04.12.2023 by Dr. Gabriele Kaiser

IQ, OQ – Instrument Qualification in the Pharmaceutical Field and What It Means for Thermal Analysis Users

This article is dedicated in particular for users of Differential Scanning Calorimetry (DSC)  and Thermogravimetric Analysis (TGA), based on USP <1058>. 

In the pharmaceutical sector, precision and adherence to process regulations are of utmost importance. Amongst others, the United States Pharmacopeia (USP) provides a guideline, also for carrying out installation qualification (IQ) and operational qualification (OQ). They form the foundation for ensuring accuracy and reliability in pharmaceutical research and quality control.

IQ and OQ are part of the so-called analytical instrument quali­fication (AIQ) process at the user´s lab to confirm that an instrument is properly installed, works correctly and yields the expected results. A key term in this context is “demon­stration of fitness for purpose”. In the following, we would like to explain in more detail what’s behind that, mainly on the basis of USP <1058>, the corresponding chapter in the US pharmacopeia.


Risk-Based Approach

Depending on the complexity of the instrument or on how critical the measurement is, the instruments are classi­fied into three groups: A, B and C. However, depending on the purpose for which the device is used, the same instrument type can belong to one group or the other.

  • Group A includes standard equipment without mea­surement capability or user requirement for calibration. If they are obviously working well, no further qualifica­tion will be necessary.
  • Group B includes instruments providing measurement values or experimental conditions, which can affect a measurement and therefore need routine calibration, maintenance or performance checks. Such instruments may have firmware but no software, which is updated by the user.
  • Group C includes instruments with a significant degree of computerization and complexity. They are con­nected to a computer and generate electronic records. For such instruments, all elements of qualification (see below) plus software validation are required. However, software validation and instrument qualification can be combined into a single activity because the soft­ware is generally essential for running the instrument.

In USP <1058>, only a limited number of instrument examples are given: pH meters and ovens for group B as well as mass spectrometers and HPLC instruments for group C. In older USP versions, both (DSC) and (TGA) are explicitly classified as group C.

The brand-new DSC 300 Caliris® Classic
The TGA 209 F1 Nevio
The Four Qualification Phases

These are DQ (Design Qualification), IQ (Installation Quali­fication), OQ (Operational Qualification) and PQ (Perfor­mance Qualification). PQ is also sometimes called “user acceptance test (UAT)”. For complex systems, this frame­work can be extended by function specifications (FS) and/or factory acceptance tests (FAT), if necessary. Most impor­tant is that all required activities be performed in logical order. In addition, all qualification activities should be pre­defined and contemporaneously documented.

Design Qualification

DQ takes place prior to the purchase decision and defines the requirement profile of the DSC or TGA device. This includes the functional and operational specifications as well as the intended purpose of the instrument and, finally, shows that the selected instrument is appropriate. DQ can be performed by the instrument manufacturer or by the user. Some laboratories additionally issue a sepa­rate user requirement specification (URS) list, which pre­pends the DQ. In the URS, future users specify what they want the instrument to be capable of doing.


Installation Qualification

IQ stands for the documented evidence that the particu­lar DSC or TGA instrument, including software, accesso­ries, etc. is delivered as designed and as specified, that the planned environment is appropriate and that the instru­ment is properly installed. It applies to new or pre-owned DSC or TGA instruments and takes place after installation and commissioning of the instrument at the owner’s site.


Operational Qualification

OQ follows the installation qualification. It is a docu­mented collection of activities with the objective of verify­ing that the DSC or TGA instrument works properly in the selected environment and fulfills the operational specifi­cations given in the Design Qualification (DQ) and/or the user requirement specifications (URS).


Performance Qualification

PQ is the last of the four qualification phases and docu­ments continuous suitability of the DSC or TGA instru­ment for its intended use under real operating conditions. This usually also implies using typical on-site applica­tions and the laboratory’s own testing substances. The test frequency depends, amongst other aspects, on the ruggedness of the DSC or TGA device, the experience of the operator and how critical the analytical method is. Another part of performance qualification is preventive maintenance and documentation of repairs and changes in equipment. Preventive maintenance also comprises periodic calibration of the DSC or TGA instrument.



The ultimate responsibility for qualification of the DSC or TGA instrument lies with the user, whereas the term ‘user’ covers not only the operator but also that person’s super­visors, the associated instrument experts and the orga­nization’s management. Instrument manufacturers and suppliers can only advise and assist.


What NETZSCH Offers

NETZSCH Analyzing & Testing offers various services to support users during the qualification process of NETZSCH DSC or TGA units. These are:

  • IQ-OQ documents (in standard version and – option­ally – customized), including a template for recurring PQ tests
  • Installations with subsequent processing of the IQ-OQ-(PQ) documents
  • Maintenance contracts comprising calibration of the instruments on a regular basis


Interested? Please contact your local specialist: 

Watch also our video about the Development and Quality Control of Pharmaceuticals with Thermal Analysis and Rheology

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Pharma Application Book Available!

The book contains eight chapters on more than 260 pages about:

  • Thermal analysis methods (DSC, TGA, STA and Gas Analysis)
  • Characterization of amorphous and crystalline phases
  • Purity
  • Thermal stability
  • Oxidative stability
  • Storage conditions and shelf life
  • Polymorphism and Compatibility


Are you interested in the book? 

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