Oxygen monographs are used to provide healthcare facilities with a framework for the production of oxygen. With the Covid-19 pandemic exposing weaknesses in not only the medical oxygen supply chain, but also existing technology, new monographs can help advance future designs in onsite oxygen generation.

Providing expert insight and analysis on the current state of oxygen monographs in Europe, Dr. Herbert Schmidt, Pharmacist and part of the Norms and Standards for Pharmaeuticals Team at the World Health Organisation (WHO), spoke with gasworld during the Medical Gases Virtual Event 2022.

Guidance on oxygen 

Referring to oxygen as a lifesaving essential medicine, Schmidt said that there is no substitution. 

WHO’s web page provides comprehensive information on oxygen as a medicine and details the need to provide equal access to quality assured medicinal oxygen to enable healthcare professionals and caretakers to safely administer the gas. 

Promoting access to oxygen and mitigating oxygen inequity has been a project by the organisation.

“In the course of the Covid-19 pandemic devastating oxygen shortages became evident. These shortages led to countless preventable deaths in low and middle income countries (LMICs),” he said. 

Access to Covid-19 Tools (ACT) Accelerator 

ACT is a development by WHO to enhance global collaboration to accelerate the development, production and equitable access to Covid-19 tests, therapeutics, and vaccines. 

The organisation is also publishing technical specifications and oxygen clinical guidelines to promote its safe use. 

“The draft revision of the monograph on oxygen is the topic of my presentation today,” added Schmidt. 

Revised monographs 

A revision of the monograph on oxygen in the International Pharmacopoeia was initiated to promote universal and equivale access to medicinal oxygen. 

Schmidt outlined the key reasons for a revision, providing the following points: 

  •  Clarifying that WHO member states can safely apply to Covid-19 or other patients oxygen generated.
  •  Putting an end to discussions as to whether industrial oxygen can be used for human application 
  •  Harmonising quality requirement for oxygen with requirements of other pharmacopoeias

Scope – structure of monograph

“We initiated the revision to clarify that both oxygen qualities, oxygen produced by distillation and oxygen produced by adsorption can safely be applied to patients,” explained Schmidt.

“Therefore, we decided to not describe the two qualities in separate monographs as other pharmacopeia’s but to describe both qualities and one monograph on medicinal oxygen.”

The main part of the monograph defines medicinal oxygen as oxygen 93% or oxygen 99.5%.

It provides information on molecular formula, the relative molecular mass and category and also defines medicinal oxygen by purity type.

“It is applied in combination with ambient or compressed air of a suitable quality or in pure form, depending on the clinical medical necessity,” added Schmidt.

Oxygen 99.5%

This must contain no less than 99.5% oxygen. Produced from ambient air through cryogenic distillation, the production method is validated to demonstrate that oxygen 99.5% complies with a set of limits including carbon dioxide, carbon monoxide, and water content.

Oxygen 93% 

Containing no less than 90% and no more than 96% oxygen, the remainder of the gas consists of argon and nitrogen and is produced from ambient air by single state pressure-swing adsorption (PSA) or vacuum-swing adsorption (VSA).

“It is produced from ambient air by single state PSA or VSA.”

If the gas is released, an assay test must be used to test its identity. Detector tubes will determine the purity and a paramagnetic analyser should determine the content of the gas. 

The International Pharmacopeia has also aligned its parameters to match as closely as possible to other international pharmacopeias. 

Norms and standards 

WHO norms and standards are developed through an ‘open and transparent’ process and are made in consultation with an international panel of experts, WHO Collaborating Centres and laboratories. 

“Our process applies conflict of interest and confidentiality rules,” added Schmidt. 

The revision will be submitted for possible adoption to the Expert Committee on Specifications for Pharmaceutical Preparations (ECSPP). 

The monograph defines the pharmaceutical quality of oxygen products that can be safely applied to patients. 

It does not provide guidance on the frequency of testing, qualify of feed air, impurities origination from hospital piping system and the clinical use of medicinal oxygen.

If adopted the monograph will be included in the next edition of the International Pharmacopoeia.