profit from our customer-specific logistics solutions and the rapid product availability.


Technical customer service

We support our customers before, during and after bottling. With proactive customer visits, we enable a smooth and hassle-free conversion to new items. We are also happy to provide you with technical support for on-site test bottling.

Continuous improvement

We as the Stoelzle team are highly qualified and are always striving for improvement and increased efficiency. We do not settle for average performance. In order to constantly keep improving, we implement a multitude of internal systems:

  • Stoelzle ideas management: Our internal improvement process for Stoelzle employees.
  • CAPA: We implemented this structured method for solving problems and identifying causes.
  • Plan do check act (PDCA): A structured approach for dealing with problems, difficulties, changes, risks and opportunities.
  • Training & qualification of the employees: Group-wide, cross-factory advanced training promotes the competence and qualification of the employees.
  • Zero-error strategy: Our corporate culture, the employee attitude, and our standards all support error-free processes and products.